Investigation of Collapse Characteristics of Cylindrical Composite Panels with Large Cutouts.

摘要

In order to better understand the collapse properties of composite shells, an analysis of cylindrical panels with large cutouts (11-17% of surface area) was conducted with two finite element codes (STAGSC-1 and SHELL). These results were then compared to experimental findings. Existence of cutout, eccentricity of cutout, boundary conditions, and panel width are varied to see how each affected the collapse load. In addition, the release of residual strain due to placing the cutout within the panel was evaluated. It was found that placing a cutout in the panel and/or removing the vertical support reduced the total collapse load by at least 50%. Surface imperfections were seen to reduce the collapse load, but more importantly these imperfections accurately predicted the nonlinear response of the shell. STAGSC-1 accurately predicted the composite panels' response to axial compression. Transverse shear was seen to be important if the panels' free edges underwent 15-17 deg or more of rotation. Hence the SHELL program gave better results than STAGSC-1 for those panels that saw rotations greater than 17 deg. The residual stress test showed there was a measureable change in strain due to cutting the panel. However, the magnitude of this change is minimal when compared to the total collapse load of the shell. Theses. (jhd)