This paper describes dynamic analysis using proposed fast finite element method for a shock absorbing structure including a sponge. The structure is supported by nonlinear concentrated springs. The restoring force of the spring has cubic nonlinearity and linear hysteresis damping. To calculate damping properties for the structures including elastic body and porous body, displacement vectors as ...

Utilizing optical Fiber Bragg Grating’s (FBG) characteristic of transmission optic signals in noncontact way, the measure method of the twisted, variable cross-section, variable thickness, rotating rectangular blade’s local strain has been presented. Firstly, by using the finite element method to obtain the rotating blade’s natural frequency, modal shape and strain modal shape, the mounting loc...

A vibration based damage identification algorithm is implemented to assess the damage of a thin–walled composite structure. The structure analysed is a skin with stiffeners, as frequently applied in aircraft components. Both experimental and numerical studies on a single composite skin–stiffener structure showed that the modal strain energy damage index (MSE–DI) algorithm is a suitable method f...

Cylindrical shells are used in a variety of applications. In some of these applications it is necessary to limit the vibrations of lightly-damped shells by applying a damping treatment that does not significantly increase the weight. This paper explores the use of partial coating of a cylindrical shell with a constrained viscoelastic layer for obtaining optimal damping. The placement of damping...

Sandwich structures are very attractive due to their high strength at a minimum weight, and, therefore, there has been a rapid increase in their applications. Nevertheless, these structures may present imperfect bonding or debonding between the skins and core as a result of manufacturing defects or impact loads, degrading their mechanical properties. To improve both the safety and functionality...

Modal strain energy (MSE) is a sensitive physical property that can be utilized as a damage index in structural health monitoring. Inverse problem solvingbased approaches using single-objective optimization algorithms are also a promising damage identification method. However, the research into the integration of these methods is currently limited; only partial success in the detection of struc...

In this work, dynamic mechanical properties of three high-manganese steels with TRIP/TWIP or fully TWIP characteristics are studied. High strain rate experiments in the range of true strain rates between ~500 and 1800 /s are conducted using a dynamic torsional testing setup. All the three steels show a positive strain rate sensitivity in the intermediate range of strain rates (up to 500 /s). Bu...

Life cycle monitoring of civil infrastructure such as bridges and buildings is critical to the long-term operational cost and safety of aging structures. The widespread use of Structural Health Monitoring (SHM) systems is limited due to unavailability of specialized data acquisition equipment, high cost of generic equipment, and absence of fully automatic decision support systems. The goals of ...