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Sintered parts mechanical properties are very sensitive to final density, which inevitable cause an enormous density gradient in the green part coming from the compaction process strategy. The current experimental method to assess green density occurs mainly in set up by cutting the green parts in pieces and measuring its average density in a balance using Archimedes principle. Simulation is the more accurate method to verify gradient density and the main benefit would be the correlation with the critical region in terms of stresses obtained by FEA and try to pursue the optimization process. This paper shows a case study of a part that had your fatigue limit improved 1000% using compaction process simulation for better optimization.

Manual transmissions for passenger cars are facing pressures due to rapid growth of automatic transmissions, which already represents more than 60% of Brazil market, and from higher torque demand due to strict emission legislation, which turbo engines had presented great contribution to it. To solve this contradictory issue, gears with higher strength and lower cost have been studied to replacement Nickel by Niobium in the steels. Furthermore, this technology could be applied to solve the issues with electrified vehicle, where high torque, speed and lifetime are demanded pursued for gears. This study aimed to build prototypes and compare the S-N curves, fracture analysis, microstructure for three kinds of steels (QS4321 with Ni, QS1916 FG without Ni & with Nb and QS 1916 without Ni and Nb) in the condition carburized, hardened and tempered with and without shot peening.

Currently, the dominant technology used in the manufacture of mass-market automobile structures is sheet-metal stamping because of its suitability for producing accurate, strong, durable components in large quantities [1]. While cost-effective and fast for high-volume applications, the cost of manufacturing stamping dies is difficult to profitably amortize over a low-volume product in any but the most high-priced vehicle segments. This study examines the application of automated fabrication technologies as an alternative to stamping for the production of low-volume body structure components, including the impacts on both design and performance.

Structures with multiple materials have now become one of the perceived necessities for automotive industry to address vehicle design requirements such as light-weight, safety, and cost. The objective of this study is to develop a design methodology for multi-material structures accountable for vehicle crash durability. The heuristic topology synthesis approach of Hybrid Cellular Automaton (HCA) framework is implemented to generate multi-material structures with the constraint on the volume fraction of the final design. The HCA framework is integrated with ordered-SIMP (solid isotropic material with penalization) interpolation, artificial material library, as well as statistical analysis of material distribution data to ensure a smooth transition between multiple practical materials during the topology synthesis.

Fatigue is one of the most common failure mechanism in engineering structures. The statistical nature of fatigue life and the stress gradient are the two challenges among many while designing any component or structure for fatigue. Fatigue lives of the identical components exhibit the considerable variation under the same loading and operating conditions due to the difference in the material micro-structures and other uncontrolled parameters. Stress concentration at the notch causes stress gradient and therefore, applying the plane specimen results for actual engineering components with notches does not give quantitatively reliable results if the stress gradient effects are not considered. The objective of the work presented here was to carry out the fatigue tests of un-notched, U and V-notch specimens which were die cast using aluminum alloy (A380) and to obtain fatigue life using a variable critical distance method which considers the stress gradient due to the notch geometry.

Simple planetary gears are widely used in automobile industry due to their compact design and high power density. A simple planetary gear set consists of a Sun gear, Ring gear, Planets and Carrier which houses planet gears. Mounting of planet pinions on carrier is through pins which is supported on needle roller bearings. A process called staking is used to assemble the pinion pins on to the carrier. Pinion pins have a staking region which after assembly expands outward into staking groove on the carrier to prevent axial movement of the pins. Design of the groove plays a vital role for the fixation of planet pins and robustness a carrier. Planetary carrier staking grooves are designed to meet pinion pin retention and strength targets.

Among the most important finishing structures of a vehicle interior, the door trim panels reduce external noises, present ergonomic concepts generating comfort, improve appearance, and provide objects storage, knobs and buttons. The panels usually composed of several molded parts (trim, armrest, etc.) connected to each other also have structural function as support closing loads, protect occupants of door internal mechanisms, energy absorption in side impacts and resist misuse conditions. Therefore, these trims usually made of polymeric materials must to present good structural integrity, demanding appropriate connections between components to have good load distribution. The connections between parts can be made using bolts, interference fits (like self-locking), welding tubular plastic towers (heat stakes), or clips (such as snap fits) and last two are the most common due to be cheap and with good retention.

The Austempering heat treatment is a well-known solution to improve the mechanical properties of ductile cast irons, therefore being referred as 'ADI' (Austempered Ductile Iron). The improved mechanical properties of ADI's with respect to conventional ductile iron is attributed to its resulting microstructure, which contains mainly carbide-free bainite with stabilized retained austenite. More recently, ductile cast irons were submitted to another heat treatment, known as 'Quenching and Partitioning' (Q&P). In this case, the ductile cast iron is austenitized, quenched to a temperature between Mf and Ms temperatures and subsequently heated to a temperature above Ms in order to partition the carbon from the martensite to the remaining austenite. The resulting microstructure comprises mainly low carbon martensite, austenite (stabilized by the carbon partition) and carbide-free bainite. Such microstructure resulted in equal or better properties than ADI.

The present work aims to characterize the microstructure of valvetrain camshaft lobes that are currently applied in the automotive industry, obtained by different processing routes. The cam lobe microstructure has been assessed by microscopy, whereas the mechanical properties by hardness profile measurements on the surface region. Microconstituents type and form, composing the final microstructure at the cam lobe work region, are defined by the casting route and/or post-heat treatment process other than alloy chemical composition, so that knowledge and control of processing route is vital to assure suitable valvetrain system assembly performance and durability. Most of the mechanical solicitations on the part occur at the interface between cam and follower; the actual contact area is significantly smaller than the apparent area. As a result, the microstructure at and near the surface performs a direct role on the performance of the valvetrain, cam lobe and its counterpart.

The so-called Modified Martempering discussed in this work differs from the standard martempering by that the temperature of the quenching bath is below the Ms point. In spite of the fact the lower temperature increases the severity of quenching, this also usually avoids the bainite formation, and by this reason, it is possible to make a fair comparison between different processes, which result in different microstructures. The present study shows the results in terms of mechanical properties, impact resistance in special of a cold work tool steel class, after being heat treated by the isothermal modified martempering process, as well as a comparison with the conventional quenching and tempering process and the austempering as well.

Forming Limit Curves (FLCs) were developed for the 5083 aluminum alloy at conditions simulating high temperature processes such as superplastic and quick plastic forming. Sheet samples were formed at 450 °C and at a constant strain rate of 5x10-3 s-1, by free bulging into a set of elliptical die inserts with different aspect ratios. Friction-independent formability diagrams, which distinguish between the safe and unsafe deformation zones, were constructed. Although the formability diagrams were confined to the biaxial strain region (right side quadrant of an FLD), the elliptical die insert methodology provides formability maps under conditions where traditional mechanical stretching techniques are limited.

In order to reduce the number of head injuries sustained by pedestrian accidents, safety engineers are developing pedestrian friendly hood systems through gauge optimization of the hood inner panel. In this study, the clinch method was employed to assemble a pedestrian friendly hood with a 0.5mm thick inner panel. Static and dynamic analyses were carried out to determine the clinch experiencing the highest loads and to understand the fatigue behavior of a clinched hood during a slam event. The macroscopic failure modes of clinched joints by hood slam were studied by means of a scanning electron microscope. A simple equation was derived to correlate the hexahedron spot weld model as a substitute for clinching in order to obtain an equivalent stiffness for a clinched joint within the linear region of an F-D curve. The F-D curve was obtained by lap shear testing.

Quasi-static tensile properties of TRIP590 steels from three different manufacturers were investigated using digital image correlation (DIC). The focus was on the post-uniform elongation behavior which can be very different for steels of the same grade owing to different manufacturing processes. Miniature tensile specimens, cut at 0°, 45°, and 90° relative to the rolling direction, were strained to failure in an instrumented tensile stage. True stress-true strain curves were computed from digital strain gages superimposed on digital images captured from one gage section surface during tensile deformation. Microstructural phases in undeformed and fracture specimens were identified with optical microscopy using the color tint etching process. Fracture surface analyses conducted with scanning electron microscopy and energy dispersive spectroscopy were used to investigate microvoids and inclusions in all materials.

Efficient methods for simulating operators performing part handling tasks in manufacturing plants are needed. The simulation of part handling motions is an important step towards the implementation of virtual manufacturing for the purpose of improving worker productivity and reducing injuries in the workplace. However, industrial assembly tasks are often complex and involve multiple interactions between workers and their environment. The purpose of this paper is to present a series of industrial simulations using the Human Motion Simulation Framework developed at the University of Michigan. Three automotive assembly operations spanning scenarios, such as small and large parts, tool use, walking, re-grasping, reaching inside a vehicle, etc. were selected.

The need for fuel economy gains is crucial in todays automotive market. There is also growing interest and knowledge of greenhouse gases and their effect on the environment. Paulstra's magnesium powertrain brackets were a solution that was presented not just to reduce the weight of the engine mounting system (which was already under its weight target before magnesium introduction), but in response of the OEM's desire to further reduce the weight of the vehicle for CAFE and weight class impact. This new engine mounting system has three powertrain mount brackets that are high-pressure die cast AZ91D magnesium alloy. This paper will show that these brackets to have a dramatic weight reduction compared to the standard aluminum die-cast material that they replaced. This paper describes the process of approval: concept and material sign-off by the OEM, FEA for strength and modal performance, corrosion, and the final product.

This paper describes the design and development of the rear compartment structure of the sixth generation Corvette, C6, which starts in the 2005 model year. The improved design integrates the rear compartment packaging to address issues seen on fifth generation Corvette, C5. The molded composite fiberglass reinforced, tub and surround panels are similar to the C5. These large panels are modified to fit the new styling theme of the C6, while also addressing the packaging requirements of the updated underbody structure and exhaust system. New composite side support brackets and cross car reinforcement combine to address several desired improvements. These side support brackets are designed to package the rear audio speakers, electrical modules, wiring and cable routing while also addressing build variation and localized stiffness improvement. The side brackets support the surround panel increasing the manufacturing control of the surround panel.

Ten mold-in-color black polymers were evaluated for exterior weathering in an attempt to improve the specifications for exterior mold-in-color plastics to meet five year durability for a 95th percentile sunbelt customer. Four different weathering methods were utilized including Arizona exposure, Florida exposure, and Xenon arc exposures per the GMNA and the GM Europe methods. Colorfastness, gloss retention and other material property changes due to weathering were measured and analyzed against two GM durability standards. For the appearance attributes, correlations between actual exposure and accelerated exposure were attempted. Test results before and after polishing were also analyzed. Finally, in addition to comparing the performance of the ten polymers, the four weathering methods are compared and discussed with recommendations for the preferred testing regimen.

This paper presents a simplified approach for formability simulation of automotive body structural sections in the early design stage of vehicle development process. Plane strain approach is investigated for its applicability and accuracy by comparing the analytical results with the measured results of automotive body side panel. The plane strain approach was tried based on the fact that for a certain section location of a stamped panel, the minor strains are relatively small and negligible compared to the major strains. The state of plane strain can be induced mainly through symmetry and applied boundary conditions. This approach is both cost effective and time saving for analyzing sheet metal formability in early vehicle development stage, since only few sections of the entire panel need be analyzed.

The main objective of this paper is to simulate the springback using combined kinematic/isotropic hardening model. Material parameters in the hardening model are identified by an inverse method. Three-point bending test is conducted on 6022-T4 aluminum sheet. Punch stroke, punch load, bending strain and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Material parameters are identified by minimizing the normalized error between two bending moments. Micro genetic algorithm is used in the optimization procedure. Stress-strain curves is generated with the material parameters found in this way, which can be used with other plastic models. ABAQUS/Standard 5.8, which has the combined isotropic/kinematic hardening model, is used to simulate draw-bend of 6022-T4 series aluminum sheet. Absolute springback angles are predicted very accurately.

In June 1997, the Vehicle Recycling Partnership (VRP) and the American Plastics Council (APC) asked MBA Polymers to conduct a study to determine the technical and economic feasibility of recovering metals and plastics from end-of-life radiator end caps (RECs). The VRP worked with the Institute of Scrap Recycling Industries (ISRI) to obtain samples of RECs from two metal recycling companies, SimsMetal America and Aaron Metals. MBA performed its standard Recyclability Assessment on the materials, which included a detailed density and material characterization study and an actual processing study using its pilot processing line. It was found that the polyamide from RECs could be recovered in reasonably high yield and purity using tight density separations. The recycling of the REC samples used for this study generated about 40% nonferrous metal, 19% mixed ferrous and nonferrous metal and about 20% polyamide flakes.