Rankine's failure theory, also known as the maximum-normal stress theory, predicts that a material will fail when the maximum principal stress reaches a critical value. This critical value is equal to the tensile strength of the material. In simpler terms, it assumes that a material will break when the maximum stress acting on it exceeds the material's ability to withstand that stress.
This theory is commonly used for brittle materials, which are known to fail suddenly under high stress.
Examples of applications:
- Earth pressure: Rankine's theory is used to calculate the lateral pressure exerted by soil on retaining walls.
- Pressure vessels: The theory can be used to determine the maximum pressure that a vessel can withstand before failure.
- Brittle materials: Rankine's theory is a simple and effective way to predict failure in brittle materials like concrete and glass.
Key points to remember:
- Rankine's theory assumes that failure occurs due to tensile stress.
- It is a relatively simple and conservative theory.
- It is not suitable for ductile materials, which exhibit significant deformation before failure.
