周期性不平衡 meaning in English

cyclical disequilibrium
cyclical disequillibrium

It is applied to sorts of locomotive engine , in course of revolving of crank and connecting rod mechanism , there are revolving of the crankshaft , swinging of the connecting rod and reciprocating motion , so its motion state is complex , and periodic unbalanced force , by a few components , is great
曲柄连杆机构在高速运转过程中，有曲轴的转动、连杆的摆动及活塞的往复运动，其运动状态复杂，各个部件所产生的周期性不平衡惯性力大，是引起发动机振动的主要原因。