Mechanical behavior, dynamic loading

Cagnoux, J. and F. Longy (1988), Proc. DYMAT88 International Conference on Mechanical and Physical Behavior of Materials under Dynamic Loading, Les Editions de Physique, France, pp. 3-10. 

Karnes, C.H., The Plate Impact Configuration for Determining Mechanical Properties of Materials at High Strain Rates, in Mechanical Behavior of Materials Under Dynamic Loads (edited by Lindholm, U.S.), Springer-Verlag, New York, 1968, pp. 270-293. 

The behavior of materials (plastics, steels, etc.) under dynamic loads is important in certain mechanical analyses of design problems. Unfortunately, sometimes the engineering design is based on the static loading properties of the material rather than dynamic properties. Quite often this means over-design at best and incorrect design resulting... 

The behavior of materials under dynamic load is of considerable importance and interest in most mechanical analyses of design problems where these loads exist. The complex workings of the dynamic behavior problem can best be appreciated by summarizing the range of interactions of dynamic loads that exist for all the different types of materials. Dynamic loads involve the interactions of creep and relaxation loads, vibratory and transient fatigue loads, low-velocity impacts measurable sometimes in milliseconds, high-velocity impacts measurable in microseconds, and hypervelocity impacts as summarized in Fig. 2-4. 

Lindholm, U. S., Mechanical Behavior of Materials under Dynamic Loads, Springer-Verlag, 1968. 

International Conference on Mechanical Behavior of Materials under Dynamic Loading, Journal de Physique, Colloque CS, Supplement au No. 8, Tome 46 (Aout 1985). 

We first briefly review the effects of M on physical properties under monotonic loading conditions. Some properties, such as density and low temperature dynamic mechanical behavior, are essentially unaffected by changes in molecular weight. Other properties, such as the glass transition temperature, T, and the tensile strength, increase appreciably with M in the low molecular weight region but tend to approach an asymptotic value as M is further increased. Fox and Flory have shown that for PS the dependence of T on M can be expressed as... 

We have already referred to various kinds of data on mechanical behavior of polymers. We are now going to consider methods of acquisition of such information. The most fi equently used are the so-called quasistatic methods which involve relatively slow loading. Tension, compression, and flexure belong here. The quasistatic methods have to be distinguished from so-called transient tests which include stress relaxation and creep. There are also impact tests and dynamic mechanical procedures which will be defined later. 

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