Effect of whole-body vibration on human body while crossing speed hump

In medical point of view study of whole-body vibration is very important because whole-body\ud vibrations (WBV) has adverse e ects on ride comfort and human health. Major back pain problems\ud arises due to long term exposure to vibration, also it can induce degenerate changes in lumber spine.\ud ISO 2631-5:2004 is used to evaluate the e ect of long-term exposure to the WBV on human health.\ud It de nes a method of quantifying whole-body vibration containing multiple shocks (such as bumpy\ud rides) in relation to human health. It uses peak vibration (shock) values to predict compression\ud stress in the spine, and reports equivalent daily static compression dose,\ud S\ud ed\ud . The results show\ud high\ud S\ud ed\ud values with high health risks even at low speeds. Therefore to invistigate the e ect of\ud whole body vibration on human body a two dimentional combined multibody model of half car\ud and human body is build which allows the determination of joint reaction forces at each body joint\ud and adverse e ect of whole body vibration on human spine. Half car model consist of sprung mass,\ud unsprung mass and spring-damper(suspension). Half car model has four degrees of freedom. Human\ud hody model consists of rigid bodies which represent major human body segments and structured as\ud linked open-tree multibody system. For vertical excitation speed hump of various pro les are used.\ud Various models of human body and half car are used to study the e ect of WBV on human body.\ud The intensity of WBV is reduced by seat inclination