Automotive Science and Engineering

Off-road cars’ windshields are vulnerable to different types of stones, road debris and pebbles due to common off paved and gravel surfaces in which they drive. Any attempt to design windshield that minimizes injury and death of occupants during a vehicle accident requires a thorough understanding of the mechanical behavior of automotive windshield subjected to foreign object impact loads.

In this study, some drop ball tests in different impact energy levels are conducted in order to monitor fracture behavior of an off-road automotive windshield. Also dynamic crack patterns of laminated glasses are examined based on the impact energy levels and impact conditions. In addition, the acceleration which is imposed to impactor during the accident is recorded. The experimental results are compared to an analytical approach regarding the resultant impact force as well. There is a good agreement between the impact forces of experimental test results and analytical approaches ones. All in all, in low velocity impacts, impact energy releases through powdering region in impact area, radial cracks and strain energy in PVB. It is concluded that in lower impact energy levels, the higher impact speed, the more number of radial cracks. In addition, at higher energy levels, number of radial cracks decease due to higher strain energy levels in PVB interlayer. Therefore, in low velocity impacts, number of radial cracks has reverse relationship with penetration depth in PVB interlayer.

Although, the Stirling engine (SE) was invented many years ago, the investigation on SE is still interesting due to variety of energy resources can be applied to power it (solar energy, fossil fuel, biomass and geothermal energy). In this paper, the thermodynamic cycle of SE is analyzed by employing a new analytical model and a new method is presented to evaluate output power and efficiency of real engines. Using the correcting functions; represent more accurate results for known Schmidt equations respect to adiabatic model. So without need to employing numerical methods and iterative solver programs, analogous results with accuracy and correctness of open-form solution-adiabatic method is obtained. The modeling of results of two methods is done by Non-linear Multiple Regression and new equations based on Schmidt equations with new correctness factors is presented. The correctness factors are function of structural and operational characteristics of engine.  Moreover, available output data of GPU-3 SE was compared. These comparisons show good agreement, indicating that the model is an appropriate method for modeling of SE outputs.