A method to measure the capability of the human shock absorber system to attenuate input dynamic loading during the gait is presented. The experiments were carried out with two groups: healthy subjects and subjects with various pathological conditions. The results of the experiments show a considerable difference in the capability of each group's shock absorbers to attenuate force transmitted through the locomotor system. Comparison shows that healthy subjects definitely possess a more efficient shock-absorbing capacity than do those subjects with joint disorders. Presented results show that degenerative changes in joints reduce their shock absorbing capacity, which leads to overloading of the next shock absorber in the locomotor system. So, the development of osteoarthritis may be expected to result from overloading of a shock absorber's functional capacity.
The dynamic, thermoelastic response of cylindrical shells to suddenly applied and rotating thermal inputs is investigated. Fully coupled, dynamic, thermoelastic cylindrical shell equations are derived using Galerkin’s method. Identical results were obtained independently using a variational theorem. Analytical solutions to these equations are formulated for finite-length and infinite-length cylinders. Numerical results for the response of infinite-length cylindrical shells to suddenly applied and rotating longitudinal lines of heat flux are presented. It is shown that for many thermoelastic problems involving moving thermal inputs that the maximum ratio of dynamic to quasi-static deflection can be much greater than two, that dynamic effects can be important for all thicknesses within the realm of thin shell theory, and that semicoupled theory gives incorrect results in some cases for which a fully coupled theory is required.
The governing equations of coupled thermoelasticity are investigated with the aim of obtaining solutions by means of a perturbation series in the coupling parameter. The perturbation technique is applied to the equations and a simpler set of perturbation equations is obtained. The convergence of the series solution is established, and it is shown that the result is a form of the exact solution to the governing equation for a suitable range of values of the coupling parameter. Numerical results are obtained for a typical problem using only the first two terms of the series solution. A second perturbation technique, well suited to the thermoelasticity problem and based on the method of Krylov and Bogoliuboff, also is presented in this paper. The technique is applied to two problems and the results are compared with the exact solutions.
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