Clasen, Michael Dominik

A cooperation project with the Bundeswehr Technical Center for Weapons and Ammunition (WTD-91) is about the acoustic camouflage of military vehicles. Thus, the properties of active and passive damping materials are investigated. Passive acoustic metamaterials (PAMM) have the possibility to create stop bands of sound transmission within determined frequency ranges. In this contribution, PAMM with face centered cubic (FCC) lattice structure are realized by Computer Aided Design (CAD) and investigated simulatively by the Finite Element Method (FEM).

Shockmounts in naval applications are used to mount technical equipment onto the structure of naval vessels. The insulating effect against mechanical shock is important here, as it can excite the structure in the event of underwater explosions and otherwise cause damage to the equipment. Although knowledge of the dynamic properties of shockmounts is important to naval architects, the dynamic force-displacement characteristics of shockmounts are often tested and measured statically and/or in the harmonic field. Recently, an inertia-based method and a dynamic model for measuring the dynamic force-displacement characteristics of shockmounts was described. This paper presents a full description of a testbench for implementing this method. The testbench incorporates a drop table for excitation. The proposed setup can be configured for measuring the dynamic characteristics of elastomer and wire rope shockmounts, with shock loads in compression, tension, shear and roll directions. The advanced Kelvin–Voigt model for shockmounts is applied, showing that the dynamic force-displacement characteristics measured with this setup are qualified to generate model parameters for further use.

In the marine environment, naval vessels are often influenced by underwater compression waves. Transport and dangerous goods require advanced protection beyond linear, static considerations. Therefore with regard to shock influence, the dynamic characteristics of helical wire-cable-isolators are investigated. The shock impact is given by basepoint acceleration measurement data exciting a mechanical model observing nonlinear stiffness as well as hysteretic damping effects. Three simulation models are presented here: the advanced Kelvin-Voigt model, the join patch model and the modified Bouc-Wen-Model. A comparison between simulation and measurement results is given.