The Dynamic Response of SDOF Systems Loaded by a Shock Wave
2007
VAN Erkel, A. C.
To perform a quick analysis or a parameter study of structures under dynamic loads, the structure is often regarded as a Single Degree of Freedom (SDOF) system with one characteristic deflection. At the TNO Prins Maurits Laboratory these systems are used as tools for the vulnerability analysis of the structures of weapon platforms under explosion loads. For naval ships, SDOF techniques are applied for the internal blast code DAMINEX, for the external blast algorithm CBD, for ship door research and for the research of underwater shock on the hull. Therefore research is done on SDOF systems, particularly for the response of stiffened panels under large deflections introducing non linear mechanisms. This report gathers and explains some general techniques of structural dynamics for SDOF systems and serves as a basis for the application of the SDOF technique in vulnerability research. Analytical formulae for the maximum dynamic deflection have been determined, where the deflections are expressed in general terms for force, mass and stiffness. A general expression for the Dynamic Load Factor (DLF) is established for linear and non-linear deformation characteristics. Convenient mathematical approximations have been found for the response curves. New transformations factors have been derived. The curve for iso-damage based on the Pressure-Impulse technique is considered as a tool for the scope beyond the DLF. Parameter studies can be easily performed with the obtained results.
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