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This paper presents experimental investigations of diagnosing and analyzing the low-frequency, low- SNR (Signal to Noise Ratio) noise sources of three motorcycles using a hybrid technology that consists of a passive SODAR (Sonic Detection And Ranging) and modified HELS (Helmholtz Equation Least Squares) methods. The former enables one to determine the precise locations of multiple sound sources in 3D space simultaneously over the entire frequency range that is consistent with a measurement microphone in non-ideal environment, where there are random background noise and unknown interfering signals. The latter enables one to reconstruct all acoustic quantities such as the acoustic pressure, acoustic intensity, time-averaged acoustic power, radiation patterns, and sound transmission paths through arbitrarily shaped vibrating structures.

Described in this paper is a component test methodology to evaluate the door trim armrest performance in an Insurance Institute for Highway Safety (IIHS) side impact test and to predict the SID-IIs abdomen injury metrics (rib deflection, deflection rate and V*C). The test methodology consisted of a sub-assembly of two SID-IIs abdomen ribs with spine box, mounted on a linear bearing and allowed to translate in the direction of impact. The spine box with the assembly of two abdominal ribs was rigidly attached to the sliding test fixture, and is stationary at the start of the test. The door trim armrest was mounted on the impactor, which was prescribed the door velocity profile obtained from full-vehicle test. The location and orientation of the armrest relative to the dummy abdomen ribs was maintained the same as in the full-vehicle test.

The simulation of I.C. Engines operation, especially during transients, requires a fairly accurate estimation of the internal mechanical losses of the engine. The paper presents generic friction models for the main friction components of the engine (piston-ring-liner assembly, bearings and valve train), considering geometry of the engine parts and peculiarities of the corresponding lubrication processes. Separate models for the mechanical losses introduced by the injection system, oil and water pumps are also developed. All models are implemented as SIMULINK modules in a complex engine simulation code developed in SIMULINK and capable to simulate both steady state and transient operating conditions. Validation is achieved by comparison with measurements made on a four cylinder, common rail diesel engine, on a test bench capable to run controlled transients.

A general numerical method, the so-called Fourier Spectral Element Method (FSEM), is described for the dynamic analysis of complex systems such as car body structures. In this method, a complex dynamic system is viewed as an assembly of a number of fundamental structural components such as beams, plates, and shells. Over each structural component, the basic solution variables (typically, the displacements) are sought as a continuous function in the form of an improved Fourier series expansion which is mathematically guaranteed to converge absolutely and uniformly over the solution domain of interest. Accordingly, the Fourier coefficients are considered as the generalized coordinates and determined using the powerful Rayleigh-Ritz method. Since this method does not involve any assumption or an introduction of any artificial model parameters, it is broadly applicable to the whole frequency range which is usually divided into low, mid, and high frequency regions.

A new friction testing system has been designed and built to simulate the actual engine conditions in friction and wear test of piston-ring and cylinder liner assembly. Experimental data has been developed as Friction Coefficient / Crank Angle Degree diagrams including the effects of running speed (500 and 700 rpm) and ring normal load. Surface roughness profilocorder traces were obtained for tested samples. Mixed lubrication regime observed in the most part of the test range. New cylinder bore materials and lubricants can be screened easily and more reliable simulated engine friction data can be collected using this technique.

Automobile disk brake squeal has always been one of the major customer complaints because of its extremely unpleasant, very high pitch and intense sound. Currently, diagnostics of vehicle brake squeals are conducted using a scanning laser vibrometer synchronized with squeals. This process is time consuming, especially when there is a hard-to-reach area for a laser beam to shine or when squeals have multiple frequencies for which filtering must be used so that individual out-of-plane vibration modes can be obtained. In this paper, a different method known as Helmholtz equation least squares (HELS) method based nearfield acoustical holography (NAH) is used to reconstruct all acoustic quantities, including the acoustic pressure, normal components of the surface velocity and acoustic intensity. In particular, the locations from which squeal is originated are identified and the out-of-plane vibration modes that are responsible for squeal sounds are established.

Experiments have revealed that the brain of the experimental animal behaves elastically in response to dynamic forces in situ. The response of the skull of the human cadaver has been investigated by means of static load-deflection tests and impact and mechanical impedance tests. This information has been used to construct a two-dimensional head model consisting of a polyester resin shell reinforced with fiberglas with plexiglass sides; a clear silicone gel brain; and spinal cord simulated by a plexiglass tube containing silicone gel supported by a piston-spring assembly. Several frames taken from motion pictures recorded at 7,000 frames/sec. show how pressure gradients in the model are displayed by observing the growth and location of bubbles during impact.

The boundary integral equation method (BIEM) of analysis was applied to problems involving beams, thick plates and stress concentration regions. Beam and plate problems were considered to provide guidelines for use of the three-dimensional BIEM to analyze brackets and other components which have “solid like” regions as well as regions which are “beam or plate like”. In unsubstructured form the BIEM produced results in excellent agreement with exact solutions from elasticity theory for plates with length/thickness ratios as large as 40. Loading cases included bending by terminal couples and flexure by terminal loads. Using substructuring, CP times were reduced. CP times for both the IBM 3084 and the CDC CYBER 205 were obtained, the influence of varying integration orders discussed, and techniques to assess the accuracy of computed results were described.

The boundary integral equation method (BIEM) of analysis was applied to problems involving thick plates and stress concentration regions. In unsubstructured form the BIEM produced results in agreement with exact solutions from elasticity theory for plates with length/thickness ratios as large as 40, for the case of bending by terminal couples. Using substructuring, CP times were reduced. CP times for the CDC CYBER 205 were obtained, and the influence of varying integration orders was discussed. The BIEM was also found to produce accurate stress concentration factors for tension, bending and torsion of a stepped round bar with a circumferential shoulder fillet.

An extensive experimental study of noise generating mechanisms of two production models of automotive alternators is presented. It was established that aerodynamic noise (generated by cooling fans) is dominating at high speeds (above 3,000 rpm), while electromagnetic noise is the most intensive at low rpm. Two directions of noise reduction are proposed and validated: reduction of noise levels generated by alternators to be achieved by using axial flow fans for cooling instead of presently used bladed discs, and radical reduction of operating speed of alternators by using variable transmission ratio accessory drives.

A new algorithm for carrier removal, a key step in the Fourier transform method of fringe pattern analysis, is presented in this paper. The accuracy of frequency estimations is critical to carrier removal to avoid potential significant errors in the recovered phase. A new algorithm on Fourier transform and curve fitting technique is developed. To avoid an ill-conditioned result in solving the least-square problem, an orthogonal polynomial curve fitting algorithm is developed. A new system that combines projected grating moiré (PM) with shadow moiré (SM), recently designed and built with large dynamic range for both component level and board level warpage measurement for the reliability study of electronic packaging materials and structures, is presented and demonstrated.

The adoption of lithium-ion batteries in vehicle electrification is fast growing due to high power and energy demand on hybrid and electric vehicles. However, the battery overall performance changes with time through the vehicle life. This paper investigates the electric vehicle battery cell aging under different usages. Battery cell experimental data including open circuit voltage and internal resistance is utilized to build a typical electric vehicle model in the AVL-Cruise platform. Four driving cycles (WLTP, UDDS, HWFET, and US06) with different ambient temperatures are simulated to acquire the battery cell terminal currents. These battery cell terminal current data are inputs to the MATLAB/Simulink battery aging model. Simulation results show that battery degrades quickly in high ambient temperatures. After 15,000 hours usage in 50 degrees Celsius ambient temperature, the usable cell capacity is reduced up to 25%.