Failure Theories
Failure theories are essential in predicting whether materials or structures will fail under various loads. This chapter covers static failure theories, such as maximum normal stress and shear stress theories, as well as fatigue failure theories that address cyclic stress applications. It emphasizes the importance of effectively applying a factor of safety and understanding stress concentration factors in design processes.
Sections
Navigate through the learning materials and practice exercises.
What we have learnt
- Failure occurs when materials experience excessive deformation, fracture, or fatigue.
- Static failure theories help assess the safety of components under constant loads.
- Fatigue theories highlight that materials can fail over time with cyclic or fluctuating stresses.
Key Concepts
- -- Maximum Normal Stress Theory
- Predicts failure in brittle materials when the maximum principal stress exceeds the yield stress.
- -- Maximum Shear Stress Theory
- States failure occurs when the maximum shear stress is equal to or exceeds the shear yield strength, applicable for ductile materials.
- -- von Mises Stress
- A derived scalar stress used for assessing ductile material failure compared to the yield strength.
- -- Stress Concentration Factors
- A measure of localized increase in stress at points of discontinuity due to geometric features like notches or holes.
- -- Endurance Limit
- The maximum stress level that can be applied for an infinite number of cycles without causing fatigue failure.
Additional Learning Materials
Supplementary resources to enhance your learning experience.