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楼主 |
发表于 2006-3-16 10:44:36
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这几天在忙毕业设计的事情所以上次写的东西没写完(因为熄灯了)。
现在就把上次没写完的东西补上希望大家能用上:
1 interchangeability:during the repair and assemble period each of the component need not to be repaired and selected and can be assembled freely .after the assembling,the required per formance of the machine can be satisfied.
这就是可互换性的概念。
2 degree of freedom : the system's dof is equal to the number of independent parameters which are needed to uniquely define its position in space at any instant of time.
3 the dof of an assembly of links completely predicts its character .there are only three possibilities:
1)if the dof is positive ,it will be a mechanism and links will have reletive motion
2)if the dof is exactly zero ,it will be a structure and no motion is posible .
3)if the dof is negative ,then it will be a preloaded structure which means no motion is possible,and when assembled ,some stress will exist |
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