Goodman Diagram
The Goodman diagram shows the allowable stress amplitudes for different mean stresses. It helps in the safe design of components under fatigue loading.
Physical-Chemical Mechanism of Action
The Goodman diagram is a graphical tool that visualizes the fatigue life of components under cyclic loading. It is based on the assumption of linear material behavior and shows the allowable stress amplitude for given mean stresses.
Metallurgical Relevance & Risks in Welding
Failure to properly consider the Goodman diagram can lead to premature failure of components under fatigue. This results in cracks and fracture, endangering the safety of the system. An incorrect diagram can also lead to overstressed components that yield or fail suddenly.
Workshop Practice & Action Instructions
To correctly apply the Goodman diagram:
1. Determine the actual stress cycles in the system.
2. Read the allowable operating point from the diagram by plotting the mean stress on the x-axis and the stress amplitude on the y-axis.
3. Compare this point with the actual operating point. If it lies below the allowable region, the material is safe. Otherwise, take measures to reduce stress or strengthen the component.