Impact strength factors affecting

Other environmental factors besides temperature may also affect impact behavior. For example, if the material is in the vicinity of a fluid which attacks it, then the crack-initiation energies may be reduced, resulting in lower impact strength. Some materials, particularly nylon, are significantly affected by water, as illustrated in Figure 3.40. The absorption of water produces a spectacular improvement in the impact behavior of nylon. 

The mobility classification of the equipment is another important factor affecting the products testing and construction requirements, such as impact and drop tests, leakage limits, enclosure strength, and labeling. The equipment categories are ... 

Grade X These laminates are used for mechanical applications and are affected by humidity. They are not usually used in electrical applications as an insulating material. The impact strength is low. Rolled tubes machine easily and have low dissipation factors. Rods are not available. 

The correlations that have been discussed [eqs. (2) and (4)] reflect our current views on factors affecting the sensitivities of nitroaromatics, nitranoines and nitroaliphatics. Our results suggest that the strengths of all the N-NO and C-NO2 bonds in nitramines and nitroaliphatics, respectively, t en in conjunction with the overall size of the molecule, help to determine their shock sensitivities [see eq. (4)]. Nitroaromatics, however, must be treated differently their impact sensitivities do not follow eq.(4). With the exception of hydroxynnitroaromatics, a reasonable correlation is found between Vniid,max d impact... 

Long branches affect more pronouncedly the poly-dispersity. It is generally considered that, when the other structural factors are constant, a narrower MWD leads to an increase in impact strength, tensile strength, toughness, softening point and resistance to environmental stress cracking. 

Impact strength is often a very important design requirement and is affected by three principal factors-temperature, stress concentration and materials factors. It is important to remember that a tough material may behave in a brittle manner at low temperature however, stress concentrations are the most common source of failures in practice because of the very high stresses induced at corners, holes, keyways, etc.. An example of the effect of stress... 

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