刚体的虚功原理:在力的作用下处于____状态的体系中,当发生与约束条件相符合的任意微小的刚体位移时,体系上所有的_______在位移上所作的总功恒等于零。
查看答案
弹性力学的研究任务是研究弹性体由于受外力作用或由于温度改变等原因而发生的应力,形变和位移。
A. 对
B. 错
形函数的性质中,在单元任一点上,三个形函数之和不等于1
A. 对
B. 错
Ithasbeenreplacedbydeadboltlocks,securitychains, (1)alarmsystemsandtripwires (2) a policestationorprivateguardfirm.Many (3) families haveslidingglassdoorsontheirpatios,withsteelbarselegantly (4) sonoonecanprythedoorsopen. Itisnot (5) ,inthemostpleasantofhomes,toseepastedonthewindowssmallnotices(6) thatthepremisesareunder(7)bythissecurityforceorthatguard company.Thelockisthenew(8) ofAmerica.Indeed,a recentpublic-serviceadvertisementbyalargeinsurancecompany (9) notchartsshowinghowmuchatriskwe are,buta pictureofachild'sbicyclewiththenow-usualpadlock (10) it.