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Nonlinear finite element (FE) collapse pressure predictions are compared to experimental results for submarine pressure hull test specimens with and without artificial corrosion and tested to collapse under external hydrostatic pressure. The accuracy of FE models, and their sensitivity to modeling and solution procedures, are investigated by comparing FE simulations of the experiments using two different model generators and three solvers. The standard FE methodology includes the use of quadrilateral shell elements, nonlinear mapping of measured geometric imperfections, and quasi-static incremental analyses including nonlinear material and geometry. The FE models are found to be accurate to approximately 11%, with 95% confidence, regardless of the model generator and solver that is used. Collapse pressure predictions for identical FE models obtained using each of the three solvers agree within 2.8%, indicating that the choice of FE solver does not significantly affect the predicted collapse pressure. The FE predictions are found to be more accurate for corroded than for undamaged models, and neglecting the shell eccentricity that arises due to one-sided shell thinning is found to significantly decrease the resulting accuracy of the FE model. 相似文献
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M. S. Xie G. R. Zhang J. H. Li R. Fritsch 《International Journal of Automotive Technology》2014,15(4):565-571
Automotive brake systems today have many factors that can contribute to brake noise. Modern approaches to reduce the propensity of brake noise mostly target high frequency brake squeal. A more difficult constituent of brake noise to address is low frequency moan, which is typically caused when the brake system excites a suspension member with a constrained natural frequency in the range of excitation. Although most modern CAE techniques utilized to diagnose and solve brake noise issues focus on new brake pad condition, this paper will show the benefit of understanding a common wear mechanism “Taper Wear,?and attempt to correlate its effects on brake moan. In order to study this phenomenon, a finite element model of a disc brake is established, and a complex eigenvalue analysis (CEA) of the brake system is performed. The propensity of brake moan noise is evaluated on basis of damping ratio of a dynamic brake system model. By using the finite element model, effects of the brake pad taper wear on brake moan noise is studied. The results show that the brake pad taper wear is a significant factor for generating the instability causing the brake moan noise. The study is performed at various levels of brake pad taper wear. When the brake pad taper wear is more than 0.5 mm, the value of negative damping ratio rapidly increases, and the propensity of brake moan noise is greatly magnified. In this study, the simulation result correlated well with the test result, which provides the theory and guidance for brake moan noise control. 相似文献
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J. E. Taylor M. Amor-Segan G. Dhadyalla R. P. Jones 《International Journal of Automotive Technology》2014,15(3):441-449
This paper suggests a novel approach to finding faults in a vehicle’s electronic systems by monitoring the network traffic directly and generating statistical traits. The nature of the data in a CAN network is considered, and a case for the use of statistical analysis presented. Statistical traits extracted from the temporal behavior of network messages are investigated as a metric for fault detection. It is shown how this trait information can be extracted from network data, and how this information could be used for fault detection of an unknown fault on a CAN network. It is then demonstrated that combining multiple types of trait data can be used to correctly identify a fault once detected. 相似文献
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研究了复合材料曲梁在受到合拢弯矩作用下发生的屈曲情况,并给出一种理论解析方法来分析这种很可能发生在复合材料弯曲结构中的脱层耦合屈曲问题.该方法是基于曲梁大变形理论及断裂力学而提出来的.文中并用该解析方法分析了一个特定的常见的情况,在该题例中脱层发生在非常靠近内表面处并且突变屈曲就发生在该薄脱层.在文中也对脱层裂纹的弧角对极限载荷的影响进行了研究. 相似文献
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R. O. Goss 《Maritime Policy and Management》1984,11(4):223-226
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R. H. Burroughs 《Maritime Policy and Management》1984,11(4):269-276
Over the last 13 years the sampled offshore workboat fleet has nearly doubled in size and vessels types have shifted to meet new work requirements. Maritime employment on these vessels may be equivalent to 8% of the world total for vessels over 100 get and is expected to grow. In the United States over the last 34 years the number of new jobs created in this activity approximates the number of jobs lost from the decline of us flag deepsea vessels. Vessels have been, and continue to be, administered primarily by us firms although a substantial broadening of international participation occured with the development of the North Sea and may also occur in the Far East. Expanding offshore development, a function of where remaining petroleum reserve lie, will require technological changes for success in deeper water and/or ice conditions. 相似文献