Browse Topic: Extrusion

Items (753)
This specification covers established manufacturing tolerances applicable to titanium and titanium alloy extruded bars, rods, and shapes. These tolerances apply to all conditions, unless otherwise noted. The term "excl" applies only to the higher figure of the specified range.
AMS G Titanium and Refractory Metals Committee
AMS4325A prohibits unauthorized exceptions (3.7), revises condition (3.2), properties (3.4.5), quality (3.5.1), reports (4.4.1), and identification (5.1.1), and results from a Five-Year Review and update of this specification.
AMS D Nonferrous Alloys Committee
This specification covers an aluminum alloy in the form of extruded bars, rods, wire, profiles, and tubing.
AMS D Nonferrous Alloys Committee
This specification covers an aluminum alloy in the form of extruded bars, rods, wire, profiles, and tubing up to 32 square inches (206 cm2) in area (see 8.5).
AMS D Nonferrous Alloys Committee
Experimental Investigation of Axial Cutting of AA6061 Extrusions under a Tension Deformation Mode2020-01-02064/14/2020
A plethora of applications in the transportation industry for both vehicular and roadside safety hardware, especially seatbelts, harnesses and restraints, rely on tensile loading to dissipate energy and minimize injury. There are disadvantages to the current state-of-the-art for these tensile energy absorbers, including erratic force-displacement responses and low tensile force efficiencies (TFE). Axial cutting was extensively demonstrated by researchers at the University of Windsor to maintain a stable reaction force, although exclusively under compressive loading. A novel apparatus was investigated in this study which utilized axial cutting under a tensile loading condition to absorb energy. A parametric scope was chosen to include circular AA6061 extrusions in both T4 and T6 temper conditions with an outer diameter of 63.5 mm and wall thickness of 3.18 mm. The experiments were performed quasi-statically utilizing a custom, hydraulically powered long stroke tension/compression testing machine with a maximum capacity of 300kN. Strain-gauge based load cells and non-contact displacement transducers were implemented to measure the cutting force and displacement response of the setup. The results demonstrated highly stable force responses, with cutting force efficiencies typically in the vicinity of 90%. The experimental force-displacement responses exhibited a high degree of repeatability and correlation to the analytical model. Critical performance metrics, including the mean load and total energy absorption, were predicted to within 5 %. Additionally, the complete force-displacement response was predicted utilizing an analytical modeling approach with an average validation metric of approximately 0.92.
Gudisey, AnthonyAltenhof, WilliamMagliaro, John
Lattice Boltzmann Simulations of Flow Over an Iced Airfoil2019-01-19456/10/2019
This paper presents an aerodynamic degradation study of an iced airfoil, using the Lattice Boltzmann approach with the commercial software PowerFLOW. Three-dimensional numerical simulations were performed with an extruded constant section of the GLC-305 airfoil with a leading-edge double-horn ice shape using periodic boundary conditions. The freestream Reynolds number, based on the chord, is 3.5 million and the Mach number is 0.12. An extensive comparison of the main flow features with experimental data is performed, including aerodynamic coefficients, pressure coefficient distributions, velocity and turbulence contours along with its profiles at several positions, and stagnation streamlines. The drag coefficient agrees well with experiments, in spite of a small shift. Two different wind tunnel measurements, using different measurement techniques, were compared to the CFD results, which mostly stayed in between the experimental data. Velocity and turbulence intensity contours as well as stagnation streamlines enabled a more detailed comparison of the flow field, which showed great accuracy of the simulations to predict the reattachment location. Overall, very good agreement is obtained with the available reference data. The numerical tool used to calculate the aerodynamic performance was able to deal with very complex flows, which in this case is highly unsteady, turbulent and characterized by large recirculation zones downstream of the ice. Such flow unsteadiness is caused by the flow separation and adverse pressure gradients. A mesh resolution analysis indicated grid convergence using a medium resolution setup, which provided good accuracy with fast turnaround times for the simulations. This enabled a complete angle of attack polar sweep, including post-stall angles.
Ihi, RafaelRibeiro, AndreSantos, LuisSilva, Daniel
A Comparison of the Mechanical Performance of AA6061-T6 Extrusions Subjected to Axial Crushing and Axial Cutting2019-01-10944/2/2019
Conventional axially loaded energy absorbers dissipate kinetic energy through progressive folding. The significant fluctuations in load and high risk of transition to global bending are drawbacks that engineers have attempted to mitigate through several methods. A novel energy dissipation mechanism, referred to as axial cutting, utilizes thin-walled extrusions and a strengthened cutting tool to absorb energy in an axial impact. Compared to progressive folding, this can be achieved with minimal fluctuations in load during the deformation process. Based upon estimates from finite element models, a series of test cases were postulated where, for 8 and 10-bladed cutting scenarios, greater total energy absorption could be achieved through axial cutting than with progressive folding of geometrically similar extrusions. The specimens were AA6061 extrusions having T6 temper conditions that possessed 63.5 mm outer diameters and 1.5 mm wall thicknesses. All tests were performed quasi-statically using a universal MTS testing machine at a crushing rate of 50 mm/min. The axially cut extrusions displayed an average of 22.8 % more energy absorption than their respective axially crushed test specimens with an improved crush force efficiency, greater by a factor of 2. Finite element models utilizing an Arbitrary Lagrangian-Eulerian mesh were developed and solved with LS-DYNA R8.0.0 to numerically replicate the load-displacement responses of the axially cut extrusions. The steady-state cutting force was typically predicted to within 10% of experimental values with corresponding validation metrics generally above 0.90.
Magliaro, John A.Altenhof, William
Estimation of Cutting Parameters in Two-Stage Piercing to Reduce Edge Strain Hardening2019-01-10924/2/2019
Edge fracture is a common problem when forming advanced high strength steels (AHSS). A particular case of edge fracture occurs during a collar forming/hole extrusion process, which is widely used in the sheet metal forming industry. This study attempts to relate the edge stretchability in collar forming to the strain hardening along the pierced edge; thus, Finite Element (FE) simulations can be used to reduce the number of experiments required to improve cutting settings for a given material and thickness. Using a complex-phase steel, CP-W 800 with thickness of 4.0 mm, a single-stage piercing operation is compared with a two-stage piercing operation, so called shaving, in terms of strains along the pierced edge, calculated by FE simulation. Results indicated that strains were reduced along the pierced edge by shaving. These results are correlated with experimental observations made at the Technical University of Munich (TUM) where better hole expansion ratios (HERs) were obtained using shaving as opposed to single-stage piercing. Moreover, in this study, the combination of cutting parameters that would generate the least edge strain hardening is evaluated based on simulation results. This approach could reduce the need for hardness measurements along the pierced edge as well as the number of experiments required to improve the shaving process.
Diaz-Infante, DavidNarayanan, AdvaithAltan, Taylan
Dimensional Variation in Long Runout Length Direct Extruded 6000 Series Aluminum Alloy2018-01-01044/3/2018
In a drive to reduce overall vehicle weight, automotive manufacturers continue to look to aluminum alloys as a solution to provide complex lightweight structures. Precipitation hardened 6000 series aluminum alloys offer a mature commercially viable solution which may be produced using several different forming methods including the extrusion process. In some cases, aluminum products may be produced at a temper suitable for forming and later precipitation hardened to a temper with mechanical properties that meet structural requirements. Direct extrusion press capabilities continue to expand. In an effort to improve productivity, the runout lengths for presses have increased in an effort to reduce dead cycle time inherent to billet heating and loading. Long runouts, however, result in larger differences in pressure applied during extrusion. This pressure variation, confounded with differences in quenching and stretching, causes variation in the extruded product. The purpose of this study is to report the results of a variation study of extruded product before and after stretching. Results are correlated to position in the extrude length and thermal history related to quench. The post extrusion stretch-to-straighten operation yields different results based on the length of time in quench. This observation led to a more in-depth analysis of % stretch. Results of dimensional variation as function of % stretch are reported with a proposed optimum % stretch to reduce dimensional variation. These results are mapped to the quench duration and delay in the long length runout. Preliminary data is also provided comparing extrusions with different geometries as well.
Vinarcik, Edward JohnTalbert, Gregory
Fracture Characteristic Prediction of High-Strength Aluminum Alloy Extrusion using Cockcroft-Latham Ductile Fracture Criteria2018-01-01094/3/2018
Demands are increasing for the reduction of vehicle weight to enhance automobile fuel efficiency and driving performance, with the use of aluminum alloys expected to help. High-strength aluminum alloys (6xxx series, 7xxx series) are called for to enhance crash safety performance, and the prediction of material fracture is a key factor in the application of these alloys. This research presents a FEM model that can predict both tensile fracture and bending fracture when large deformations occur in the extrusion direction of high-strength aluminum alloy extrusion. The fracture characteristics of high-strength aluminum alloy extrusion were obtained by tensile and bending tests, and the factors governing ductile performance were clarified. Fracture was defined in the FEM model using the Cockcroft-Latham ductile fracture model. In addition, the surface crystal grain of aluminum extrusion becomes coarse as a result of the extrusion process, and the hardness distribution also exhibits a soft surface layer. Therefore, a definition that varies the material properties in the plate thickness direction, using the definition of laminate material as the composite material, was added to the FEM modeling process. FEM structural analysis was performed with tensile and bending tests using these definitions, and the analysis accuracy was verified. The results showed that the FEM structural analysis of tensile and bending tests reproduced the experimental results for load and stroke fractures to within an error of 10%. In order to describe tensile fracture and bending fracture in the direction of high-strength aluminum alloy extrusion using FEM, the Cockcroft-Latham ductile fracture model was combined with a method of varying the material properties in the plate thickness direction, according to the definition of laminate material. This enabled an accurate fracture load and stroke prediction within an error of 10%.
Sugimoto, NaoTakaki, NaokiTakada, Kenji
Meshing Considerations for Automotive Shape Design Optimization2016-01-13894/5/2016
High quality mesh generation technology coupled with a robust shape deformation technique enables large design space exploration for optimization without the need to remesh the geometry. To demonstrate this, we present a collection of best practices for cleaning complex analytic CAD data that together with a robust grid generation algorithm enable the automatic generation of high quality boundary layer resolved grids that retain their quality when morphed during the optimization process. The case study for this work is the DrivAer model developed by the Institute of Aerodynamics and Fluid Mechanics at the Technische Universität München. The first step in the proposed automated optimization framework is to use a technique called Solid Meshing to heal faults in the provided geometry and recover its original engineering intent. The aforementioned technique coupled with Pointwise’s anisotropic tetrahedral extrusion algorithm (T-Rex), enables automated, high quality volumetric grid generation. A technology called Arbitrary Shape Deformation (ASD) is then used to smoothly morph the DrivAer volume grid using a small set of shape change parameters. The robustness of this morphing technology enables the achievement of large grid deformations while maintaining cell quality and surface boundary layer thickness and orientation. As mentioned, the proposed design optimization framework eliminates the need to regenerate the grid after every volumetric deformation. This, in turn, minimizes the effect of changes to the characteristics of the grid on the simulation results.
Carrigan, TravisLandon, MarkPita, Claudio
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