Combined Stiffness and Impact Properties

FIGURE 5.7 Toughness of various polymers (material number code in Table 5.5). 

PBT (Polyester, polybutylene terephthalate) PET (Polyester, polyethylene terephthalate) PBT (Glass reinforced) 

Let 5 and P be the maximum deflection and load reached. The input energy is the potential energy of the mass before deflection given by 

assume that all of the input energy goes into elastic-strain energy to deflect the beam, such that 

The dynamic load then is twice the static load and is given by 

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