The rheologic model shown in Fig. 12.15 behaves differently at different strain rates. At high strain rates it behaves elastically (‘‘bounces’’). At moderate strain rates it behaves elasticoplastically (the dashpot does not have time to work unless the strain rate is low). And at low strain rates it behaves elasticoviscously. Experiment with Silly Putty, and notice that it shares some of the properties just described but is not exactly the same as the model drawn in Fig. 12.15. Silly Putty exhibits the following behavior: it bounces at high strain rates, stretches with slow partial recovery at moderate strain rates, and flows under gravitational force (low strain rates).

Draw a rheologic model for Silly Putty1 that satisfies all of these requirements, and indicate on your drawing which parts behave in which ways.

Transcribed Image Text:

Maxwell body (low €) 7eeeeeeeee- Elastic (high ) 7/ Elastico-plastic. (moderate €) Fig. 12.15 Rheologic model for use in Problem 12.2.