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Dent resistance is an important attribute in the automotive panel design, and the ability to accurately predict a panel's dentability requires careful considerations of sheet metal properties, including property changes from stamping process. The material is often work-hardened significantly during forming, and its thickness is reduced somewhat. With increased demand for weight reduction, vehicle designers are seriously pushing to use thinner-gauged advanced high-strength steels (AHSS) as outer body panels such as fenders, hoods and decklids, with the expectation that its higher strength will offset reduced thickness in its dentability. A comparative study is conducted in this paper for a BH210 steel fender as baseline design and thinner DP500 steel as the new design.

This study investigates and compares fatigue behavior of forged steel and powder metal connecting rods. The experiments included strain-controlled specimen testing, with specimens obtained from the connecting rods, as well as load-controlled connecting rod bench testing. Monotonic and cyclic deformation behaviors, as well as strain-controlled fatigue properties of the two materials are evaluated and compared. Experimental S-N curves of the two connecting rods from the bench tests obtained under R = -1.25 constant amplitude loading conditions are also evaluated and compared. Fatigue properties obtained from specimen testing are then used in life predictions of the connecting rods, using the S-N approach. The predicted lives are compared with bench test results and include the effects of stress concentration, surface finish, and mean stress. The stress concentration factors were obtained from FEA, and the modified Goodman equation was used to account for the mean stress effect.

A drag dynamometer was used to evaluate the performance of automotive brake drums made from four kinds of materials with different thermal conductivities. In the order of decreasing thermal conductivity they are chromium copper, aluminum/cast iron composite, cast iron, and nickel-aluminum bronze. All of the drums were of the standard configuration used in SAE J 661a, or closely approximated it. The drums were run in conjunction with three types of lining materials: nonabrasive, moderately abrasive, and highly abrasive. Temperatures near the lining/drum interface, coefficients of friction, and lining wear were measured and compared. For a given amount of work done, the temperature near the drum surface was found to be lowest for the chromium copper drums, with progressively higher temperatures in the aluminum/cast iron composite, nickel-aluminum bronze, and cast iron drums. Relative lining wear and coefficient of friction varied with the type of lining tested.

In order to reduce fuel consumption, companies have been looking at hybridizing vehicles. So far, two main hybridization options have been considered: electric and hydraulic hybrids. Because of light duty vehicle operating conditions and the high energy density of batteries, electric hybrids are being widely used for cars. However, companies are still evaluating both hybridization options for medium and heavy duty vehicles. Trucks generally demand very large regenerative power and frequent stop-and-go. In that situation, hydraulic systems could offer an advantage over electric drive systems because the hydraulic motor and accumulator can handle high power with small volume capacity. This study compares the fuel displacement of class 6 trucks using a hydraulic system compared to conventional and hybrid electric vehicles. The paper will describe the component technology and sizes of each powertrain as well as their overall vehicle level control strategies.

Non-Asbestos Organic (NAO) disc pads and Low Steel Lomet disc pads were subjected to high and low humidity conditions to discover how humidity affects these two classes of formulations for physical properties, friction, wear and noise characteristics. The 2 classes of formulations show similarities and differences in response to increasing humidity. The humidity effect on deformation of the surface microstructure of the gray cast iron disc is also investigated. Humidity implications for pad quality control and brake testing are discussed.

Two different aluminium alloy materials have been used to produce ventilated brake discs, on one hand, AS17G0.6 hypereutectic alloy and on the other hand, AS7G0.6 reinforced with 20% in wt. of SiC particles. The casting production technique used has been Low Pressure Casting (LPC) and some of the brake discs have been heat treated using a T6 treatment. Once the ventilated brake discs were produced and machined, they were tested in a dynamometer in order to compare the performance under service conditions of the aluminum alloy and grey cast iron (GCI) discs currently used in the market.

The present work compares the tribological properties of ZnO (Zinc Oxide) nanoparticle based lubricant with ZDDP (zinc dialkyl dithiophosphate) based lubricant. The nanolubricant was prepared by mixing the nanoparticles in base oil followed by ultrasonification and ZDDP based lubricant was prepared by mixing ZDDP and stirring with base oil. Base oil used was mineral base oil. Both the lubricants were tested at three different temperatures, loads and roughness values. The test was carried out on AISI 52100 steel samples prepared by wire cutting and were grinded to three different levels of surface roughness. Friction and wear tests were performed using a reciprocating sliding tribo-tester at three different loads and temperatures. Taguchi orthogonal array was used to reduce the number of experiments. SEM, EDS and AFM analysis were carried out to study the surface wear phenomenon.

Damping measurements on vehicle subsystems are rarely straightforward due to the complexity of the dynamic interaction of system joints, trim, and geometry. Various experimental techniques can be used for damping estimation, such as frequency domain modal analysis curve-fitting methods, time domain decay-rate methods, and other methods based on energy and wave propagation. Each method has its own set of advantages and drawbacks. This paper describes an analytical and an experimental comparison between two, widely used loss factor estimation techniques frequently used in Statistical Energy Analysis (SEA). The single subsystem Power Injection Method (PIM) and the Impulse Response Decay Method (IRDM) were compared using analytical models of a variety of simulated simple spring-mass-damper systems. Frequency averaged loss factor values were estimated from both methods for comparison.

A unique opportunity arose to make a direct comparison of aluminum, sheet molding compound (SMC) and steel using a common hood design. In considering all possible material combinations of inner and outer panels, it was discovered that some of the combinations were incompatible due to material properties. Only the compatible material combinations were considered. Three different joining techniques - welding, bonding and bonded hem flanging - were evaluated. The cost, weight and structural performance of the chosen hood material combinations were established. Areas of further development were identified, including design optimization for specific material combinations.

Various galvanized steels, ZINCROMETAL and cold-rolled steel were painted with automotive-type paints and tested via accelerated, atmospheric and on-vehicle tests. Tests indicate that the ASTM B117 salt fog test and the Kesternich SO2 test do not yield results which are indicative of automotive, in-service corrosion performance. A modified Volvo scab corrosion test was found to offer an accelerated method to accurately predict automotive, in-service corrosion performance. Galvanized steels exhibited corrosion resistance which was far superior to ZINCROMETAL and cold-rolled steel. Thicker zinc coatings on steel were found to offer better corrosion protection to painted substrates.

Environmentally friendly fuels and lubricants research on hydraulic fluids, engine oils, greases and industrial applications is of interest to government agencies and manufacturers of equipment, engines and vehicles. The key to increasing the use of renewable natural resources is developing fluids of equivalent performance to petroleum base products, at an acceptable product cost. The well known drawbacks of vegetable oils are oxidation stability and low temperature properties. This study compares commercial fluids and laboratory formulations as to their rheological properties and uses different approaches to solve both the low temperature and the oxidative stability problems. Frictions and wear characteristics of the fluids are evaluated and several fluids are compared laboratory bench tests.

This paper discusses the contribution of instrument panel systems in a European side-impact event. Systems studied include a conventional steel cross-car beam system and a glass-mat thermoplastic (GMT) composite system, evaluated in a body-in-white structure. A thermoplastic composite instrument panel system offers mass, cost, and recycling benefits, but its performance vs. a conventional steel cross-car beam system merited an engineering investigation. The comparison methodology used included a nonlinear dynamic side impact study with a moving, deformable barrier developed according to European Economic Community (EEC) standards. A finite-element model used in this study simulated the body-in-white structure, barrier structure and instrument panel systems. The resulting data include velocity, displacement and energy absorption levels of various components of the respective instrument panel systems.

Hat-sections, single and double, made of steel are frequently encountered in automotive body structural components. These components play a significant role in terms of impact energy absorption during vehicle crashes thereby protecting occupants of vehicles from severe injury. However, with the need for higher fuel economy and for compliance to stringent emission norms, auto manufacturers are looking for means to continually reduce vehicle body weight either by employing lighter materials like aluminum and fiber-reinforced plastics, or by using higher strength steel with reduced gages, or by combinations of these approaches. Unlike steel hat-sections which have been extensively reported in published literature, the axial crushing behavior of hat-sections made of fiber-reinforced composites may not have been adequately probed.

This paper describes the results of a series of fatigue studies relating the lives of several weld geometries. Rotating beam and axially loaded specimens were used. A comparison between steel and plastic (polyvinylchloride scale models is made. Using plastic scale models of welded structures for fatigue life determination is the ultimate goal of this work.

Atomized iron powder was screened to narrow fractions and annealed. Intermetallic Fe3P powder was blended with the fractions to provide an alloy containing 0.45% phosphorus after sintering. Cores were pressed to a density of 7.4 g/cm3 and sintered at temperatures ranging from 1600°F (870°C) to 2600°F (1430°C) in hydrogen. Magnetic properties were determined from the sintered cores and compared with previous properties measured for iron and hot repressed 0.45% phosphorus iron. It was found that the induction at any density level was approximately 500 gausses (0.05 teslas) lower than for iron. Remanent magnetization was influenced by the size of the pores. If pores were large, remanent magnetization was 8 K gausses (0.8 teslas) and increased to 12 K gausses (1.2 teslas) as the pores become finer. Both maximum permeability and the coercive force were improved when 0.45% phosphorus was added.

Continuing pressure to reduce mass and cost of vehicles is driving the development of new high strength steel products with improved combinations of strength and formability. Galvanized, cold rolled dual phase steel products are new alternatives to conventional high strength low alloy (HSLA) steel for strength limited applications in vehicles. These steels have higher tensile strengths than HSLA products with nearly equivalent formability. This paper compares the performance of HSLA and dual phase sheet steel products in a series of drop tower tests. Samples were prepared by stamping the steel sheets into typical rail-type parts using a production-intent die process. The parts were sectioned, and subsequently fabricated into hat-shaped assemblies that were then dynamically crushed by a drop weight. The experiments were designed such that the entire energy input by the drop weight was absorbed by the samples.

It is often said that heavier cars are inherently safer than lighter ones. However, when all cars are built with steel, larger size necessarily implies greater weight, so it is unclear whether the improved safety correlates to the weight or size of the vehicle. Using a publicly available computer model of the Ford Taurus, it was thought that this perception could be tested. The existing steel model, with the addition of a Hybrid III dummy and driver side airbag, was validated against actual crash test data. The structure was converted to aluminum, structural stiffness was calculated, and the steel and aluminum crash simulation results were compared. The aluminum model, utilizing monocoque sheet structure, weld bonded joining, and tailor welded blanks, weighed 200 kg less than the steel model and performed as well.

The tribology of different DLC coatings is studied through different mechanical and tribological tests like micro-hardness, scratch tests, friction in different oils, dry friction and impact-wear tests. The different tests reveal that hydrogen-free DLC coatings exhibit high hardness and low friction coefficient against steel, in boundary lubrication regime. Unfortunately, the remarkable tribological properties of tetrahedral amorphous carbon (ta-C) coatings are balanced by a low fracture toughness and low endurance behaviour, which affect the durability of coated mechanical components.

Mobile hydraulic systems traditionally operate under severe conditions in a wide range of climates. The component manufacturer's prime consideration in the selection of hydraulic oils for such service is the successful operation of the hydraulic system. Knowledge of his components and broad experience gained in their utilization emphasizes certain characteristics of oils that will aid the manufacturer in wedding the hardware into a system meeting the design criteria. Many types of oils, other than those specifically formulated for hydraulic systems, are being used for mobile hydraulic service. Among the more widely used are automotive and diesel engine oils and automotive transmission fluids. The major properties and characteristics of the fluids to be considered are wear protection, viscosity, fluid stability, rust protection, and filterability. These factors will be discussed in reference to their effect on component and system operation.

“Today, wearing parts are regularly subjected to abnormal loading conditions. They must be able to accept these conditions without failure. In continuous operations, unscheduled downtime greatly increases maintenance costs, not to mention the cost of lost production. White iron castings offer premium abrasion resistance for many of these applications, but are often not used due to the possibility of brittle failure and the difficulty of mechanical attachment. This paper discusses the properties and applications of a composite of martensitic white iron and mild steel. This laminate will accept medium to high impact without loss of service failure, and can be installed by mechanical means or with welded attachment.”