Search Results

Spot Welds are a category of welds used extensively in automotive structures, normally for metals. The fatigue analysis of such spot welds can be evaluated using (a) the Point 2 Point (P2P) method where a beam or bar is used to connect the 2 surfaces being joined, (b) a more modern approach where the 1D element is replaced with an “equivalent” brick element, or (c) a third approach that falls somewhere between where a “spider” and circular ring of elements, is used to represent the spot weld. In all 3 cases there is an assumption that the cross section is circular. For some specialist cases such as plastic connectors, the cross section is not circular so a new user defined weld is proposed. This paper will describe the approach that is based on the concept that a user generated tensor line can be used (equivalent to the theoretical Force/Moment to stress algorithms built into the P2P approach) along with special S-N curves create for different joint shapes.

Often electrical components are encapsulated in a plastic material after assembly. The goal of this study is to determine what variables are most important in reducing potting variation and identify the key machine parameters which can be used to make adjustments to the potting process. To maximize the efficiency of testing, an L18 orthogonal array was used to structure an experiment. Hose temperature, orifice size, and pressure were found to be the most significant control factors studied in this experiment. Shifting from the initial settings for these factors to the recommended settings should increase the S/N of the potting process by 14.53db. Motor speed was found to be the most significant variable for adjusting the mean of the process. The noise factors induced in this study were found to be a significant source of variation. Filters can shift the mean potting material applied by 25% over their planned usage life. Moreover, new filters induce more variation than old filters.

Western Canada has large acreage of oilseed flax, but unfortunately a small percentage of total crop residue (flax straw) produced annually is being commercially used. Therefore, farmers are still burning the flax straw. Flax fiber and straw has highest strength amongst the different natural fibers, therefore, the prospect of using them as biorenewable reinforcement in recycled/ virgin polymer matrices has gained attention in recent years. Flax strawboard has a potential to replace the currently used wood and other crop like wheat/barley straw boards for different industrial application. In this research Oilseed flax straw reinforced composite boards were developed using flax shives with biopolymer binder made out of recycled/ pure thermo plastic and flax fiber. Some advantages of such materials are high strength, low density, good insulation capacity against heat and moisture transfer, and biodegradability.

The fastener analysis for an airframe panels under random cyclic loading conditions were analyzed with various elaborate solutions. But here a simple technique is proposed to analyze the problem and prove the necessity for a design solution. It is shown that the misfit in the fastener system reduces the load capacity of the joint due to the lack of contact or reduced contact. This reduced contact also produces various stress concentration at the contact zones. In the cyclic loading environment this reduced load capacity and increased stress concentration produces elastic plastic deformation around the contact locations and at the same time a crack develops and propagates beyond the fastener system. This creates a load leak transparent to the fastener system. Thus the misfit fastener systems have a higher probability of aging than the fit fasteners. With the proof in hand various design patterns were proposed to improve the fatigue characters under varying types of loading conditions.

High axial loads applied on conical roller bearings can lock the wheel hub after the fastener assembling. This assembly can be made, nowadays, using a castle nut plus a cotter pin or by plastic deformation of the nut to prevent its release. This procedure involves many components for the assembling, restrict its reuse, add extra costs, and provide possible failures during the assembling line or during the future maintenance. This work proposes to demonstrate the development of an efficient and easy system to mount wheel hubs on lines and later to assure maintenance without jeopardizing the efficiency and the functionality of the tapered roller bearing.

Several new families of expanding mandrel type of temporary (slave) fastener are in production and/or undergoing qualification tests. These fasteners are characterized by a collapsible mandrel that expands when needed over a center spindle. These fasteners are blind (installed and removed from one side only), and they provide locating (dowel) capabilities. This paper illustrates how these new fasteners work and how they are designed. Results of some testing of nominal ¼″, flush head fasteners in carbon-fiber reinforced plastic are shown. Design criteria include the temporary fasteners clamping ability, acceptable contact stresses, cyclic fatigue life, and strength.

Advanced material modeling was conducted to describe the thermal-mechanical behavior of Boron Steel during hot stamping, a process in which blanks at 900 °C are formed and quenched between cold dies. Plastic deformation, thermal dilatation and phase transformation were incorporated in the constitutive model and a user-defined subroutine was developed to interface with LS-DYNA. Simulation was conducted on the hot stamping process of a door intrusion beam to gain insight into the physics of the process. Results showed significant influence of the thermal cycle on final product. It was also demonstrated that the program developed can be used as an early feasibility tool to determine baseline processing parameters and to detect potential defects in products without physical prototyping.

In Brazil the market for plastic parts molds, in last few years had become very competitive, with several Vehicle Operations and a big number of a different models, and with today total market volume it means low volumes productions for each model. This market demands for good toolshops and at the same time a big pressure to reduce investments, one of the most important. Plastic components usage in the car, is increasing overtime, with new applications for Exterior, interior and powertrain, requiring new technologies for Injection molding processing and making molds to be more complex. The development of plastic parts in Brazil has its own characteristics, strengths and weaknesses. In fact a big and heterogeneous market. This paper intends to present an analysis of development of plastic parts in Brazil, considering the development of mold tooling locally, focusing the automotive market.

The advantages of magnetic implant induction welding (Emabond™)1 technology for various thermoplastics were widely discussed since the mid-eighties in a series of technical articles and reports, and presented to the professional Societies (SAE, SPE, SME, etc). In 1998-2003, we reported to SAE International our technical achievements in optimizing the mechanical performance of welded nylon (6, 66, 6/66, 46, etc.) using frictional (linear and orbital vibration, ultrasonic), contact (hot plate), and non-contact (laser through-transmission) welding technologies. Our recent developments focused on optimization of mechanical performance of induction welded nylon 6, which has reached a new performance level through continuous improvement of magnetic implant induction welding technology, including properties of the formulated magnetic implant material, new equipment, SPC process control, optimized design of joints, etc.

Thermoplastics have been used increasingly for automobile components for both interior and under-the-hood applications. The plastic parts are made through various molding process such as compression molding, injection molding and blow molding. For parts with large or complicated geometry, small portions of the part may have to be molded first, then joined together using a welding process. The welded regions usually exhibit inhomogeneous and inferior mechanical performance compared to the bulk regions due to the differences in thermal history. The microstructures and mechanical properties of welded thermoplastics have been examined using hot-plate welded polyethylene. The specimens are prepared at various thermal conditions to simulate the real welding process. The thermal properties in welds are monitored using DSC (Differential Scanning Calorimetry) and the crystallinities are calculated.

This paper examines some processing and design factors which affect the impact performance of cast A356 aluminum wheels, as measured by SAE J175 (13° lateral impact test). Wheel impact performance is discussed with respect to two different failure criteria: (a) failure due to cracking in the hub or spokes, and (b) failure due to total loss of tire air pressure. The general influence of heat treatment on impact behavior is described, and then examined in light of a particular wheel example. Peak-aging heat treatments are compared with underaging treatments, in terms of the critical link between processing, material properties of strength and ductility, and their influence on wheel impact behavior. The effects of the rim flange geometry and other design features are then explored, and illustrated with examples.

To reduce the amount of fuel vapor created in the fuel tank, we developed a variable-capacity, plastic bladder fuel tank that is efficient, reliable, and provides permeation prevention performance. This bladder fuel tank changes in shape and total capacity in accordance with the volume of fuel it holds. Thus, in contrast to the conventional fuel tank, it can dramatically reduce the amount of fuel vapor that is ordinarily created in the fuel tank while the vehicle is being refueled, parked, or driven. The bladder fuel tank has been adopted in the Vapor Reducing Fuel Tank System of the North American model Prius, a vehicle that operates under the Toyota Hybrid System (THS), which complies with the SULEV exhaust emission requirement. This paper primarily gives an outline of the technology for manufacturing the bladder fuel tank.

The vast majority of products contain joints, therefore, joining technology is key to the strategic implementation of new materials. This paper considers three innovative solutions to industrial problems ClearWeld™ A recently developed technique for laser welding materials, creating a joint almost invisible to the human eye. AdhFAST™ This novel, three-in-one fastener, allows adhesive to be injected through the middle of the device whilst retaining the joint and controlling bondline thickness Vitresyn™ Transparent plastics such as polycarbonate and acrylic have the potential to replace glass in a number of applications, car headlamps and spectacle lenses for example. However, these plastics are relatively soft materials and need protection against abrasion and scuff damage. This recently developed system gives good protection at acceptable cost

The objective of the research presented in this paper was to assess the influence of stamping process on crash response of UltraLight Steel Auto Body (ULSAB) [1] vehicle. Considered forming effects included thickness variations and plastic strain hardening imparted in the part forming process. The as-formed thickness and plastic strain for front crash parts were used as input data for vehicle crash analysis. Differences in structural performance between crash models with and without forming data were analyzed in order to determine the effects and feasibility of integration of forming processes and crash models.

The drive to reduce weight, simplify assembly, and cut total system cost in today's vehicles is relentless. Replacing metal systems with thermoplastics has been of considerable interest in the engineering community. The current generations of engineering thermoplastic resins are enabling the use of plastic systems in demanding underhood applications. Technical data and discussion regarding the materials, design, molding, and assembly of lightweight composite throttle bodies will be presented in this paper. Comparisons with machined aluminum throttle housings are drawn to establish a baseline with the throttle body housing component that is most common in production today. Design flexibility and process simplification are some of the approaches highlighted. Much of the technical information provided in the paper applies to both cable driven mechanical throttle bodies as well as electronic throttle bodies under development.

As the global auto industry wrote the final chapter on its first century, we saw the average thickness of an automotive instrument panel drop from 3.0 mm-3.5 mm to 2.0 mm-2.3 mm, as found in the 1999 Volkswagen Jetta and Golf. By reducing the wall thickness of the instrument panel, Volkswagen started an industry trend: both OEMs and tiers are investigating technologies to produce parts that combine a lower cost-per-part via material optimization and cycle-time reduction with the superior performance of engineering thermoplastics. The goal is to produce parts that are positioned more competitively at every stage of the development cycle - from design, to manufacturing, to assembly, to “curb appeal” on the showroom floor. The key to this manufacturing and design “sweet spot” is a technology called thinwall - the molding of plastic parts from engineering thermoplastics with wall thicknesses thinner than conventional parts of similar geometry.

Light-duty pickup trucks have been and are an important growing segment of the US automotive market. Like all other vehicles on the road, they must also do their part to conserve fuel and weight reduction is a vital tool for achieving this goal. Tailgates currently installed on pickup trucks typically weigh over 30 lbs. and weight loss in these panels is very desirable. Recent demographic shifts in truck users has also lead to more interest in light-weighting of components like the tailgate for ergonomic reasons. Manufacturers have reached the limit for light-weighting tailgates using current materials and manufacturing processes. This new concept changes the paradigm. It uses a hybrid system of aluminum and plastic composite materials along with new manufacturing and assembly processes to achieve a significant weight reduction without compromising performance or other desired attributes. This paper describes the design and demonstrates its viability via analysis and test results.

In the Metalworking Industry the design and the control of the processes have been traditionally based on the experience and, sometimes, considered as an art. The application of numerical methods reduces the costs of the design and elaboration processes and contributes to the improvement of the product quality. In this work the authors present the simulation of the cold compaction of a two-level powder metallurgical part using a commercial FEM code. The plastic behaviour has been represented by means of the Drucker-Prager/CAP model.

Carbon fiber composite use in automobiles and light trucks could dramatically reduce energy use and engine-out emissions. However, worldwide capacity of 28,000 tonnes per year of carbon fiber from polyacrylonitrile (PAN) and petroleum pitch could support limited automotive use. Production of high-volume, industrial-grade fiber from renewable and recycled polymers (lignin, recycled plastics, regenerated cellulosics) could meet automotive demand. Profiles of material volumes, carbon content, and melting points indicate several attractive candidates for production melt-spun carbon fiber feedstocks. Effects on the carbon fiber production cycle and its integration into automotive production are discussed.