Multiaxial Critical Plane Strain Life Analysis for Conformal Cooled Tooling
Multiaxial critical plane strain-life analysis models out-of-phase thermal and pressure fatigue on internal conformal cooling walls to prevent die failure.
Murakami Parameter
Meaning
Fatigue strength estimate based on the square root of the projected area of a small defect or inclusion in a metallic material. The murakami parameter provides a mathematical way to quantify how tiny imperfections like oxides or voids reduce the lifespan of structural components in battery housings. This calculation treats the defect as a small crack that grows under cyclic loading.
Area Calculation
Metallographic examination reveals the physical dimensions of the internal flaws. Once the size is known, the murakami parameter converts the geometric data into an equivalent stress intensity factor.
Material Selection
High purity steels and alloys are chosen for battery canisters to minimize the number of large inclusions. When the murakami parameter indicates a high risk of crack initiation, the manufacturing process must be adjusted to improve the filtration of the molten metal.
Failure Prediction
Engineering teams use these values to determine the maximum allowable stress for a component intended for long term use. By applying the murakami parameter, the design avoids the unexpected fractures that occur when small defects act as stress risers. This methodology ensures that the battery enclosure can withstand the vibration and mechanical shocks encountered during vehicle operation without compromising the vacuum seal or the structural integrity.