Chapter 10: Dynamic Loads¶
10.1 Introduction¶
The loads change sharply with time, and the velocity of the member changes obviously (there exists inertia force in the member).
Experiments proved that Hooke's law applied validly under static loads can be applied to the cases under dynamic loads.
- Dynamic load coefficient
\[ K_d = \frac{\text{Dynamic response}}{\text{Static response}} = \frac{\sigma_d}{\sigma_{st}} \]
Classification of dynamic loads:
- Simple dynamic stress: the acceleration can be determined: “method of kinetostatic（动静法）”
- Impact load
- Alternating load
- Vibration
10.2 Method of Kineto-Statics¶
- D'Alembert's principle
- Primary force system + Inertia force system = Equilibrium force system
10.4 Stresses & Deformations Under Impact Loads¶
能量守恒 \(T + V = V_{\varepsilon d}\)