DYNAMIC LOAD 3 Dynamic load coefficient Dynamic response D ynamic load coeficient K R=K, Static response 4> Classification of the dynamic stress 1).Simple dynamic stress: The acceleration can be determined. We may apply the method of kineto static" to solve this kind of problems 2). Impact load: The velocity changes sharply in a very short time. In this case the acceleration can not be determined. We must apply the energy method to solve this kind of problems 3).Alternating stress: Stress changes periodically with time. It belongs to the fatigue problem 4). Vibration problems: There are many methods to solve this kind of problems3、Dynamic load coefficient：  d =Kd  j Static response Dynamic response Kd = 4、Classification of the dynamic stress： 1).Simple dynamic stress： The acceleration can be determined. We may apply the“method of kineto static” to solve this kind of problems. 3).Alternating stress：Stress changes periodically with time. It belongs to the fatigue problem. 4).Vibration problems：There are many methods to solve this kind of problems. Dynamic load coefficient 2).Impact load：The velocity changes sharply in a very short time. In this case the acceleration can not be determined. We must apply the “energy method” to solve this kind of problems；