Bystander said:Have you done any searches? Give people some idea what level to talk/write to? https://www.google.com/search?rlz=1C1CHFX_enUS577US577&ei=vl4cWqjHGMrMjwPLw7uQCQ&q="strain+rate"+"brittle+fracture"&oq="strain+rate"+"brittle+fracture"&gs_l=psy-ab.12..0i30k1.52152.62972.0.67204.9.9.0.0.0.0.79.659.9.9.0...0...1c.1.64.psy-ab..0.9.658...0i8i30k1j0i7i30k1j0i8i7i30k1.0.jqXnWuAfbsg
Do you have some specific examples of materials?cuigm371 said:Why are materials whose yield stresses are highly strain-rate dependent
more susceptible to brittle fracture than those materials whose yield stresses do not exhibit marked strain-rate dependence
cuigm371 said:Fracture and Failure Analysis and this is one of the past questions that I have seen.
But it is important to know why that is.With a very high rate of application of stress there may be insufficient time for plastic deformation of a material to occur under normal conditions, a ductile material will behave in a brittle manner.
Strain-rate dependent materials have a tendency to fail more easily under high strain rates because their microstructure is not able to adjust quickly enough to the applied stress. This can lead to the formation of microcracks and ultimately, brittle fracture.
The higher the strain rate, the more likely it is for brittle fracture to occur in strain-rate dependent materials. This is because the faster the material is deformed, the less time it has to undergo plastic deformation and redistribute stress, making it more prone to failure.
Yes, materials with a high strength-to-weight ratio, such as ceramics and composites, are more prone to brittle fracture under high strain rates due to their inherently brittle nature. Additionally, materials with a high strain-rate sensitivity, such as some polymers and metals, are also more likely to experience brittle fracture.
The microstructure of a material plays a crucial role in determining its susceptibility to brittle fracture under high strain rates. Materials with a fine grain size are more susceptible due to the presence of grain boundaries, which act as stress concentrators and can facilitate the formation of cracks. Similarly, materials with a high degree of anisotropy, such as fiber-reinforced composites, can also be more prone to brittle fracture under high strain rates.
Yes, the likelihood of brittle fracture in these materials can be reduced by adjusting the strain rate, temperature, and microstructure. Lowering the strain rate and decreasing the temperature can allow for more time for plastic deformation and stress redistribution, making the material less prone to brittle fracture. Additionally, controlling the microstructure, such as through grain refinement or orientation, can also improve the material's resistance to brittle fracture under high strain rates.