The objective of this study was to propose a new analytical model for studying response of head impacts. Head is modeled by fluidfilled ellipsoidal shell of inconstant thickness impacted by a solid elastic sphere. Modeling the head as an ellipsoid is more realistic than modeling it as a sphere, the previous model existing in the literature [3]-[8]. In this model, the effect of Hertzian contact ...

The contact area and pressure distribution in a wheel/rail contact is essential information required in any fatigue or wear calculations to determine design life, re-grinding, and maintenance schedules. As wheel or rail wear or surface damage takes place the contact patch size and shape will change. This leads to a redistribution of the contact stresses. The aim of this work was to use ultrasou...

background: despite their simplicity and the low-cost, the conventional non-contact uv systems have low efficiency in water disinfection. the purpose of this study was to examine the possibility of upgrading these systems by some modifications in order to maximize the water contact with the uv radiation and as a result a better disinfection.    methods: in this study, two enhanced models of non...

Helical springs within the primary suspension are critical components for isolating the whole vehicle system from vibration generated at the wheel/rail contact. As train speeds increase, the frequency region of excitation becomes larger, and a simplified static stiffness can no longer represent the real stiffness property in a vehicle dynamic model. Coil springs in particular exhibit strong int...

Kuitunen, Sami Muscle and joint stiffness regulation during normal and fatiguing stretchshortening cycle exercise Jyväskylä: University of Jyväskylä, 2010, 76 p. (Studies in Sport, Physical Education and Health, ISSN 0356-1070; 149) ISBN 978-951-39-3969-4 (PDF), 978-951-39-3954-0 (nid.) Finnish summary Diss. The present series of studies were designed to investigate the regulation of leg stiffn...

The NNM (Nonlinear normal modes) have recently been investigated with the method of strained coordinates for spring mass models with some springs with piecewise linear stiffness. The N d.o.f. case and the mathematical validity of the method for large time were rigorously proved. The time validity is related to the nature of contact. For grazing contact, this method and also the multiscale expan...

an aircraft wing needs to display different mechanical behavior in different directions. 1- stiffness in the spanwise (transverse to the corrugation) direction which enables the aerodynamic and inertial loads to be carried. 2- compliance in the chordwise (corrugation) direction which would allow shape changes and increases in surface area; whereas a corrugated sheet due to their special geometr...