Impact behaviors of aluminum honeycomb sandwich panels (AHSPs) are investigated experimentally by using a drop weight test setup. The specimens of 12.7 mm cell size were tested by impacting at four different initial contact points, namely face center, corner, long edge and short edge of core cells, with two impactors of weights 5.25 kg and 11.9 kg, respectively. Dynamic nonlinear transient analysis was also carried out by a finite element simulation model developed based on continuum damage mechanics to account for nonlinear and elastoplastic behavior. The results revealed that while the impact behaviors of AHSPs were nearly the same for low impact energy, they were different for high impact energy. The peak resistance force of AHSPs was the highest for impact at the face center and the lowest for impact at the short edge of the core cells. The results of FE simulation revealed that the real time deformation produced fracture when the crack initiated and propagated to the honeycomb core from the facesheet.

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It is well-known that the noise and vibration from the torque change of the engine and the inertia change of its accessories (alternator and water pump) have severe effects on both the quality and the life expectancy of the engine belt system. An automatic belt tensioner is generally used not only to reduce the noise and vibration of such belt system, but also to enhance the life cycle. In the present research, measurement of the user running conditions and the data analyses were performed to try to derive an evaluation method of life cycle of such an automatic belt tensioner system. As a part of results, a running condition for the evaluation was suggested from the study of conditions loaded on an automatic belt tensioner. This running condition was divided into two parts, the Structure part and the Pulley one, and suggested separately for the accelerated life-test of the system. As the other part of the results, an accelerated life-test condition was derived using Palmgen-Miner rule for structure part. And a modified accelerated life-test condition, which uses temperature as an acceleration factor, was suggested for pulley part.

Time domain approach with S-N approach and local strain approach were used for fatigue life estimation. But these days, using PSD (Power Spectral Density) method is highlighted, because of short amount of time in measurement and analysis. Especially, PSD method is useful for analysis of fatigue failure which is caused by vibration damage, also FRF (Frequency Response Function) is useful for efficient prediction of fatigue life when the same product is employing different motor vehicle or test condition. In order to estimate fatigue life of compressor for air conditioning, time domain analysis and frequency domain analysis were performed and the results were compared. As a result, results of analysis in frequency domain and time domain were similar. With this, there is recognition of decreasing the period of measuring and analysis in PSD analysis. Moreover, in case of FRF pursued of a part, using FRF is applicable at fatigue life prediction in different testing condition. There was investigated an analysis method with curtailed analysis period by FRF.