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An experimental investigation was conducted to evaluate tensile and fatigue behaviors of two thermoplastics, a neat impact polypropylene and a mineral and elastomer reinforced polyolefin. Tensile tests were performed at various strain rates at room, −40°C, and 85°C temperatures with specimens cut parallel and perpendicular to the mold flow direction. Tensile properties were determined from these tests and mathematical relations were developed to represent tensile properties as a function of strain rate and temperature. For fatigue behavior, the effects considered include mold flow direction, mean stress, and temperature. Tension-compression as well as tension-tension load-controlled fatigue tests were performed at room temperature, −40°C and 85°C. The effect of mean stress was modeled using the Walker mean stress model and a simple model with a mean stress sensitivity factor.

A hot and cold water mixing process with a steam condenser and a chilled water heat exchanger is set up for an engine EGR fouling test. The test rig has water recycled in the loop of a pump, heat exchangers, a three-way mixing valve, and a test EGR unit. The target unit temperature is controlled by a heating, cooling and mixing process with individual valves regulating the flow-rate of saturated steam, chilled water and mixing ratio. The challenges in control design are the dead-time, interaction, nonlinearity and multivariable characteristics of heat exchangers, plus the flow recycle in the system. A systems method is applied to extract a simple linear model for control design. The method avoids the nonlinearity and interaction among different temperatures at inlet, outlet and flow-rate. The test data proves the effectiveness of systems analysis and modeling methodology. As a result, the first-order linear model facilitates the controller design.

This paper presents a technological comparison of weldability and mechanical properties between a dual phase steel (DP) and an advanced high strength low alloy steel (AHSLA) used for automotive structural parts in order to demonstrate some unclear characteristics of each. Samples were spot welded and had their hardness and microstructure analyzed, also a shear test was applied on the weld button area. The edge stretchability was analyzed using hole expansion tests and tensile tests to determine the tensile and yield strength, anisotropic coefficients and total elongation. Data were used to estimate crash energy absorption. The results showed an AHSLA steel with higher than typical ductility. Finally, while DP showed improved stretchability, it was also concluded that such AHSLA could perform better bendability, drawability, flangeability and weldability.

A methodology that enables two-dimensional strain field measurement in the vicinity of ductile rupture is described. Fully martensitic steel coupons were strained to fracture using a miniature tensile stage with custom data and image acquisition systems. Rupture initiated near the center of each coupon and progressed slowly toward the gage section edges. A state-of-the-art digital image correlation technique was used to compute the true strain field before rupture initiation and ahead of the resulting propagating macroscopic crack before final fracture occurred. True strains of the order of 95% were measured ahead of the crack at later stages of deformation.

Magnesium alloys are not corrosion resistant in many applications and they require coating protection. In this study, we developed an electroless E-coating technique for magnesium alloys and discussed a cathodic E-coating deposition mechanism for the electroless E-coating process. This coating can be formed within a few seconds by dipping a magnesium alloy (i.e., AZ91D) in an E-coat bath without applying a current or voltage. The deposited electroless coat can offer good protection to the AZ91D magnesium alloy in 5 wt% NaCl corrosive solution as well as in a phosphating bath. The most interesting finding is that the electroless coating is not sensitive to local damage. No preferential corrosion attack occurred along the scratches made on the coating.

New seal cross-section development is a very tedious and time consuming process if conventional analysis methods are used, as it is very difficult to predict the dimensions of the seal that will satisfy the sealing performance targets. In this study, a generic cross-section is defined and the design constraints are specified. Isight then runs the FEA model, utilizing a custom python script for post-processing. Isight then updates the dimensions of the seal and continues running analyses. Isight was run using two different design exploration techniques. The first was a design of experiments (DOE) to discover how the seal’s response varies with its dimensions. Then, after the analyst examined the results, Isight was run in optimization mode focusing on feasible design areas as determined from the DOE. Thus, after the initial model setup, the user can run the analyses in the background and only needs to interact with the program after Isight has determined a list of feasible designs.

Heat treated cast aluminum components like engine blocks and cylinder heads can develop significant amount of residual stress and distortion particularly with water quench. To incorporate the influence of residual stress and distortion in cast aluminum product design, a rapid simulation approach has been developed based on artificial neural network and component geometry characteristics. Multilayer feed-forward artificial neural network (ANN) models were trained and verified using FEA residual stress and distortion predictions together with part geometry information such as curvature, maximum dihedral angle, topologic features including node's neighbors, as well as quench parameters like quench temperature and quench media.

Laser welding of dissimilar metals such as Aluminum and Copper, which is required for Li-ion battery joining, is challenging due to the inevitable formation of the brittle and high electrical-resistant intermetallic compounds. Recent research has shown that by using a novel technology, called laser braze-welding, the Al-Cu intermetallics can be minimized to achieve superior mechanical and electrical joint performance. This paper investigates the robustness of the laser braze-welding process. Three product and process categories, i.e. choice of materials, joint configurations, and process conditions, are studied. It is found that in-process effects such as sample cleanness and shielding gas fluctuations have a minor influence on the process robustness. Furthermore, many pre-process effects, e.g. design changes such as multiple layers or anodized base material can be successfully welded by process adaption.

Vehicle sound insulation systems, such as front of dash mats or carpet assemblies, etc. play a key role in controlling vehicle interior noise. However, dash and carpet insulators are often designed to have varied thickness in compliance with packaging constraints or to fulfill manufacturing clearance requirements. While it is obvious to NVH engineers that thinned-down areas would significantly affect the insulation performance, design engineers would benefit from a quick tool to flag any design details that may negatively impact the performance. This paper therefore proposes a concept called the performance equivalent thickness for the sound insulation system. The aim is to link acoustic performance of an insulator layer to a geometric measure so that the component performance can be easily monitored and preserved at the design stage.

Global regulations intended to enhance pedestrian protection in a vehicle collision, thereby reducing the severity of pedestrian injuries, are presenting significant challenges to vehicle designers. Vehicle hoods, for example, must absorb a significant amount of energy over a small area while precluding impact with a hard engine compartment component. In this paper, a simple passive approach for pedestrian protection is introduced in which thin metal alloy sheets are bent to follow a C-shaped cross-sectional profile thereby giving them energy absorbing capacity during impact when affixed to the underside of a hood. Materials considered were aluminum (6111-T4, 5182-O) and magnesium (AZ31-O, AZ61-O, ZEK100) alloys. To evaluate the material effect on the head injury criterion (HIC) score without a hood, each C-channel absorber was crushed in a drop tower test using a small dart.

Edge fracture is one of the major issues for stamping Advanced High Strength Steel (AHSS). Recent studies have showed this type of fracture is greatly affected by an improper trimming process. The current production trimming process used for the conventional mild steels has not been modified for AHSS trimming. In addition to the high-energy requirement, the current mechanical trimming process would generate a rough edge (burr) with microcracks in trimmed edges for AHSS trimming, which could serve as the crack initiation during forming. The purpose of this study is to develop a proper production trimming process for AHSS and elucidate the effect of the trimmed edge conditions on edge fracture. A straight edge shearing device with the capability of adjusting the shearing variables is used in this study.

This work analyzes the lubricant supply to critical regions of needle roller bearing of an automatic transmission. The needle roller bearing is a critical component of an automatic transmission and it has several rotating cylindrical needle rollers that are having relative motion with inner surface of the pinion. Supply of lubricant to the needle roller bearings is very essential to prevent failure of the bearings due to frictional contact between rollers and inner surface of pinion. The supply of lubricant to the needle roller bearings depends on the location of oil supply hole. Lubricant supply to the needle roller bearings of an automatic transmission is studied using commercial 3D Computational Fluid Dynamics (CFD) software for different oil supply positions. CFD simulation is performed for the region between the pinion supply hole and end of the needle bearings including all needles. Lubricant is supplied to the needle bearing from the pinion pin oil supply hole.

Variable displacement vane pumps are becoming more popular for engine oil circuits due to their fuel savings over traditional fixed displacement pumps. As a result, engineers need to analyze these pumps to ensure the pump design meets the demands of the oil circuit while having good friction characteristics and avoiding issues like high pressure amplitude and resonance. By employing 1D flow simulation to these pumps, the user can analyze the most important issues surrounding vane pumps at a fraction of the time as 3D CFD. This paper showcases the prediction of several major performance quantities of a variable displacement vane pump including flow rate, pressure rise, and friction torque vs. engine speed and temperature. The simulation results show good correlation to measurement data. In addition, the pressure pulsation at several locations including in the vane chamber and at the outlet is compared directly with 3D CFD for a different pump.

SAE J2562 defines the background, apparatus and the directions for modifying the Scaled Base Load Sequence for a given a wheel rated load for a wheel design. This practice has been conducted on multiple wheel designs and over one hundred wheel specimens. All of the wheels were tested to fracture. Concurrently, some of the wheel designs were found to be unserviceable in prior or subsequent proving grounds on-vehicle testing. The remainder of the wheel designs have sufficient fatigue strength to sustain the intended service for the life of the vehicle. This is termed serviceable. Using the empirical data with industry accepted statistics a minimum requirement can be projected, below which a wheel design will likely have samples unserviceable in its intended service. The projections of serviceability result in a recommendation of a minimum cycle requirement for SAE J2562 Ballasted Passenger Vehicle Load Sequence.

An aspect of high performance brake design that has remained strikingly empirical is that of determining the correct sizing of the brake pad - in terms of both area and volume - to match well with a high performance vehicle application. Too small of a pad risks issues with fade and wear life on the track, and too large has significant penalties in cost, mass, and packaging space of the caliper, along with difficulties in maintaining adequate caliper stiffness and its impact on pedal feel and response time. As most who have spent time around high performance brakes can attest to, there methods for determining minimum brake pad area, usually related in some form or another to the peak power the brake must absorb (functions of vehicle mass and top speed are common). However, the basis for these metrics are often lost (or closely guarded), and provide very little guidance for the effects of the final design (pad area) deviating from the recommended value.

Automotive manufacturers are facing continuously changing Global environment. Traditionally, these manufacturers relied on structural and general durability tests to validate vehicles. For these tests to remain representative of customer usage in a Global environment, the overall surface conditions of the Global road systems must be studied. Understanding and classifying these road systems conditions is an important step in dealing with vehicle durability in the Global environment. In this paper, an approach to mapping the world road systems into Established Roads (ER) and Developing Roads (DR), utilizing Statistical Discriminant Analysis (SDA), is presented. The classification of Global regions as DR and ER road systems can be effectively used to recommend appropriate development and validation tests for each road system. A few examples are presented to demonstrate how the ER vs.

Wire shorts on an in-vehicle controller area network (CAN) impact the communication between electrical control units (ECUs), and negatively affects the vehicle control. The fault, especially the intermittent fault, is difficult to locate. In this paper, an equivalent circuit model for in-vehicle CAN bus is developed under the wire short fault scenario. The bus resistance is estimated and a resistance-distance mapping approach is proposed to locate the fault. The proposed approach is implemented in an Arduino-based embedded system and validated on a vehicle frame. The experimental results are promising. The approach presented in this paper may reduce trouble shooting time for CAN wire short faults and may enable early detection before the customer is inconvenienced.

In the vehicle development process, one important step is to set a component performance target from the vehicle level performance. Conventional barrier-decoupler dash mats and floor trim underlayment systems typically provide sound transmission loss (STL) with minimal absorption. Thus the performance of such components can be relatively easily specified as either STL or Insertion Loss. Lightweight dissipative or multi-layered acoustic materials provide both STL and significant absorption. The net performance is a combination of two parameters instead of one. The target for such components needs to account for this combined effect, however different suppliers use unique formulations and manufacturing methods, so it is difficult and time consuming to judge one formulation against another. In this paper, a unique process is presented to set a component target as a combined effect of STL and absorption.

More Mg alloys are being considered for uses in the automotive industry. Since the corrosion performance of Mg alloy components in practical service environments is unknown, long term corrosion testing at automotive proving grounds will be an essential step before Mg alloy components can be implemented in vehicles. However, testing so many Mg alloy candidates for various parts is labor intensive for the corrosion engineers at the proving grounds. This report presents preliminary results in evaluating corrosion performance of Mg alloys based on rapid corrosion and electrochemical tests in the lab. In this study, four Mg alloy candidates for transmission cases and oil pans: AE44, AXJ530, MRI153M and MRI230D were tested in the lab and at General Motors Corporation Milford Proving Ground and their corrosion results were compared.

This paper presents an overview of a four-year project focused on development of an integrated computational materials engineering (ICME) toolset for third generation advanced high-strength steels (3GAHSS). Following a brief look at ICME as an emerging discipline within the Materials Genome Initiative, technical tasks in the ICME project will be discussed. Specific aims of the individual tasks are multi-scale, microstructure-based material model development using state-of-the-art computational and experimental techniques, forming, toolset assembly, design optimization, integration and technical cost modeling. The integrated approach is initially illustrated using a 980MPa grade transformation induced plasticity (TRIP) steel, subject to a two-step quenching and partitioning (Q&P) heat treatment, as an example.