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Coatings have the potential to improve bearing tribological performance. However, every coating application process and material combination may create different residual stresses and coating microstructures, and their effect on bearing fatigue and wear performance is unclear. The aim of this work is to investigate coating induced residual stress effects on bearing failure indicators using a microstructural contact mechanics (MSCM) finite element (FE) model. The MSCM FE model consists of a two-dimensional FE model of a coated bearing surface under sliding contact where individual grains are represented by FE domains. Interactions between FE domains are represented using contact element pairs. Unique to this layered rolling contact FE model is the use of polycrystalline material models to represent realistic bearing and coating microstructural behavior. The MSCM FE model was compared to a second non-microstructural contact mechanics (non-MSCM) model.

This study is concerned with computational fluid dynamics (CFD) simulations of flow in an automotive reverse flow type cyclone particle separator using the Reynolds Stress Model (RSM) turbulence model. Steady simulations were found to never fully converge, with pressure, velocity and vorticity results exhibiting small oscillations as the solution was iterated further. Transient simulations showed the presence of a main vortex precession that resulted in periodic fluctuations of the flow parameters. Fourier analysis was used to characterize this semi-periodic flow feature and to assess its effect on the two main performance measures of the cyclone: overall pressure drop and particle separation efficiency.

Predicting the optimum performance parameters of an automotive cyclone particle separator (separation efficiency and pressure drop) using computational fluid dynamics by varying its geometrical parameters is challenging and a time consuming process due to the highly swirling nature of the flow. This study presents results of three investigations of the performance and design of a cyclone separator: a sensitivity analysis, deterministic optimization and a reliability based design optimization. All three cases involved variation of four geometric parameters that characterize the design of the cyclone.

With increased demand for improvements in the efficiency and operation of all automotive engine components, including those in the engine cooling system, there is a need to develop a set of virtual tools that can aid in both the evaluation and design of automotive components. In the case of automotive radiators, improvements are needed in the overall pressure drop as well as the coolant flow homogeneity across all radiator tubes. The latter criterion is particularly important in the reduction of premature fouling and failure of heat exchangers. Rather than relying on ad hoc geometry changes with the goal of improving the performance of radiators, the coupling of CFD flow simulations with numerical shape optimization methods could assist in the design and testing of automotive heating and cooling components.

Improvements in the pressure drop across and flow homogeneity in the tubes of automotive radiators are needed to reduce the power demands on the vehicle water pump and increase the lifetime of the radiator. The goal of this ongoing work is to develop a set of virtual tools coupling CFD flow simulations with numerical shape optimization methods to assist in the design and testing process of automotive heating and cooling components. In SAE paper 2002-01-0952, “Towards Shape Optimization of Radiator Cooling Tanks,” the authors developed and evaluated optimization criteria for pressure drop and mass flow rate distribution in a water-to-air automotive heat exchanger. In this follow-up paper, results based on the implementation of these optimization criteria are presented. More specifically, results concerning the placement of radiator inlets and outlets are addressed.

Mobility in the automotive and transportation sectors has been experiencing a period of unprecedented evolution. A growing need for efficient, clean and safe mobility has increased momentum toward sustainable technologies in these sectors. Toward this end, battery electric vehicles have drawn keen interest and their market share is expected to grow significantly in the coming years, especially in light-duty applications such as passenger cars. Although the battery electric vehicles feature high performance and zero tailpipe emission characteristics, economic and technical issues such as battery cost, driving range, recharging time and infrastructure remain main hurdles that need to be fully addressed. In particular, the low power density of the battery limits its broad adoption in heavy-duty applications such as class 8 semi-trailer trucks due to the required size and weight of the battery and electric motor.

The need for transient thermal simulations in vehicle packaging studies has grown rapidly in recent years. To date, the computational costs associated with the transient simulation of 3D conjugate heat transfer phenomena has prohibited the widespread use of full vehicle transient simulations. This paper presents results from a recent study that explored a method to circumvent the computational costs associated with long transient conjugate heat transfer simulations. The proposed method first segregates the thermal structural and fluid physics domains to take advantage of time scale differences. The two domains are then re-coupled to calculate a series of steady state conjugate heat transfer simulations at various vehicle speeds. The local convection terms are then used to construct a set of surrogate models dependent on vehicle speed, that predict the local heat transfer coefficients and the local near wall fluid temperatures.

This paper presents the measurement and analysis of the edge stretching limit of aluminum alloy using digital image correlation. The edge stretching limit, also known as the “edge thinning limit,” is the maximum thinning strain at a point of edge failure resulting from tension; which may be predisposed by edge quality. Edge fracture is a vital failure mode in sheet metal forming, however it is very difficult to measure. A previous study enabled the measurement of edge thinning strain by using advanced digital image correlation but it did not consider how the edge quality could affect the edge stretching limit of aluminum alloy. This paper continues to measure edge thinning strain by comparing polished to unpolished AA5754, thus determining the effect edge quality has on the edge stretching limit. To enable the measurement by optical method for a very long and thin sample, a notch is used to localize where edge failure occurs.