Browse Topic: Molding

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Multi-objective Optimization of Rotorcraft Blade Structure with Multi-disciplinary ConstraintsF-0081-2025-03385/20/2025
We extend the previously developed integrated VABS (iVABS) framework for rotor blade structural optimization with an enhanced cross-section template for practical manufacture considerations; these include the introduction of curved spar corners, a continuous wrap-around skin, trailing-edge tabs and a conformal non-structural mass. The added fidelity is exercised on a UH-60A-based outer mold line through three multi-objective optimization case studies, including a case where the cross-sections are optimized independent of each other, and two cases where all the cross-sections are optimized simultaneously with manufacture considerations. It was found that the latter cases produce straight spars that are relatively more practical to manufacture when compared to the first case, while achieving significant reduction of up to 80% in the mismatch of stiffness values, inertia properties, and shear center locations, when compared to the prior work. A subsequent sensitivity analysis of the Pareto set isolates five critical combinations of design variables, out of the original nearly 100 variables, such as root/mid-span skin-ply count and spar-web placement, that can be adjusted to refine the Pareto solution. The study demonstrates that manufacturability-aware parameterization and data-driven variable reduction can deliver practical composite-blade designs within a scalable optimization loop.
Song, Jiwoo, Zhang, Jianhua, Smith, Edward, Haehnel, Robert, Huang, Daning
Bars, Rods, and Shapes Produced from Unfilled Polyamide-Imide (PAI) MaterialAMS3670/1C (Current)5/19/2021
This specification covers an unfilled polyamide-imide plastic in the form of molded or extruded bar, rod, and shapes. This is designated as Grade 2 material per AMS3670.
AMS P Polymeric Materials Committee
Engineers Design a Reusable, Silicone Rubber Face MaskTBMG-373598/1/2020
Researchers at MIT and Brigham and Women’s Hospital have designed a new face mask that they believe could stop viral particles as effectively as N95 masks. Unlike N95 masks, the new masks were designed to be easily sterilized and used many times.
JLR tackles weight with structural electronics20AUTP03_103/1/2020
Ashutosh Tomar, electrical research technical manager at Jaguar Land Rover (JLR) said he has absolute confidence in the potential of structural electronics (SE) now being pioneered by the company. Dubbed LESA (Lightweight Electronics in Simplified Architecture), the technology is expected in upcoming JLR models, though its use in the next-generation Jaguar XJ to be launched in 2020 has not been confirmed. JLR is completing a successful R&D program into printed SE, initially to introduce curved dashboard screens. The company claims an industry first that has the potential to radically alter vehicle interiors, with other applications forthcoming. SE is not a new technology. Decades ago the aerospace industry was considering it as part of aircraft-surface morphing capability to adapt to varying flight conditions.
Birch, Stuart
Q&A: Solid Silk - A Biocompatible, Sustainable, Degradable Building BlockTBMG-361753/1/2020
David Kaplan, Stern Family Professor of Engineering at Tufts University’s College of Engineering, and his team have developed a unique and practical method for processing silk into solid form for products such as rods and plates for medical implants.
Reducing Risk with Geometric Transition ExtrusionTBMG-3549811/1/2019
In an effort to design smaller, more intricate and complicated medical devices without running afoul of increasingly stringent national and international regulations, many designers are looking to geometric transition extrusions manufactured of high consistency rubber (HCR) silicone. This process reduces total cost of ownership for the original equipment manufacturer while improving part quality and greatly enhancing the types of devices being sought by healthcare providers.
Customer Challenges Lead to Innovative SolutionsTBMG-3533610/1/2019
Contract manufacturers have an increasingly critical role in medical device manufacturing. For original equipment manufacturers (OEMs) that choose to outsource manufacturing operations, a successful contract manufacturing organization (CMO) partnership can help ensure that a new product will reach the market sooner, achieve financial success, and deliver high-quality innovation to end users.
Polyamide Type 6-6, Plastic Moldings and ExtrusionsAMS3617F (Current)6/13/2019
This specification covers one type of Polyamide Type 6-6 (nylon) thermoplastic resin in the form of moldings and extrusions.
AMS P Polymeric Materials Committee
Model Gives Robots a Better Feel for Object ManipulationTBMG-345766/1/2019
A new learning system improves a robot’s ability to mold materials into target shapes and make predictions about interacting with solid objects and liquids. The system, known as a learning-based particle simulator, could give industrial robots a more refined touch and may have applications in personal robotics.
Why Reel-to-Reel Molding Might Be Right for Medical ComponentsTBMG-344485/1/2019
Reel-to-reel insert molding can prove a more efficient process for design engineers when it comes to lowering assembly costs. The process is best suited for products that require dimensional stability and need to function in harsh environments, such as drug-delivery device parts and components.
Digital Manufacturing Helps Medtech Firm's Goal to Improve Patient OutcomesTBMG-342614/1/2019
As often happens in the medical industry, innovative ideas hatched in university research settings spawn innovative companies, which create innovative products. A case in point: HemoSonics. The Charlottesville, VA-based medical device company was started in 2005 by two professors and a post-doctoral research student at the University of Virginia School of Medicine's Bio-Medical Engineering program — Bill Walker, Mike Lawrence, and Francesco Viola, respectively. The trio identified a method for measuring the stiffness of blood clots by using ultrasound imaging technology and created a system built around that technology aimed to improve patient outcomes and reduce costs.
Interactive Software Simplifies Complex Mold DesignTBMG-336812/1/2019
Molding is a popular method for the mass production of objects. Essentially, two (or more) mold pieces are fit together, leaving the shape of the desired object as a hole. During fabrication, a fluid is introduced into this cavity and is allowed to harden. Once the fluid has solidified, the pieces of the mold are removed, leaving behind the molded object. While the process is fairly simple, creating the mold to produce an object is extremely difficult, and a multitude of considerations go into its creation.
Nickel Alloy, Corrosion and Heat-Resistant, 47.5Ni - 22Cr - 1.5Co - 9.0Mo - 0.60W - 18.5Fe Powder for General Applications including Metal Injection Molding and Additive Manufacturing without Special Powder Manufacturing ControlsAMS5924 (Current)1/14/2019
This specification covers a corrosion and heat-resistant nickel-chromium-iron-molybdenum-alloy in the form of pre-alloyed powder manufactured by atomization in an inert gas.
AMS F Corrosion Heat Resistant Alloys Committee
Design for Manufacturing: Tips for Molding Components in SiliconeTBMG-335601/1/2019
Device functionality is usually the starting point when designing devices. Another element that needs to be considered when designing devices and their subsequent components is their manu-facturability. Part design should also be focused on the ease of manufacturing because it can help reduce cost and lead to a robust and reliable process. Several aspects should be considered regarding manufacturabil-ity: part geometry, location, and size and shape of critical surfaces, among others. These may seem like more obvious characteristics, but there are a few others that can be overlooked, but should be considered just as important. These are material selection, dimensioning/tolerancing, and the selection of critical dimensions. To better understand the impact of these factors, this article explores each characteristic in detail.
Compression Molding PressTBMG-3336312/1/2018
Beckwood Press Company Fenton, MO 636-343-4100
MIM and 3D Printing: Precision Cleaning and Product Finishing of Medical DevicesTBMG-3325111/1/2018
As the miniaturization trend continues to take the medical device world by storm, manufacturing with metal injection molding (MIM) and additive processes such as 3D printing are gaining widespread acceptance, allowing designers more options for creating parts economically that would otherwise be impossible to manufacture. In many instances, these state-of-the-art MIM and 3D printed processes are not possible without the use of special cleaning and or solvent-based process treatments.
Metal Tubing Offers Flexibility for Disposable DevicesTBMG-3325811/1/2018
Traditional handheld surgical tools continue to provide benefits where surgeons need instruments to be more rigid and have strong holding power to withstand complex procedures. The majority of these small handheld devices include tubing technology. Those made with metal can be formed to meet specific needs. Base tubing can be created from drawn tubing or from flat sheets of metal in a patented technique known as rolled-tube technology, which is ideal for creating high volume disposable devices.
Ensuring Injection Molding Quality for Medical DevicesTBMG-3308910/1/2018
Plastics are incredibly versatile. There are thousands of types available to satisfy a myriad of medical applications. Yet, certain plastics present special challenges during the injection molding process that — if not properly addressed — can impact product quality and ultimately preclude medical devices from meeting exacting specifications. The medical device or component cannot — and must not — fail. To do otherwise increases the risk of recall, warranty claims, and litigation. In worst-case scenarios, failure may prove lethal.
Research Collaboration Could Reshape Injection MoldingTBMG-3308810/1/2018
As Ralph Colby peers at the microscope image in front of him, he thinks he can make them out — “shish kebabs,” as polymer scientists call them. Nobody knows for sure what they are, but these shapes that appear at seemingly unpredictable times when certain plastics cool have a big impact on the overall properties of plastics. It's not a big deal when a plastic fork breaks, but if a bearing cage on an airplane were to break, it could put people in danger.
Tests Prove Immersion Method of Production of Implantable Devices is EffectiveTBMG-328189/1/2018
Healthcare-associated infections (HAI) are a major, yet often preventable threat to patient safety, and they can have a significant impact on the survival rate of patients who undergo procedures and treatments. In particular, catheter-associated infections are difficult to prevent, even when products are made of silicone, due to their inherent positioning both inside and outside of the body.
Material Advances for Additive Manufacturing of Bioresorbable Polymeric Medical DevicesTBMG-289185/1/2018
Although we’ve heard a lot about the promise of additive manufacturing (AM), the reality is that this technology has not yet caused a revolution in medical device manufacturing. But there is a slowly forming niche of AM medical devices that relies on the combination of advanced design, processing, and innovative materials to create customized solutions.
Two-Component Molding Can Solve Medical Design Challenges and Reduce CostsTBMG-289255/1/2018
Device manufacturers count on their supply chain partners for answers. What can be adjusted, how can we add value, and what methods can be used to streamline manufacturing processes, reduce SKUs, and improve part quality? One way is by moving from single-component molding to two-component molding.
Carbon Fiber/Epoxy Mold with Embedded Carbon Fiber Resistor Heater - Case Study05-11-02-00114/7/2018
The article presents a complete description of the design and manufacturing of a Carbon Fiber/epoxy mold with an embedded Carbon Fiber resistor heater, and the mold performances in terms of its surface temperature distribution and thermal deformations resulting from the heating. The mold was designed for manufacturing aileron skins from Vacuum Bag Only prepreg cured at 135°C. The glass transition temperature of the used resin-hardener system was about 175°C. To ensure homogenous temperature of the mold working surface in the course of curing, the Carbon Fiber heater was embedded in a layer of a highly heat-conductive cristobalite/epoxy composite, forming the core of the mold shell. Because the cristobalite/epoxy composite displayed much higher thermal expansion than CF/epoxy did, thermal stresses could arise due to this discrepancy in the course of heating. Therefore, to lower these stresses, the Carbon Fiber/epoxy faces were separated from the cristobalite/epoxy core containing the heating element by the buffer layer of carbon nanotubes/epoxy displaying intermediate thermal expansion. The determined mold surface thermal deformation was in the range of 1 mm in 20°C-135°C temperature range and, at 135°C, the mold surface temperature unevenness was in the range of 10°C. Despite such temperature unevenness, the Tg values determined with the help of the specimens cut out from the different parts of the cured skin were of satisfactory values.
Czarnocki, Piotr, Boczkowska, Anna, Frączek, Wojciech, Chabera, Paulina, Kubis, Michał, Marjanowski, Jędrzej
Microextrusion Tubing Advances Help Push Medical Device BoundariesTBMG-285203/1/2018
Over the past five years, technological advances have enabled product applications for microextrusion to penetrate into the medical OEM arena. Simply speaking, micro now really means micro. Years ago, when an OEM was asking for micro tubing, they typically were looking for ranges between 0.060 and 0.100 in. OD with 2-4 lumens. Now micro range dimensions are down to 0.024 in. OD with up to 6 lumens, including an ID range as low as 0.003 in.
Vote for Medical Design Briefs Annual Readers' Choice AwardsTBMG-2807012/7/2017
Each month, the editors of Medical Design Briefs choose a Product of the Month that has exceptional technical merit and practical value for MDB’s design engineering readers.
Vacuum System Powers Modular Soft RobotTBMG-2794012/1/2017
Researchers at the Ecole Polytechnique Federale de Lausanne (EPFL) have created the first functional robot powered entirely by vacuum. It is made of soft building blocks that move by having air sucked out of them. The robot can be reconfigured to perform different tasks, like climbing vertical walls and grabbing objects.
Optimizing Performance and Value of Medical Devices with the Right Plastic Processing TechnologyTBMG-2797612/1/2017
Application of Six Sigma Methodology to Improve Product Quality in Injection Molded Parts at Supplier End in Motorcycle Industry2017-01-50119/29/2017
Process Parameters play a vital role in product quality of Injection Molded components. Variation in process parameters will lead to Injection Molded manufacturing defects like Sink Mark, Flow Mark, Silver Streak, Flash, Warping, Weld lines, Jetting, voids, Short Shot & Bubbles. This manuscript is innovative because suppliers (Tier 1 and Tier 2) do not use DoE for standardization of their process parameters in Injection Molding and High Pressure Die Casting. They do trial and error method to arrive at the process parameters which is error prone and time consuming. The variation of process parameters can be optimized using Six Sigma approach, a structured methodology which is Process focused & data driven approach. The purpose of this paper is to present through a case study how the concepts of Design of Experiments, which is a part of Six Sigma Methodology can be used for improving the Injection Molding Process at supplier end reducing defects & hence improving Quality at supplier which stops 100% BOP inspection and segregation when the parts reach the OEM. Here one of the products in Motorcycle Industry has been taken which has 100% Sink Mark defect & resulting in 100% rework. By following the six sigma DMAIC approach and using tools like SIPOC, PMAP, Fish Bone Diagram, Cause and Effect Matrix & Design of experiments to optimize the process parameters at supplier Injection Molding Machine through cross functional team approach. The result has proved that the quality of the product in automotive Industry can be improved by using Six Sigma Approach. This approach can be used for all suppliers and all OEMs or can be horizontally deployed in the Injection Molding Process and High Pressure Die Casting Process to reduce defects and improve product quality by reducing process variation.
Shankaranarayana, Raviprakash
Dr. Keiko Munechika, Manager, Nanofabrication, aBeam Technologies, Hayward, CATBMG-274078/21/2017
Dr. Munechika — along with Alexander Koshelev and Giuseppe Calafiore at aBeam Technologies, and Stefano Cabrini at the Molecular Foundry at Lawrence Berkeley National Laboratory — is developing a process that would enable widespread adoption of nano-optic technology. The team perfected a technique for fabricating a Campanile probe, whose tapered, four-sided shape resembles the top of the Campanile clock tower on UC Berkeley’s campus. The probe focuses an intense beam of light onto a much smaller spot than is possible with current optics.
Linear Fresnel Spectrometer Chip with Gradient Line GratingTBMG-272918/1/2017
NASA's Langley Research Center has built a very small spectrometer by integrating a differential linear Fresnel lens onto an imaging chip. NASA is using the lens/chip in a very small spectrometer that will be mounted on the tires of a rover to analyze soil on the Moon or Mars. The spectrometer is useful for space-constrained applications. It combines good resolution with small size and potentially reduced manufacturing costs. The ultra-compact integration of the spectrometer is enabled by the use of an optimized Fresnel grating. Since Fresnel imaging works as valid focal points of spectrum within the short optical distance, the shorter optical path length required (compared to a traditional Fraunhofer lens) enables the small size. Further, the evolution to a differentially linear Fresnel lens (instead of circular Fresnel) avoids the need for aperture slit driver electronics and moving parts, and simplifies manufacturing. The linear Fresnel gratings lend themselves to mass production via plastic injection molding or nano-imprint lithography. NASA is seeking partners to develop the spectrometer for commercial applications.
Adam Sidor, NASA Research Fellow, Georgia Institute of Technology, Atlanta, GATBMG-271026/20/2017
Thermal Protection Systems (TPS) — heatshields — form the outer surface of spacecraft and provide protection as the vehicle plunges through planetary atmospheres. Conformal ablative materials are currently being developed to improve TPS performance. Adam Sidor is developing a fresh approach to designing and manufacturing these materials to produce larger tile sizes while reducing labor, cost, and waste.
Polyimides Derived from Novel Asymmetric Benzophenone DianhydridesTBMG-268515/1/2017
NASA's Glenn Research Center invites companies to license or establish partnerships to develop its patented high-temperature, low-melt imide resins for fabrication of automotive components. Produced by a solvent-free melt process, these resins exhibit high glass transition temperatures (Tg = 370 to 400 °C), low melt viscosities (10 to 30 poise), long pot-life (1 to 2 hours), and can be easily processed by low-cost RTM and vacuum-assisted resin transfer molding (VARTM). These RTM resins melt at 260 to 280 °C, and can be cured at 340 to 370 °C in 2 hours without releasing any harmful volatile compounds.
Nanotubular Toughening InclusionsTBMG-268825/1/2017
NASA's Langley Research Center has developed an extensive technology portfolio on novel methods for effective dispersion of carbon nanotubes (CNTs) in polymers. The technology portfolio extends from making stable dispersions of CNTs in polymer resins to processes for making composite CNT/polymer films and articles. The technologies apply to a range of polymer types, enable low or high CNT loadings as needed, and can be used with a variety of standard polymer processing methods, including melt processing. Currently, the technology is being used commercially for electrically conductive polymer films for components in electronic printers and copiers.
CABLE ASSEMBLY, EXTERNAL ELECTRIC POWER, AIRCRAFT 28 VOLT DC, OPERATING POWERAS90347A (Historical)11/12/2016
AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
Application of Rapid Heat and Cool Molding to High Strength Outer Parts without Painting Treatment2016-32-002411/8/2016
Glass fiber reinforced plastic of polyamide is applied as one of the materials used for the high strength exterior parts of a motorcycle, such as a rear grab rail or a carrier, to which both strength and good exterior appearance are required. However, Glass Fiber reinforced Polypropylene (PPGF), which is relatively inexpensive material, has a property that the contained glass fibers are prone to be exposed at the surface and, therefore, the requirements for good appearance are hardly met by using PPGF. In this study, Heat and Cool molding method (H&C molding) was employed to realize a cost reduction by using PPGF yet without applying painting process, and the established method was applied to mass production while fulfilling the requirements for a good exterior appearance. In H&C molding, the metal molds are heated up by steam and cooled down by water after molding. This process works for making superior surface appearances and the appearance quality is determined by the temperature control of the molds. H&C molding has been generally applied to the parts with a flat shape and straight piping with a diameter of around 10 mm is arranged close to the surface of a metal mold cavity to get a good efficiency of temperature control. However, when this method is applied to a motorcycle part that is structured by three dimensional surfaces, these conventional piping arrangements cannot satisfy the requirements for a short molding cycle time and an even distribution of mold surface temperatures at the same time. In our study, a piping arrangement design by which the pipes are located along the three dimensional cavity surfaces was investigated. The piping arrangement design was determined based on the measurement results on test pieces and the molding cycle time of 100 seconds was eventually achieved. Furthermore, a proof testing to examine the material strength and the weather resistances is conducted as well.
Sugio, Daisuke, Okazaki, Shinpei, Kaneko, Mitsuo
Methods to Improve the Surface Quality of Microcellular Injection Molded Parts - A Review2016-36-022410/25/2016
The microcellular foam injection molding process is being widely applied by the thermoplastics industry. This process consists in a melted polymer injection mixed with a processing solvent, that is an inert gas in the supercritical state, usually CO2 or N2 producing a microcellular foam. This technique offers many advantages such as weight reduction, dimensional uniformization and less warpage. Besides that, it offers a satisfactory property like acoustic and thermal insulation. On the other hand, the parts from this process have an inferior mechanical property like ductility and toughness if compared with solid injection molded parts. Nevertheless, the main issue for this process is the poor appearance quality. This paper presents a review of some existing methods for surface quality improvement as Co-injection process, where a skin is injected over the microcellular part, and Heat & Cool that consists in a control of mold temperature. All the processes addressed were effective in the surface quality improvement. However, the produced parts through this method have a higher added value due some modifications done in the equipment.
Lima, Carla, Andrade, Filipe, Kawakami, Cristina, Gonçalves, Cristiane, Peraro, Walmir
Composite and Bonded Structure Engineers: Training DocumentAIR5278 (Current)10/13/2016
This document provides recommendations concerning the minimum knowledge and analytical skill guidelines for a composite and metal bond repair design engineer. Teaching levels have been assigned to this curriculum to define the knowledge, skills and abilities needed to design appropriate repairs. Minimum hours of instruction have been provided to ensure adequate lecture and laboratory coverage of all subject matter. These minimums may be exceeded, and may include an increase in the total number of training hours and/or increases in the teaching levels.
AMS CACRC Commercial Aircraft Composite Repair Committee
Laser Texturing Continues to Evolve in Medical ApplicationsTBMG-2561510/1/2016
In the medical device industry, surface texture has become an important aspect of product design. It not only provides the means to refine the physical appearance of an item, but also increases an item’s surface grip qualities. And through surface texturing, manufacturers can create medical tools that pick up less fluid and debris, mark implants for tracking, and add textures that aid in implant acceptance. So it is of no surprise that these medical manufacturers are increasingly seeking ways to improve the level of control exerted in surface texturing. Laser texturing is often the technology of choice and is now applied to many medical parts.
Fully Automated Series Production of 3D-Parts with the Composite Preforming Cell2016-01-21139/27/2016
Resin transfer molding (RTM) is gaining importance as a particularly economical manufacturing method for composites needed in the automotive and aerospace industries. With this method, the component is first shaped with dry fiber reinforcements in a so-called “preforming process” before the mold is placed in a RTM tool, injected with resin and cured. In recent years, Broetje-Automation has been developing innovative product solutions that are specially designed for these preforming processes and suitable for industrial use. For the first time ever, Broetje’s Composite Preforming Cell (CPC) makes large-quantity serial production of complex and near-net-shape preforms for composite components using this RTM process possible. With the additional integration of the patented 3D Composite Handling System Broetje impressively demonstrates its service and product portfolio in the area of innovative composite manufacturing technology and its know-how as a complete system integrator. This paper will focus on the innovative solution Composite Preforming Cell with integrated 3D Composite Handling System invented by Broetje-Automation.
Reinhold, Raphael
Processing and Manufacture of Inorganic-Organic Hybrid Syntactic Structural Cryogenic InsulatorTBMG-249687/1/2016
Reducing the cost and weight of launch structures is essential to meeting NASA goals for reliable access to space. Currently, separate systems are used for structure and pressure containment, cryogenic insulation, and high-temperature insulation. One way of reducing this cost and weight is through the development of multifunctional materials that can eliminate parasitic weight. Combining two functional components — structure and insulation — reduces weight and structural complexity, which usually is akin to fragility in the system, and minimizes the need for parasitic thermal protection and insulation systems.
Electroluminescent Skin for Healthcare RobotsTBMG-248036/1/2016
A team of Cornell University graduate engineering students say that they envision a future where a healthcare robot could display a patient’s temperature and pulse, and then read and react to a patient’s mood. Their research was published in the journal, Science.
Rings, Sealing, Phosphonitrilic Fluoroelastomer (Fz) Aviation Fuel ResistantAMS7284B (Current)5/3/2016
This specification and its associated detail specifications cover phosphonitrilic fluoroelastomers (FZ) in the form of molded rings.
AMS CE Elastomers Committee
Towards Integrative Simulation of Fatigue Loadings for Short Glass Fibers Reinforced Polyamide2016-01-03794/5/2016
Short glass fiber reinforced polyamides (SFRPs) are a choice material for automotive industry, especially for in the engine compartment. To develop their application field to more and more complex hydrothermal and mechanical environments, reliable or even predictive simulation technologies are necessary. Integrative simulation takes into account the forming process during final Finite Elements Analysis (FEA). For SFRPs, injection molding is taken into account by computing glass fibers orientation. It is further used to compute a specific anisotropic constitutive model on each integration point of FEA model. A wide variety of models is now available. Integrative simulation using Digimat has been proved very efficient for static and dynamic loadings. Its use for fatigue loadings is still under development in the frame of a consortium uniting Digimat Software editor, Solvay a major polyamide supplier, car makers (Toyota and PSA), tier one suppliers (TBVC and SOGEFI), and some European academic labs. Work led in the consortium has included upstream material studies aimed at SFRPS fatigue behavior modeling, algorithm development and CAE chain optimization. A big effort has also been made in order to model moisture sorption of polyamide parts in service conditions under the hood. The project has brought to correlations between parts tests and FEA case studies. Results obtained show satisfying correlations between actual behavior and predicted fatigue resistance. Work goes on to improve correlations and industrialize this new fatigue simulation technology.
Robert, Gilles, Moulinjeune, Olivier, Bidaine, Benoit
Fatigue Behavior of Neat and Short Glass Fiber Reinforced Polymers under Two-Step Loadings and Periodic Overloads2016-01-03734/5/2016
An experimental study was conducted to evaluate the variable amplitude fatigue behavior of a neat polymer (polypropylene impact co-polymer) and a polymer composite made of polybutylene terephthalate (PBT) with 30 wt% short glass fibers. Fatigue tests were conducted on un-notched and notched specimens at room temperatures. Plate-type specimens were prepared in the transverse direction with respect to the injection mold flow direction and a circular hole was drilled in the center of notched specimens. Two-step loadings (high-low and low-high) tests at two damage ratio of 0.2 and 0.5 at stress ratios of R = 0.1 and -1 were conducted to investigate load sequence effects and prediction accuracy of the linear damage rule. Different behaviors were observed for unreinforced and short glass fiber reinforced polymers under the two-step loading tests. Periodic overload tests were also conducted to evaluate the effect of overloads during cyclic loading on fatigue life and this effect was found to be less pronounced for polymeric materials, as compared to metallic materials.
Eftekhari, Mohammadreza, Fatemi, Ali, Khosrovaneh, Abolhassan
Type 12 10% Mineral, 2.5% Molybdenum Disulfide Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or ExtrusionsAMS3678/12A (Current)2/29/2016
This specification covers a polytetrafluoroethylene (PTFE) resin filled with 10% mineral and 2.5% molybdenum disulfide in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.
AMS P Polymeric Materials Committee
Type 16 15% Polyimide Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or ExtrusionsAMS3678/16A (Current)2/29/2016
This specification covers a polytetrafluoroethylene (PTFE) resin filled with 15% polyimide in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.
AMS P Polymeric Materials Committee
Type 15 15% Aromatic Polymer Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or ExtrusionsAMS3678/15A (Current)2/29/2016
This specification covers a polytetrafluoroethylene (PTFE) resin filled with 15% aromatic polymer in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.
AMS P Polymeric Materials Committee
Type 14 40% Bronze Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or ExtrusionsAMS3678/14A (Current)2/29/2016
This specification covers a polytetrafluoroethylene (PTFE) resin filled with 40% bronze powder in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.
AMS P Polymeric Materials Committee
Type 10 Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions with 15% Carbon FiberAMS3678/10B (Current)2/29/2016
This specification covers a polytetrafluoroethylene (PTFE) resin filled with carbon fiber in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.
AMS P Polymeric Materials Committee
Type 1 Virgin Polytetrafluoroethylene (PTFE) Moldings and ExtrusionsAMS3678/1C (Current)2/29/2016
This specification covers an unfilled grade of virgin polytetrafluoroethylene (PTFE) resin in the form of extruded or molded rods or tubes which are sintered after molding or, in the case of extrusions, sintered during the extrusion process.
AMS P Polymeric Materials Committee
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