Material Properties and Behavior in Mechanical Engineering

• Strength is a measure of a material's ability to withstand stress, with two key values being ultimate strength (maximum stress during a tensile test) and yield strength (stress at which material begins to deform plastically).
• Yield strength is commonly used in engineering design codes to define failure, and can be determined using the 0.2% offset method for materials with unclear transitions from elastic to plastic deformation.
• Ductility measures a material's ability to deform plastically before fracture, with ductile materials like mild steel and gold undergoing large plastic deformation, while brittle materials like glass and ceramics fracture at low strains without plastic deformation.
• Brittle materials are stronger in compression than in tension due to factors such as crack formation and lack of plastic deformation to redistribute stresses, leading to stress concentrations at crack tips.
• Ductility can be temperature-dependent, with materials like steel transitioning from ductile to brittle behavior at certain temperatures, impacting their failure mode preference.
• Toughness is the ability of a material to absorb energy up to fracture, calculated as the area under the stress-strain curve, with materials having high toughness needing a balance of ductility and strength.
• Resilience, related to toughness, is a material's ability to absorb energy when deforming elastically, important for applications where plastic deformation should be avoided.

Explore key concepts like strength, yield strength, ductility, brittleness, toughness, and resilience in materials science and mechanical engineering. Learn about how different materials behave under stress and deformation.