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Finite element modeling has been used extensively nowadays for predicting the noise and vibration performance of whole engines or subsystems. However, the elastomeric components on the engines or subsystems are often omitted in the FE models due to some known difficulties. One of these is the lack of the material properties at higher frequencies. The elastomer is known to have frequency-dependent viscoelasticity, i.e., the dynamic modulus increases monotonically with frequency and the damping exhibits a peak. These properties can be easily measured using conventional dynamic mechanical experiments but only in the lower range of frequencies. The present paper describes a method for characterizing the viscoelastic properties at higher frequencies using fractional calculus. The viscoelastic constitutive equations based on fractional derivatives are discussed. The method is then used to predict the high frequency properties of an elastomer.

Gear tooth friction directly influences power losses and temperature rise as well as system dynamic behavior. Recently it attracted many attentions as friction is considered one of the main sources of power losses in geared systems, such as in automotive transmissions. Coefficient of friction has been found not a constant but varies with different contact conditions, which partly makes the measurement of friction a difficult and expensive process. Therefore an analytical model that is capable of predicting it accurately becomes very much demanded. A few empirical formulae based on experimental data and analytical models based on lubrication theory are found in the literature. However, they are either not suitable for a general gear contact or too complex to adapt in gearing. In this paper, a new coefficient of sliding friction based on a thermal Elastohydrodynamic Lubrication (EHL) model is developed by a multiple linear regression analysis.

Hydroformed components are replacing stamped parts in automotive frames and front end and roof structures to improve the crash performance of vehicles. Due to the increasing application of hydroformed components, a better understanding of the crash behavior of these parts is necessary to improve the correlation between full-vehicle crash tests and FEM analysis. Accurately predicting the performance of hydroformed components will reduce the amount of physical crash testing necessary to develop the new components and new vehicles as well as reduce cycle time. Virgin material properties are commonly used in FEM analysis of hydroformed components, which leads to erroneous prediction of the full-vehicle crash response. Changes in gauge and material properties during the hydroforming process are intuitive and can be reasonably predicted by using forming simulations. The effects of the forming process have been investigated in the FEA models that are created for crash analyses.

Fatigue testing of components is used to validate new product designs as well as changes made to existing designs. On new designs it is common to initially test parts at the design stage (design verification or DV) and then again at the production stage (production verification or PV) to make sure the performance has not changed. On changes to existing designs typically the life of the new part (B) is compared to that of the old part (A). When comparing the fatigue life Weibull analysis is normally used to evaluate the data. The expectation is that the B10 or B50 life of the new part or PV parts should be equal to or better than that of the old parts or the DV parts. However, fatigue testing has a great deal of inherent variability in the resulting life. In this paper the variability of numerous carburized and induction hardened components is examined.

Shaft surface texture plays a very important role in rotary oil seal system performance. Functionally, the shaft surface has to prevent oil leakage via pumping between the shaft and seal. The shaft surface texture must also provide adequate contact with the seal lip, while maintaining a lubricant film. Furthermore, the initial surface texture of the shaft plays a vital role in the process of oil seal lip break-in. The shaft surface finish specification is typically Ra, 10 to 20 μ″ with a 0° ± 0.05°lead angle. The paper will describe a new surface measurement method based on interference microscopy, which generates a visual representation of a significant portion of the shaft surface texture to allow direct lead angle detection. Using this new technique, this paper will demonstrate the heredity of lead generation. The shaft 3D surface texture measurement also provides a measure of the surface volume available for lubricant retention.

The objective of this work is to test and develop monotonic tensile properties and strain controlled fatigue properties of a cast ductile iron. The test data and the related material constants will be used in conjunction with vehicle loading data to perform finite element stress-strain analysis and fatigue life prediction analysis to aid in the design of automotive components made from ductile iron. Currently, such material property data does not exist in the literature for this particular grade of ductile iron. Monotonic tension and fully reversed strain controlled fatigue tests were conducted by following ASTM E-8, ASTM E-606, and SAE J-1099 on samples machined from the cast ductile iron. Monotonic tensile properties were obtained, including Young's modulus, yield strength, ultimate tensile strength, elongation, reduction in area, strength coefficient K, and strain hardening exponent n.

Traditional methods often lead to truck component designs that are overly conservative. The ever-increasing need to reduce operational costs demands innovative means for producing parts that are light, durable and capable of carrying more loads. This paper discusses the far-reaching advantages of shape-optimization, beyond the fundamental stipulation of weight reduction. A suspension link is considered to demonstrate the benefits of an optimally shaped component.

In this study, the finite element analysis of hydroform tooling system using three different surface-to-surface contact methodologies is evaluated, such as the traditional non-linear gap element methodology, the newer linear gap technology and the 3D non-linear surface contact algorithm. These methods are investigated with the help of case studies, from exercise model level to more complicated models of real parts. Key parameters like analysis results, computational time and ease of use for each method are discussed. Directions regarding adaptivity to local user’s software resources and implementation strategies are provided. The linear gap method is observed to be more effective as pre-processing and computing time with same accuracy results as the non-linear static method in the design stage of hydroform tools analysis with pure sliding.

As a part of a major research program with the aim of improving heavy truck drive axle fuel efficiency, this work focuses on seal friction torque test development and establishing pinion seal and wheel seal friction torque baseline data. Pinion seal and wheel seal friction torque was measured. The effect of speed and temperature on pinion seal friction torque was assessed. The effect of several coatings on pinion seal friction torque was evaluated. Pinion seal friction torque was also calculated and calculation result was compared with test data. Finally the impact of seal friction and bearing friction on total drive axle power loss was discussed.

Microwave plasmas at atmospheric pressures can be utilized for carburization of steel alloys. Due to their high frequencies, microwaves ionize and dissociate molecules with great efficiency and provide carbon for carburization by dissociating hydrocarbons that are introduced in the plasma. Also, conventional carburization techniques are not very energy efficient, as much of the heat generated is not utilized for the heating of the parts. Microwave plasmas are highly energy efficient due to very high coupling of microwaves to the plasma and then transferring of heat to the parts. Since plasma surrounds the part uniformly, heating rates over the part surface are also uniform. Preliminary results are presented for carburization of steel alloy 8620H by atmospheric microwave plasma process using acetylene as the source gas. Possible effects of application of pulsed DC bias to the parts are also discussed.

Compression is a key design attribute of both compressible seals and coupled hose systems. Traditional design techniques use 3-sigma upper and lower limits from capability studies on critical component dimensions to estimate potential compression variation. Probability calculations are shown that indicate that the true variation in compression is much less than this estimate. An alternative approach using probabilistic design techniques to calculate true 6-sigma (+/-3-sigma) compression variation is shown for both a typical radial seal and a hose coupling. The results are then compared to Monte Carlo simulations using representative data sets for each critical dimension.

Vehicular suspension ball joints can be categorized in the family of tribological systems which can reduce useful service or working capacity through malfunction or breakdown. Detailed metallurgical analysis of the friction and wear mechanisms on typical ball joint bearing surfaces point to a Teflon-based woven fabric, self-lubricating liner as the best bearing material for the joint. Laboratory functional testing was conducted on modern, 4-axis test equipment simulating the applicable loading and motion conditions typically encountered in use. The self-lubricated bearing liner woven with Teflon thread demonstrated higher sustained load capacity, less rotating friction, excellent torque retention qualities and extended life in comparison to existing components utilizing greased metal-on-metal and/or “plastic” bearing materials.

The method presented utilizes the analytical design model and matrix algebra to determine the load required to close a design gap. By performing a linear analysis in MSC® Nastran, relative displacements at fastener contact points due to unit loading are collected. The stiffness equation, F = K x is used in matrix form to determine gap closure force. The effect of this force on preload should be considered in torque specifications. The method prevents overestimation of preload if closure force is not considered and underestimation if only the stiffness equation is used independently.

This paper will describe the development of an accelerated testing methodology for an off-highway vehicle rotary oil seal system. There are two typical field failure mechanisms associated with off-highway input pinion shaft oil seals: 1) excessive abrasive wear of soft seal lip and hard shaft surface due to abrasive environment; 2) excessive heat and degradation of the seal lip due to lack of lubricity and wear of the shaft surface run against this seal. The accelerated testing of the rotary oil seal consisted of a combination of the following factors; shaft run-out, eccentricity, testing temperature, rotation and reciprocal motion of the seal lip relative to the shaft surface. The combination of these factors especially reciprocal motion reproduces the same failure mechanism, i.e. shaft wear grooves and oil seal lip wear observed on the field usage samples with 6,300 hours service in only 350 hours of accelerated testing.