Spectral strip analysis for composite cylinders subjected to lateral impact
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An efficient computational method, combining the spectral element and the finite-strip method (spectral-strip) is developed in order to obtain numerical results to time dependent problems of cylindrical composite structures subjected to lateral impact, within moderate CPU times. The finite strip method is applied to cylindrical structures uses global interpolation in the circumferential direction, and spectral emenents in the meridional cross section. A term superposition solution is obtained, where every iteration refines the solution and is independent of former iterations. In this manner, a full three-dimensional solution to the problem of the dynamic response of cross-ply cylindrical composite shells subjected to a lateral impact, is obtained. The stability and the accuracy of the method are examined. The main goal is to predict the damage caused by a high velocity non penetrating impact of microparticles.
Two types of shells are studied—thin and thick cross-ply laminates. The effect of curvature on a high velocity impact is studied. Also, the stress field obtained by the finite element code is investigated and damage evaluation is discussed. The present work focuses on moderate and high velocity impacts and therefore the force duration is of the order of the through-the-thickness propagation time, causing the imapct region to be in tension due to the reflected stress wave. The results demonstrate the dilatational compression wave traverses the shell thickness as a result of the impact and the dilatational tension wave reflected from the interior free surface as well as the propagation of shear waves in different directions. Using failure criteria, one can find that the compressive stress wave causes matrix cracking and the tensile stress wave causes both delamination and matrix cracking. It is shown that for a thin cylinder, the impact phenomenon is concentrated near the striking region while for a thick-walled cylinder the results of the impact are visible in points far from the striking point as well. The interference of the stress waves that circumevent the cylinder create other points of local maxima for the equivalent stresses.
The code written for the finite element solution embloys the object oriented programming through the C++ language. A special matrix class is developed to perform various linear algebra operations.
KeywordsCylindrical Shell Radial Stress Spectral Element Spectral Element Method Lateral Impact
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- Avrashi, J.; Marom, D. 1994: Special strip and transition elements for modeling stress concetration regions in laminates. In Proc. 1st Int. Conf. Composite Eng. (ICCE/1), New Orleans, Louisiana USA, pp. 619–620Google Scholar
- Ben-David, D. 1995: Finite Strip Analysis of Composite Cylindrical Pressure Vessels Subjected to Lateral Impact. D.Sc. Thesis, Technion Israel Institute of Technology, Haifa, (in English)Google Scholar
- Maday, Y.;Patera, A. T. 1989: Spectral element method for the Navier-Stokes equations. In State of the Art Surveys in Computational Mechanics, pages 71–143. ASME, New YorkGoogle Scholar
- Marom, D.; Avrashi, J.; 1994: Substructuring of composite panels—mixed grids of elements, strips and transition strip elements. In 25th Israel Conference on Mechanical Engineering, HaifaGoogle Scholar
- Zrahia, U. 1993: Space-Time Spectral Element Method for Dynamic Analysis of Composite Laminates. D.Sc. Thesis, Technion, Israel Institute of Technology, Haifa, (in Hebrew)Google Scholar