Inclusion of transverse shear deformation in the exact buckling and vibration analysis of composite plate assemblies

The problem considered is the development of the necessary plate stiffnesses for use in the general purpose program VICONOPT for buckling and vibration of composite plate assemblies. The required stiffnesses include the effects of transverse shear deformation and are for sinusoidal response along the plate length as required in VICONOPT. The method is based on the exact solution of the plate differential equations for a composite laminate having fully populated A, B, and D stiffness matrices which leads to an ordinary differential equation of tenth order

Exact methods for modal transient response analysis including feedback control

This paper presents a modal method for the analysis of controlled structural systems that retains the uncoupled nature of the classical transient response analysis of a structure subjected to a prescribed time-varying load. The control force is expanded as a Taylor series that remains on the right side of the equations, and it does not lead to a computational approach that requires coupling between modes on the left side. Retaining a sufficient number of terms in the series produces a solution to the modal equations that is accurate to machine precision. The approach is particularly attractive for large problems in which standard matrix exponential methods become computationally prohibitive. Numerical results are presented to show the accuracy and efficiency of the proposed approach for dynamic feedback compensation of a truss structure with local member modes in the controller bandwidth

Axisymmetric shell analysis of the space shuttle solid rocket booster field joint

The Space Shuttle Challenger (STS 51-L) accident led to an intense investigation of the structural behavior of the solid rocket booster (SRB) tang and clevis field joints. Results are presented of axisymmetric shell analyses that parametrically assess the structural behavior of SRB field joints subjected to quasi-steady-state internal pressure loading for both the original joint flown on mission STS 51-L and the redesigned joint flown for the first time after the STS 51-L accident on the Space Shuttle Discovery. Discussion of axisymmetric shell modeling issues and details is presented and a generic method for simulating contact between adjacent shells of revolution is described. Results are presented that identify the performance trends of the joints for a wide range of joint parameters. An important finding is that the redesigned joint exhibits significantly smaller O-ring gap changes and much less sensitivity to joint clearances than the original joint. For a wide range of joint parameters, the result presented indicate that the redesigned joint provides a much better pressure seal than the original joint

Experimental Observations of Aerodynamic and Heating Test on Insulating Heat Shields

Several different types of insulating heat shields have been subjected to aerodynamic tests and radiant-heating tests in order to obtain a better insight into the problems involved when the primary structure of m aerodynamically heated vehicle is substantially cooler than the exposed external surface. One of the main problems was considered to be a proper allowance for thermal expansion caused by these large temperature differences, so that undue distortion or thermal stresses would not occur in either the outer shield or the underlying structure. corrugated outer skin with suitably designed expansion joints was a feature of all the specimens tested

A Tension Shell Structure for Application to Entry Vehicles

The shape of a shell of revolution designed t o have only tensile stresses under axisymmetric aerodynamic loadings has been derived on the basis of linear membrane theory. values of circumferential tension is also given. The results of this paper indicate that the design of an entry vehicle based on the tension shell concept leads to desirable aerodynamic and structural characteristics, namely, high drag and low weight