Browse Topic: Mirrors

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Unsteady Boundary Layer Transition Measurements on a Rotor in Forward FlightF-0074-2018-126925/7/2024
ABSTRACT A proof of concept test to measure the unsteady boundary layer transition locations on the lower surface of a Machscaled rotor in forward flight was performed during the Summer of 2017 in the NASA Langley 14- by 22-Foot Subsonic Tunnel. The transition locations were measured using high-speed infrared thermography with a rotating mirror assembly that could be remotely actuated to acquire data at several rotor azimuths. Data were acquired for eight unique rotor flight conditions for a range of advance ratios (μ=0:10 : 0:38), thrust coefficients (CT/α =0:04 : 0:12) and rotor shaft angles (αs = -6 deg : 0 deg). This paper presents the transition locations as a function of azimuth and radius for an advance ratio of, μ, of 0.30, and thrust coefficent, CT/α, of 0.08. At this condition, the lower surface is fully laminar on the retreating side and mostly turbulent on the advancing side except near the tip. The tip airfoils were greater than 60 percent laminar on the lower surface advancing side. Capturing the location of natural transition on a rotating blade in forward flight represents a new advancement toward understanding the boundary layer state and its important contribution to rotor aerodynamics. Documentation of the boundary layer transition location during testing is critical to understanding scaling model to full-scale performance data, validation of newly developed turbulence models, and the design of the next generation of high performance rotor blades.
Overmeyer, Austin, Heineck, J.T., Wolf, Christian
Measuring the Radius of Curvature of Convex MirrorsJ1246_202110 (Current)10/15/2021
The SAE Recommended Practice is intended for use in measuring the radius of curvature (ROC) of spherical convex mirrors.
Driver Vision Standards Committee
Motor Vehicle Glazing - Electrical CircuitsJ216_202109 (Current)9/1/2021
This SAE Recommended Practice establishes limits for electrical circuits on motor vehicle safety glazing materials.
Glazing Materials Standards Committee
LIGHT, DESK, AIRCRAFTAS7768/1B (Current)11/9/2020
A-20C Interior Lighting
Noise, Vibration, and Harshness Considerations for Autonomous Vehicle Perception Equipment2020-01-04824/14/2020
Automakers looking to remake their traditional vehicle line-up into autonomous vehicles, Noise, Vibration, and Harshness (NVH) considerations for autonomous vehicles are soon to follow. While traditional NVH considerations still must be applied to carry-over systems, additional components are required for an autonomous vehicle to operate. These additional components needed for autonomy also require NVH analysis and optimization. Autonomous vehicles rely on a suite of sensors, including Light Detection and Ranging (LiDAR) and cameras placed at optimal points on the vehicle for maximum coverage and utilization. In this study, the NVH considerations of autonomous vehicles are examined, focusing on the additional perception equipment installed in autonomous vehicles. In particular, the nature of modifications to existing vehicles to increase the level of autonomy, and the associated NVH characteristics of these alterations, are reviewed with suggestions for future application to autonomous vehicles. A case study in the design of an original autonomous vehicle based on a production all-electric car, a 2017 Chevrolet Bolt, is outlined. A detailed description of the NVH design and verification process for this vehicle is provided, with results giving insight into the NVH design of autonomous vehicles and the challenges that are created.
Gates, Charlie, Bastiaan, Jennifer, Jadhav, Prashant, Baqersad, Javad, Peters, Diane
N&V Component Structural Integration and Mounted Component Durability Implications2020-01-13964/14/2020
Exterior component integration presents competing performance challenges for balanced exterior styling, safety, ‘structural feel’ [1] and durability. Industry standard practices utilize noise and vibration mode maps and source-path-receiver [2] considerations for component mode frequency placement. This modal frequency placement has an influence on ‘structural feel’ and durability performance. Challenges have increased with additional styling content, geometric overhang from attachment points, component size and mass, and sensor modules. Base excitation at component attachment interfaces are increase due to relative positioning of the suspension and propulsion vehicle source inputs. These components might include headlamps, side mirrors, end gates, bumpers and fascia assemblies. Here, we establish basic expectations for the behavior of these systems, and ultimately consolidate existing rationales that are applied to these systems. We consider a simple two degree-of-freedom system subject to a base excitation consisting of masses attached via springs and dampers. Component mode decoupling, vibration amplification and basic design guidance relationships are suggested.
Stebbins, Mark, Schudt, Joseph
Virtual Verification of Light Reflection for Cluster and Side Mirror in Real Time Scenario2020-01-05684/14/2020
In the very automobile world trends are changing at a very fast pace, due to continuous expectation changes by user and new regulatory requirements demand from government authorities with a very stringent timeline. In the current scenario, manufacturer has to wait for mock up for concept selection and physical proto build to conclude open points of design verification. This complete process takes more than a year to enhance the design maturity for further builds. In VECV we have created Cluster design standard to meet different level of cluster illumination & reflection at virtual level. We are defining the cluster light illumination based on our rigorous study on cluster reflection impact on side glass, windscreen and mirror. Accordingly we have packaged our mirror to minimize the impact of cluster reflection on mirror visibility. With the help of virtual verification of cluster and Side mirror inter co-relation of packaging, we significantly reduced the time loss and save huge cost required for developing proto build. Different options of mirror and cluster can be verified in quick session. With the help of virtual verification of mirror and cluster we are able to meet different regulatory compliances for light illumination without building a single proto build.
Bhatnagar, Manas, Biswal, Jyotiranjan, Sharma, Saurabh
Decision Making and Trajectory Planning of Intelligent Vehicle’ s Lane-Changing Behavior on Highways under Multi-Objective Constrains2020-01-01244/14/2020
Discretionary lane changing is commonly seen in highway driving. Intelligent vehicles are expected to change lanes discretionarily for better driving experience and higher traffic efficiency. This study proposed to optimize the decision-making and trajectory-planning process so that intelligent vehicles made lane changes not only with driving safety taken into account, but also with the goal to improve driving comfort as well as to meet the driver’ s expectation. The mechanism of how various factors contribute to the driver’s intention to change lanes was studied by carrying out a series of driving simulation experiments, and a Lane-Changing Intention Generation (LCIG) model based on Bi-directional Long Short-Term Memory (Bi-LSTM) was proposed. The inputs of the Bi-LSTM were data fragments of several influencing factors including the relative velocity and the distance between the relative vehicles, the type of the preceding vehicles, and the average velocity of the adjacent traffic flows, that over a certain period of time, which was determined via examining subjects’ visual behaviors of the left view mirror or the right view mirror. By combining the LCIG model with a feasibility judgement model which was based on minimum safety spacing (MSS), a lane-changing decision-making model satisfying driving safety and drivers’ expectation was proposed. The model was trained with a part of trajectory dataset obtained from the simulation driving experiments. The jerk was taken into full consideration as boundary condition on the basis of seventh-degree polynomial trajectory planning. The proposed decision-making model were verified against a test dataset from the other parts of experimental data and the results show that the model resembles the lane-changing decision-making process of human drivers in real-world.
Nie, Linzhen, Yin, Zhishuai, Huang, Haoran
Sensor Heat Relief20AVEP03_073/1/2020
Canatu's carbon nanobots keep critical sensor surfaces -and LED headlamps - clean in sub-freezing weather. Sensor surfaces that are exposed to weather need to be kept clean so that ADAS and autonomous driving systems can function safely. Ice build-up in cold conditions is of particular concern, but Canatu thinks it has a solution. The Finland-based technology company has developed a transparent, highly conductive heater element that does not require metallic wires to be placed in front of the sensor. These elements keep lidar sensors and cameras ice-free, thanks to carbon nanobot (CNB) heaters.
Berman, Bradley
Products of Tomorrow: February 2020TBMG-359682/1/2020
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Basic technical requirements for ballistic safety to guarantee the quality of civilian automotive armoring services in Brazil2019-36-03291/13/2020
Brazil is the largest civilian armored vehicle market in the world with more than 16,000 new protected units produced in 2018, followed by Mexico with 7,000 automobiles, according to Brazilian Army (BA) data. In this context, this paper presents an overview of Brazilian market for civilian vehicle armoring, definitions and characteristics of transparent and opaque ballistic resistance protective materials according to U. S. Department of Justice, the National Institute of Justice, NIJ Standard 0108.01. Based on this premises, the paper addresses basic technical requirements for ballistic safety in design and process to guarantee minimum quality of armoring services. The purpose of this paper is to safeguard the original features and functionality of the automotive components while simultaneously providing recommended ballistic protection of the vehicle with quality. The adoption of minimum automotive quality management system requirements from IATF 16949 International Automotive Task Force, in armoring services with different types of vehicle models and brands, will encourage to reduce tack time production, to improve vehicle armored quality, to reduce final reworks, to keep original equipment guarantees, to allow the incoming material traceability and to provide reassembly quality improvements.
Candido, Guido Muzio, Kaminski, Paulo Carlos
A mirrorless future? NHTSA seeks input on camera vision systems19AUTP11_1311/1/2019
The U.S. National Highway Traffic Safety Administration (NHTSA) in early October distributed a notice soliciting industry and public input on whether to allow “camera monitoring systems” to replace rear- and sideview exterior mirrors mandated since 1968 in U.S. auto safety standards. The agency said in a notice in the online Federal Register that it is seeking outside research and data about the potential safety impacts of replacing conventional fixed mirrors with camera-based vision systems. The action is one step in the process to inform a potential proposal to alter the mirror requirement for future production vehicles sold in the U.S. Mirrorless vehicles have long been advocated by automotive stylists and engineers seeking sleeker looks and improved safety. They also can help improve a vehicle's fuel efficiency because the camera setups - multiple exterior cameras feeding a flat-screen array inside the cabin - have lower aerodynamic resistance than traditional stalk-mounted fixed mirrors.
Brooke, Lindsay
Recovering Color Images from Scattered LightTBMG-3547811/1/2019
Engineers at Duke University have developed a method for extracting a color image from a single exposure of light scattered through a mostly opaque material. The technique has applications in a wide range of fields from healthcare to astronomy.
Researchers Turn off Backscattering, Aim to Improve Optical Data TransmissionTBMG-3547211/1/2019
Engineers at the University of Illinois have found a way to redirect misfit light waves to reduce energy loss during optical data transmission. In a study, researchers exploited an interaction between light and sound waves to suppress the scattering of light from material defects — which could lead to improved fiber optic communication.
Windshield Defrosting Analysis: A Numerical and Experimental Approach2019-28-011510/11/2019
The outside visibility through the windshield and ORVM visibility through the side glasses are critical for safe driving. The frost deposition on the Windshield and side glasses in the cold climatic condition impairs the outside and ORVM visibility during driving and hence leads to an unsafe driving condition. In India, the regulation AIS-084 governs the defrosting standard. The defrosting performance evaluation by testing cannot be performed at concept stage when the vehicle prototype is not available. It also increases the cost of vehicle development due to increase in the number of prototype used for testing. This paper explains about the in-house developed CFD methodology to evaluate the windshield defrosting performance of the vehicle in the concept stage when no vehicle proto is available and cost of countermeasure for defrosting performance improvent is very less. This methodology is implemented for some of the existing models. The results of CFD simulations are compared to the experimental data using a correlation study and the correlation coefficient of numerical and experimental measurements were reported. CFD simulation was in good agreement with the experimental study and the so development CFD methodology is further used for design parameter studies.
Kumar, Chandan, Makana, Mohan, Regin, Felix, Garg, Amit, Pedamallu, Durga Prasad
Design Optimization of Trunk Lid Torsion Bar Type Trunk Lid Pop Up Mechanism2019-28-011110/11/2019
Trunk lid (TL) can be opened using hydraulic or pneumatic balancers, coil springs, torsion bars or combination of the above. TL Opening Mechanism specific to Trunk Lid Torsion Bar (TLTB) is being discussed in the paper. After de-latching, TL should open smoothly and stop at such a height that it is visible from driver seat. The system consists of a four bar linkage mechanism, in which the fixed link is formed by BIW Bracket. Connecting link, TL Hinge Arm and Torsion bar arm form the other three links. Hinge has its one end attached to TL and the other end to BIW bracket. Torsion bar arm transfers torque to TL hinge through the connecting link. Major challenges in designing TLTB mechanism are part tolerances, C.G position and Weight variations in individual parts, Torsion bar Raw Material variation, uncertain friction in the system etc. If above challenges are not addressed properly, then issues like TL not popping up to desired level consistently and smoothly and hard closing may occur. TL pops up when torque due to torsion bar is greater than the combination of torque due to TL weight and friction at linkages. Considering the above challenges and drop in elasticity of TLTB with time, upper and lower values of torques are derived. When lower value torque of torsion bar is greater than the upper value torque of TL weight torque and friction torque, TL always opens. If effects of the tolerances are not considered then pop up of TL is uncertain. The difference between these torques should be optimal so as to ensure smooth pop up. This paper outlines the design optimization of Trunk Lid Pop up Mechanism while addressing afore mentioned challenges.
Kasarla, Sharath Chandra, Singh, Amit
Development and Influence of Setting Process Variables in Single Point Incremental Sheet Metal Forming of AA 8011 Using Complex Proportional Assessment and ANOVA2019-28-006410/11/2019
Single point Incremental forming (SPIF) is a metal forming process that has achieved impeccable quality since the early 1990s. ISF is a very limited twisting process in which an improved device that must be used after a particular direction travels on a metal sheet to form the desired shape. Process parameters such as axial feed (mm), feed (mm / min), tool diameter (mm) and depth (mm) at the interface between samples during SPIF greatly affect the quality of the cone. Maximum thinning (mm), cone height (mm), wall angle (mm), formation time (minutes), etc. The purpose of this study was to study these parameters by improving the cone mass formed by VMC. For a detailed study of these parameters, experiments were performed using the orthogonal array L9. Output parameters such as mechanical quality effects were analysed using COPRAS (Complex Proportional Assessment of alternatives) and ANOVA.
Sivam Sundarlingam Paramasivam, Sundar Singh, Kumaran, Durai, Loganathan, Ganesh Babu, Saravanan, Krishnaswamy, Rajendran, Raj, Sriram, Harish
Laser-Pointing System Transmits Data from Tiny SatellitesTBMG-351549/1/2019
Since 1998, almost 2,000 shoebox-sized satellites known as CubeSats have been launched into space. Due to their small frame and the fact that they can be made from off-the-shelf parts, CubeSats are significantly more affordable to build and launch than traditional satellites that cost hundreds of millions of dollars.
Personnel Protection - Skid Steer LoadersJ1388_201907 (Current)7/3/2019
This SAE Standard is intended to provide personnel protection guidelines for skid steer loaders. This document is intended as a guide towards standard practice, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. This document provides performance criteria for newly manufactured loaders and it is not intended for in-service machines.
OPTC1, Personnel Protection (General)
Design of an Energy-Efficient Critical Angle Lens ReflectorTBMG-347687/1/2019
The critical angle lens reflector has commercial applications that supersede ordinary mirrored reflectors. The physics of the critical angle lens reflector are based on the optics principle of total internal reflection. Total internal reflection is characterized as follows: (1) as shown in Figure 2, the light rays are reflected off of the reflecting surface whereby the angle of reflection – with respect to the perpendicular to the reflecting surface – is equal to the angle of incidence of the ray, and (2) the reflection of the light ray takes place with no loss of energy upon reflection.
Revolutionary Camera Allows Scientists to Predict Evolution of Ancient StarsTBMG-347757/1/2019
Scientists at the University of Sheffield have been working with HiPERCAM, a high-speed, multicolor camera, which is capable of taking more than 1,000 images per second, allowing experts to measure both the mass and the radius of a cool subdwarf star for the first time.
Rearview cameras COME INTO SIGHT19TOFHP06_066/1/2019
Momentum is building behind replacing mirrors with camera monitor systems as the technology edges closer to regulatory approval. To borrow from a well-known automotive phrase, “Objects in mirror” aren't really closer than they appear-because the mirror itself appears poised to become another relic of the analog age. Long-debated since the technology quickly became more sophisticated and less costly, camera systems to replace external rearview mirrors for trucks and other on- and off-road commercial vehicles are likely just around the corner. With surprisingly little fanfare last December, the Federal Motor Carrier Safety Admin. (FMCSA) granted a 5-year exemption for on-road commercial vehicles to install Stoneridge Inc.'s MirrorEye Camera Monitor System (CMS) in place of conventional mirrors. It's been off to the races since, as Stoneridge and other rearview-camera developers sense that unconditional change to FMCSA's current commercial-vehicle mirror regulation is next.
Visnic, Bill
WHAT WE'RE DRIVING19AUTP05_105/1/2019
America needs more midsized pickups. The case for the new Ford Ranger is made by increasingly strong sales of GM's models and the perennial fan base of the Toyota Tacoma and Nissan Frontier. And now Jeep's back in the game. A growing number of U.S. pickup fans want something more parkable and fuel-efficient than the fullsizers. I used to rant about this to Derek Kuzak, Ford's former head of product development, whenever our paths crossed. “Don't kill Ranger, not everybody wants an F-150,” I'd plead. He'd patiently agree, while noting that “small” pickups cost OEMs nearly as much to produce as the big ones, with lower margins.
Coating Prevents Fogging on Transparent SurfacesTBMG-344095/1/2019
Anyone who skis, wears glasses, uses a camera, or drives a car is familiar with the problem: Coming into a humid environment from the cold causes eyewear, camera lenses, or windshields to quickly fog up. Researchers have developed a new transparent material coating that greatly reduces this effect. A few nanometers thick, the durable coating is made of gold nanoparticles embedded in non-conductive titanium oxide.
Breakthrough Lab-on-a-Chip Detects Cancer Faster, Cheaper, Less InvasivelyTBMG-344335/1/2019
A new ultrasensitive diagnostic device invented by researchers at the University of Kansas, The University of Kansas Cancer Center, and KU Medical Center could allow doctors to detect cancer quickly from a droplet of blood or plasma, leading to timelier interventions and better outcomes for patients.
Study of Replacing the Traditional Electromechanical Relay with the Full Semiconductor Solution of Bussed Electrical Center2019-01-04844/2/2019
To face the challenges of CO2 emission and automated driving, the electrical distribution system (EDS), as the basis of all electronic loads, needs to be continuously changed. Traditional bussed electrical center (BEC) has limited functions such as simple switch and fuse protection, while the full semiconductor solution of smart BEC can provide more accurate diagnosis, faster response, higher reliability with lower power loss and smaller space. This paper will introduce the practical function of the smart BEC: in normal operation of the car, the voltage and current of the loads can be detected by the smart BEC. Once in abnormal, immediate feedback will be transferred from smart BEC to the whole system and a related response will be triggered in time, while the cost of power harness can also be optimized. In parking mode, the quiescent current of the loads from KL30 can be detected by smart BEC, which could prevent against leakage. Automated driving is a hot topic, many people focus on functional safety and redundancy of the actuators in the car, which can only be realized by the safe power supply. Therefore, this paper will also describe the fail safe and fail operational of power supply with smart BEC. Of course, replacing traditional relays with semiconductors will face many challenges, such as the switch off energy for inductive load, inrush current for capacitive load, thermal problem of the system, cost optimization and so on. The paper will introduce the solutions to these challenges. These solutions have practical significance because they are based on analysis of the loads in the real car. Finally, the paper will show the actual comparison with the traditional BEC and the smart BEC in terms of weight, size, power loss, wiring saving, and cost in the real car.
Tian, Xia, Shen, Ning, Wang, Xingwei
Numerical Investigation of Wiper Drawback2019-01-06404/2/2019
Windscreen wipers are an integral component of the windscreen cleaning systems of most vehicles, trains, cars, trucks, boats and some planes. Wipers are used to clear rain, snow, and dirt from the windscreen pushing the water from the wiped surface. Under certain conditions however, water which has been driven to the edge of the windscreen by the wiper can be drawn back into the driver’s field of view by aerodynamic forces introduced by the wiper motion. This is wiper drawback, an undesirable phenomenon as the water which is drawn back on to the windscreen can reduce driver’s vision and makes the wiper less effective. The phenomena of wiper drawback can be tested for in climatic tunnels using sprayer systems to wet the windscreen. However, these tests require a bespoke test property or prototype vehicle, which means that the tests are done fairly late in the development of the vehicle. Furthermore, these results do not provide significant insight into the mechanisms driving the wiper drawback. In order to better understand wiper drawback a numerical simulation is presented of a configuration known to exhibit this phenomenon. This requires the inclusion into an aerodynamics solver of: moving wipers, a surface film model, and a representation of airborne spray. Using the results of this simulation, the forces causing the drawback of the water film, along with the mechanism for introducing these forces are studied. Through understanding the driving factors in wiper drawback, it can be avoided earlier in the development cycle.
Jilesen, Jonathan, Gaylard, Adrian, Linden, Tom
Investigation of Drag Reduction Technologies for Light-Duty Vehicles Using Surface, Wake and Underbody Pressure Measurements to Complement Aerodynamic Drag Measurements2019-01-06444/2/2019
A multi-year, multi-vehicle study was conducted to quantify the aerodynamic drag changes associated with drag reduction technologies for light-duty vehicles. Various technologies were evaluated through full-scale testing in a large low-blockage closed-circuit wind tunnel equipped with a rolling road, wheel rollers, boundary-layer suction and a system to generate road-representative turbulent winds. The technologies investigated include active grille shutters, production and custom underbody treatments, air dams, wheel curtains, ride height control, side mirror removal and combinations of these. This paper focuses on mean surface-, wake-, and underbody-pressure measurements and their relation to aerodynamic drag. Surface pressures were measured at strategic locations on four sedans and two crossover SUVs. Wake total pressures were mapped using a rake of Pitot probes in two cross-flow planes at up to 0.4 vehicle lengths downstream of the same six vehicles in addition to a minivan and a pick-up truck. A smaller rake was used to map underbody total pressures in one cross-flow plane downstream of the rear axle for three of these vehicles. The results link drag reduction due to various technologies with specific changes in vehicle surface, rear underbody and wake pressures, and provide a database for numerical studies. In particular, the results suggest that existing or idealized prototype technologies such as active grille shutters, sealing the external grille and ride height control reduce drag by redirecting incoming flow from the engine bay or underbody region to smoother surfaces above and around the vehicle. This mechanism can enhance the reduction in wheel drag due to reduced wheel exposure at lowered ride height. Sealing the external grille was found to redirect the flow more efficiently than closing the grille shutters, and resulted in greater drag reduction. Underbody treatments were also found in some cases to redistribute the flow around the vehicle to reduce pressure drag in addition to underbody friction drag. The magnitude and spatial extent of the measured pressure changes due to the various technologies were often consistent with the amount of drag reduction.
de Souza, Fenella, Raeesi, Arash, Belzile, Marc, Caffrey, Cheryl, Schmitt, Andreas
Nissan Leaf finally gets more range19AUTP04_174/1/2019
The 2019 Leaf Plus has a longer driving range and provides quicker acceleration than its platform-sharing counterpart, the second-generation Leaf, thanks to a higher-output motor and additional battery cells. Nissan's most-powerful electric car yet claims a 226 mi (321 km) driving range, outpacing the standard Leaf's 150 mi (241-km) driving range. The Leaf Plus is in league with other longer-range EVs, including the Chevrolet Bolt, Hyundai Kona and Tesla Model 3. All Leaf models (first introduced in MY2011) package lithium-ion batteries under the floor between the axles. “The key engineering challenge for us was adding 50% more battery capacity into an existing packaging space,” said Nathan Herbrandson, North American program development manager for the Leaf, during a recent Leaf Plus media intro in southern California. The Leaf's 40-kW·h battery pack has two layers of modules (192 cells), while the Leaf Plus's 62-kWh pack has three layers of modules (288 cells).
Buchholz, Kami
Multiplexing of Wireless Surface Acoustic Wave SensorsTBMG-341584/1/2019
The traditional approach for wireless sensors involves interrogators that communicate with each other (i.e., the two boxes “talk” to each other). In contrast, surface acoustic wave (SAW) sensors allow for a single box that can communicate with multiple sensors. One of the biggest advantages of SAW sensors over competing wireless sensors is that the SAW sensors do not require a power source.
Text Tech: Navy Vessels Use Shipboard Signal Lamps for Text MessagingTBMG-338933/1/2019
Sponsored by the Office of Naval Research's (ONR) TechSolutions program, the Flashing Light to Text Converter (FLTC) features a camera that can be mounted atop a signal lamp to receive Morse code bursts from another lamp within view. A hand-held device or laptop computer is connected to this camera to display text messages sent and received.
Aircraft Deicing Vehicle - Self-PropelledARP1971D (Current)2/13/2019
This SAE Aerospace Recommended Practice (ARP) covers requirements for a self-propelled, boom-type aerial device, equipped with an aircraft deicing/anti-icing fluid spraying system. The unit shall be highly maneuverable for deicing all exterior surfaces of commercial aircraft, of sizes agreed upon between purchaser and manufacturer, in accordance with AS6285. The vehicle shall be suitable for day and night operations.
G-12E Equipment Committee
Virtual Simulation of Door Slam Test, Study of Relative Sensitive Parameters and Correlation with Physical Test2019-26-02751/9/2019
Door slam test is one of the important durability tests in door design and development. Door requires to meet certain performance requirements like it should close properly (no metal to metal contact), there should not be any leakage, and closing operation should be smooth & with minimal effort and it should survive the life of the vehicle. Virtual simulation of door slam test, correlation with physical test results and effect of various parameters like seals stiffness are demonstrated in this study. Slam Analysis was carried out in LS-Dyna solver before physical test. This not only helped in avoiding initial structural design flaws, but also helped us in deciding door latch position, effect of mass distribution in the door and study of force distribution between primary seal, secondary seal and door latch. Primary and secondary seals played a critical role in the analysis. An intended length of both the seals was tested first to get its stiffness curve. Then it was modeled in the way that stiffness of one beam represented the stiffness of testing length. An in-house developed physical test was carried out for the intended cycles. A good correlation between simulation and test results is achieved. Overall detailed study of door slam test, simulation methodology and effect of various relative parameters on performance has become very important step in design and development of door assembly.
Shrivastava, Rishi, Dhole, Avinash, Raval, Chetan
A Test Methodology for Vehicle Wind Noise Reduction and Acoustic Quality Improvement2019-26-02161/9/2019
Aeroacoustics of vehicles is becoming an important design criterion as it directly affects passenger’s comfort. The wind noise at highway speeds (>80 KMPH) is a critical quality concern under normal and crosswind conditions and dominant factor in assessing acoustic comfort of the vehicle. Wind noise is caused by the vortex air flow around a vehicle body and air leakage through the sealing gaps of attached parts. This majorly contributes to high frequency noise (>250 Hz). Accurate identification and control of noise sources and leakage paths result in improved acoustic comfort of the vehicle. In this paper, aero-acoustic quality characteristics of validation prototype vehicle are studied. The major wind noise sources and leakage paths in the vehicle are identified through in-house blower set up in the semi anechoic room. The overall wind noise level and articulation index of vehicle at various speeds are determined through on- road measurements. The improvement in the vehicle articulation index (AI) by 14% and reduction in noise level by 4 dB (A) are achieved through design modification of seals, door structure and trim parts.
Mukkera, Swamy, Raamya Premkumar, Senthilkumar, Samar, Deshpande, R, Prasath
3D Printer Creates Complex Biological TissuesTBMG-335971/1/2019
A technique was developed that uses a specially adapted 3D printer to build therapeutic biomaterials from multiple materials. The advance could be a step toward on-demand printing of complex artificial tissues for use in transplants and other surgeries.
Development of a CAE Method for Predicting Solar Loading Impact for Electrical System Performance in an Automotive Cabin2018-01-07854/3/2018
A number of market factors such as customer demand for improved connectivity and infotainment systems, automated driver assist systems and electrification of powertrain have driven an increase in the number of electrical systems within the cabin of automotive vehicles. These systems have limited operating temperature windows, therefore markets with high ambient temperatures and solar loading represent a significant challenge due to high cabin temperatures. Traditionally climatic facilities have been used replicate the conditions seen in these markets in order to understand the performance of the electrical systems. However such facilities have a number of limitations such as fixed solar arrays, secondary radiation from the walls and substantial operating costs limiting testing to envelope tests. Therefore the requirement for CAE based approach to more accurately represent the conditions seen in the real world is clear. To this end this work presents a CAE method for predicting component and ambient temperatures within the cabin. To improve the understanding of the effect environmental factors have on cabin temperatures and to correlate the computational results an experimental methodology has been developed to collect in-field data. The key features of the test procedure include comprehensive instrumentation of vehicle cabin to measure ambient and surface temperatures, characterization of the ambient conditions local to the vehicle including; direct, diffuse and global solar irradiance, temperature, wind speed and direction. The results generated by the computational model have been also been correlated against those collected from the climatic wind tunnel to ensure robust behavior. A comparison of the temperature distributions for the real world and wind tunnel datasets is presented to determine the validity of wind tunnel testing.
Palmer, Edward W., Jansen, Wilko, Palaniswamy, Adaikala, Parfitt, Megan
Evaluation and Improvement of Greenhouse Wind Noise of a SGMW SUV using Simulation Driven Design2018-01-07374/3/2018
At SAIC-GM-Wuling (SGMW) the greenhouse wind noise performance of their vehicles has gained a lot of attention in the development process. In order to evaluate and improve the noise quality of a newly developed SUV a digital simulation based process has been employed during the early stage of the design. CFD simulation was used for obtaining the flow induced exterior noise sources. Performance metrics for the quality were based on interior noise levels which were calculated from the exterior sources using a SEA approach for the noise transmission through the glass panels and propagation to the driver’s or passenger’s head space. Detailed analysis of the CFD results allowed to identify noise sources and related flow structures. Based on this analysis, design modifications were then applied and tested in a sequential iterative process. As a result an improvement of more than 2 dB in overall sound pressure level could be achieved.
Hou, Zhaoping, Fu, Nian, Huang cEng, Yuanyi, Lv, Juncheng, Shen, Yantao, Huang, Hongyan, Wu, Long, Xie, Weiliang, Friz, Heinz
On the Aerodynamics of an Enclosed-Wheel Racing Car: An Assessment and Proposal of Add-On Devices for a Fourth, High-Performance Configuration of the DrivAer Model2018-01-07254/3/2018
A modern benchmark for passenger cars - DrivAer model - has provided significant contributions to aerodynamics-related topics in automotive engineering, where three categories of passenger cars have been successfully represented. However, a reference model for high-performance car configurations has not been considered appropriately yet. Technical knowledge in motorsport is also restricted due to competitiveness in performance, reputation and commercial gains. The consequence is a shortage of open-access material to be used as technical references for either motorsport community or academic research purposes. In this paper, a parametric assessment of race car aerodynamic devices are presented into four groups of studies. These are: (i) forebody strakes (dive planes), (ii) front bumper splitter, (iii) rear-end spoiler, and (iv) underbody diffuser. The simplified design of these add-ons focuses on the main parameters (such as length, position, or incidence), leading to easier manufacturing for experiments and implementation in computational studies. Consequently, a proposed model aims to address enclosed-wheel racing car categories, adapting a simplified, 35% scaled-model DrivAer Fastback shape (i.e. smooth underbody, no wheels, and with side mirrors). Experimental data were obtained at the 8 ft x 6 ft Cranfield Wind Tunnel using an internal balance for force and moment measurements. The aerodynamic performance of each group of add-on was assessed individually in a range of ride heights over a moving belt. All cases represent the vehicle at a zero-yaw condition, Reynolds number (car length-based) of 4.2 × 106 and Mach number equal to 0.12. The proposed high-performance configuration (DrivAer hp-F) was tested and a respective Reynolds number dependency study is also provided. In line with the open-access concept of the DrivAer model, the CAD geometry and experimental data will be made available online to the international community to support independent studies.
Soares, Renan Francisco, Knowles, Andrew, Goñalons Olives, Sergio, Garry, Kevin, Holt, Jennifer
Investigation of Interior Noise from Generic Side- View Mirror Using Incompressible and Compressible Solvers of DES and LES2018-01-07354/3/2018
Exterior turbulent flow is an important source of automobile cabin interior noise. The turbulent flow impacts the windows of the cabins to excite the structural vibration that emits the interior noise. Meanwhile, the exterior noise generated from the turbulent flow can also cause the window vibration and generate the interior noise. Side-view mirrors mounted upstream of the windows are one of the predominant body parts inducing the turbulent flow. In this paper, we investigate the interior noise caused by a generic side-view mirror. The interior noise propagates in a cuboid cavity with a rectangular glass window. The exterior flow and the exterior noise are computed using advanced CFD methods: compressible large eddy simulation, compressible detached eddy simulation (DES), incompressible DES, and incompressible DES coupled with an acoustic wave model. The last method is used to simulate the hydrodynamic and acoustic pressure separately. The pressure fluctuations of the flow and noise are imposed on the window in the computation of the interior noise, but the reversal effect of the window vibration feeding back on the flow is neglected in the flow simulation. The localized flow characteristics are discussed. The energetic surface pressure appears in the regions where the shear layer from the mirror side edge impinges on the window. The contributions of the hydrodynamic and acoustic pressure to the interior noise are quantified. The acoustic component is found to be more efficient in the interior noise generation and to play the dominant role at high frequencies.
Yao, Huadong, Davidson, Lars, Chroneer, Zenitha
Simplifications Applied to Simulation of Turbulence Induced by a Side View Mirror of a Full-Scale Truck Using DES2018-01-07084/3/2018
In this paper, the turbulent flow induced by a production side-view mirror assembled on a full-scale production truck is simulated using a compressible k-ω SST detached eddy simulation (DES) approach -- the improved delayed DES (IDDES). The truck configuration consists of a compartment and a trailer. Due to the large size and geometric complexity of the configuration, some simplifications are applied to the simulation. A purpose of this work is to investigate whether the simplifications are suitable to obtain the reasonable properties of the flow near the side-view mirror. Another objective is to study the aerodynamic performances of the mirror. The configuration is simplified regarding two treatments. The first treatment is to retain the key exterior components of the truck body while removing the small gaps and structures. Furthermore, the trailer is shaped in an apex-truncated square pyramid. This simplification is proposed based on the assumption that the downstream flow near the trailer has limited effect on the flow near the mirror. To assess the influences of the simplifications, the flow fields computed from the original and simplified configurations are compared. The regions on the window that are subjected to significant hydrodynamic impingement are identified. The mirror and A-pillar introduce the impingement. The frequency spectra of the surface pressure fluctuations on the window are studied. The frequencies of the peaks in the spectra are the same as the characteristic frequencies of the free shear layers that develop from the mirror side-edges near the window. The simplifications are found as feasible treatments to reproduce the flow characteristics of the original geometry.
Yao, Huadong, Chroneer, Zenitha, Davidson, Lars
Optimal Study on the TL of Automotive Door Sealing System Based on the Interior Speech Intelligibility2018-01-06724/3/2018
Wind noise becomes the foremost noise source when a car runs at high speeds. High frequency characteristics of wind noise source and effective performance of seal rubbers for insulating leakage noise make research on the Transmission Loss (TL) of automotive door sealing systems significant. The improvement of TL of automotive door sealing system could effectively decrease the interior noise due to wind noise for vehicles at high speeds. In this study, compression simulation of seal rubbers for an automotive door is performed through a Finite Element (FE) tool firstly. Compressed geometries of the seal rubbers are obtained. Then, based on the final compressed geometries and pre-stress modes of the automotive door seal rubbers, the TL of the whole door sealing system is acquired by hybrid Finite Element - Statistic Energy Analysis (FE-SEA) method. The fluctuating surface pressure on a car body was captured by a Computational Fluid Dynamics (CFD) tool. The wind noise source is obtained by the Corcos model and the Boundary Element Method (BEM). A full vehicle SEA model is built to predict the interior sound pressure level. The TL of the automotive door sealing system is included in the full vehicle SEA model. After the SPL in the car is obtained by SEA simulation, the Articulation Index (AI) is calculated. Finally, the TL of the automotive door sealing system is optimized by orthogonal design of experiment based on AI. This integrated approach can be used to optimize TLs of automotive door sealing systems.
Deng, Guoming, Zheng, Songlin, Wu, Xian, Shao, Jianwang, Zhao, Meng
Tiny Terahertz Laser for Imaging and Chemical DetectionTBMG-285053/1/2018
Terahertz radiation — the band of the electromagnetic spectrum between microwaves and visible light — has promising applications in medical and industrial imaging and chemical detection, among other uses. But many of those applications depend on small, power-efficient sources of terahertz rays, and the standard method for producing them involves a bulky, power-hungry, tabletop device.
Fourier Transform Spectrometer SystemTBMG-283362/1/2018
NASA's Langley Research Center and Science Applications International Corporation have developed a method of processing data from Fourier transform spectroscopy (FTS) measurements that improves upon existing methods. This method is simpler, more accurate, faster, and less expensive than previous methods. It uses less hardware and can be used with all wavelengths.
Webb Telescope Actuators Move with Microscopic AccuracyTBMG-2794812/1/2017
The James Webb Space Telescope will be the most powerful space telescope ever built. With a 21-foot diameter, the telescope’s primary mirror is six times larger than the one used by the Hubble Space Telescope. In order for such a large mirror to travel into space, it has to be broken up into multiple segments; in this case, 18 of them. But for the 18 to act as one primary mirror, they have to be adjusted while in orbit.
Wallops Arc-Second Pointer (WASP)TBMG-2802412/1/2017
The Wallops Arc Second Pointer (WASP) is a balloon-borne attitude control system capable of pointing a telescope or instrument with accuracy and stability down to the arc second, or 1/3600 of a degree of angular measurement. When a high-powered telescope is integrated with WASP, it provides a highly precise platform for conducting astronomical research. To date, the WASP system has been tested aboard five helium-filled scientific balloons at altitudes between 100,000 – 125,000 feet with flight durations up to 15 hours. During these pathfinder missions, the WASP controlled instrument structures with masses between 1,000 – 2,000 lbs.
Electrochemically Enhanced Mechanical Polishing of OpticsTBMG-2801412/1/2017
NASA’s Marshall Space Flight Center astrophysicists are developing better instruments to measure high-energy X-rays zipping about space when viewed from above the Earth’s atmosphere. Scientists at MSFC adapted a novel method for material removal and super-polishing to the mandrel fabrication of an advanced X-ray telescope.
Diffusion-Bonded CVC SiC for Large UVOIR Telescope Mirrors and StructuresTBMG-2780011/1/2017
In 2012, the National Research Council called for a new generation of astronomical telescopes to enable discovery of habitable planets, facilitate advances in solar physics, and enable the study of faint structures around bright objects by developing high-contrast imaging and spectroscopic technologies to provide unprecedented sensitivity, field of view, and spectroscopy of faint objects. Large-aperture, lightweight mirrors for UV, Optical and IR (UVOIR) telescopes answer this need. NASA requires low-cost, ultra-stable, large-aperture, normal incidence mirrors with low mass-to-collecting-area ratios. Potential UV/optical missions require 4- to 8- or 16- meter monolithic or segmented primary mirrors with active/passive alignment and control of normal-incidence imaging systems with <10 nm RMS surface figures.
NEW VISION @ GENTEX17AUTP09_019/1/2017
Creating a vital ADAS partner through home-grown R&D and manufacturing in (of all places) western Michigan. On first glance, it appears to be a passive rectangle of reflective glass. But the full-display mirror, or FDM as its maker Gentex Corp. calls it, comes alive when you start the vehicle. In the Cadillac CT6, XT5 and Chevrolet Bolt EV where it debuted in 2016, the FDM pulls an image from a rear mounted, high-definition camera and streams it onto an LCD display embedded in the mirror module. The result is a high-value safety feature: enhanced, real-time video of the scene behind the vehicle. It's presented in a 40° field of view-more than double the lateral scope of a traditional optical rearview mirror. Because the driver is actually seeing through the rear-mounted camera, the FDM makes the vehicle's roof pillars and rear seat head rests disappear to the eye. The view is unobstructed.
Brooke, Lindsay
New Microscope Uses Adaptable Mirror to Create Clearer ImagesTBMG-275679/1/2017
The National Institute of Biomedical Imaging and Bioengineering (NBIB) has developed a microscope that increases resolution and contrast in thick biological samples. The new microscope improves on its predecessor by combining two-photon laser scanning microscopy (2PM) with instant structured illumination microscopy (ISIM). Key to the development, was including adaptive optics (AO) to rapidly correct distortions.
High-Power Broadband Multispectral Source on a Hybrid Silicon ChipTBMG-274939/1/2017
For applications in manufacturing, remote sensing, medicine, military, and fundamental science, an ideal laser would have high output power and a diffraction-limited beam. The figure-of-merit to describe this property is the brightness, which scales proportional to output power and inverse to the beam quality factor M2.
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