| The relationship between stress and growth is live ghost of biomechanics, functional adaptation is a universal rule of biomechanics. The study of relationship between stress and growth mainly includes two aspects: one is to investigate the adaptation procedure of bone growth and remodeling to its stress environment in order to set up a aptitude ,accurate, practical and can be quantified "model", this model can precisely express how functional adaptation form the inner tissue of bone. The other is to study the relation of stress environment and cell growth and energy as well as its mechanics-biology transduction mechanism at microcosmic point of view in order to essentially illuminate the mechanics at microcosmic point of view in order to essentially illuminate the mechanics of the connection of stress and growth. Although the biomechanics has been studied for a century time, but it has not formed a mature embranchment up to the present, It is a very difficult matter to introduce mechanical theory into organism, biological tissue and apparatus, because the main characteristic of organism is that it has "life". There is essential difference between the structure of zeotic alive tissue and nonliving engineering material. The incidence of osteoporosis is so high that the disease attracts a great deal of researcher. Researching the calculation model of osteoporosis now still very seldom seen in domestic and international. Hisiskes brings forward the small bone metabolism model in 2000, the 2001 hazelwood puts forward a new bone reconstruction model basing on disuse and damage theory. we absorb their advantage and established a osteoporosis mechanics model based on bmu with a time process. The advantage of that model can take account of influence of mechanics factor,biology factor( decrepitude, menopause, medicine). In the bone remodeling process, consider BMU with the relation that mechanics stimulus. Consider that osteoclast cause bone resorption and refilling time, reversal period, as well as importing in the bone resorption process correlative physiology constant, state variables, listing differential equation such as: niiq∑si Rl==1Φ,ddpt = Qr ×Nr?Qf×Nf,rrr TQ = A,fff TQ = A.integral equation, It is supposed that the threshold is 500 με, getting calculation model of osteoporosis, establish computer program. Finally, according to the simulation result of the part ,we can draw some conclusions as follows: 1. Under the situation of supposing MESr value and enduring the outside load that is less than MESr value, apply that model and make use of the computer simulation to get the variety of porosity at any time. This process about in three months along with increment of time slows down until porosity keep constant. 2. Take the different value of Q the process of osteoporosis will varies, but with increment of time slows down. 3. We take mechanics and biology factors into account. We get linear relationship between decrepitude and menopause:M ↑=5.3×f ↓─0.63×f ↓+0.1. Can say that this model accords with physiology process of osteoporosis, it is a foundation to study osteoporosis. At the same time we carry on the animal experiment, So that we can appraise the results of the simulation model. We developed the axially loaded system, digital oscilloscope, strain gauge system. We build the SD mice experiment model. One animals chosen at random were used for a preliminary load-strain calibration experiment. Immediately following anesthesia and sacrifice by cervical dislocation, the medial surface of the right ulna midshaft was minimally exposed in each mouse. The tibia was axially loaded using the loading system to be used for experimentation at the frequencies of 5Hz and peak loads of 1.0 N, 2.0 N, 3.0 N, 4.0 N, 5.0N . Finally, according to the experiment result, we can draw some conclusions as follows:...
|
PDF Full Text Request