Long Term Interconnect Creep and Weld Fatigue under Cyclic Thermal Load in Heavy Formats
Thermal expansion and cell swell induce cyclic shear stresses that trigger weld fatigue and interconnect creep, requiring compliance flexure loops.
Larson Miller Parameter
Meaning
Creep resistance metrics allow engineers to predict the remaining life of components subjected to high stress and high temperature. The larson miller parameter relates time to failure with the absolute temperature through a specific material constant. This value is essential for materials used in thermal management systems.
Life Prediction
Calculating the expected duration of service involves plotting the stress levels against the calculated value of the constant. A high larson miller parameter suggests that a material can withstand extreme conditions for longer periods.
Material Constant
Laboratory testing determines the specific C value required for the equation, which typically centers around twenty for many metal alloys. Applying the larson miller parameter to new battery cooling plates requires extensive empirical data from stress rupture tests.
Extrapolation Logic
Designers use this method to estimate the performance of a part over decades based on tests that last only a few hundred hours. Because the larson miller parameter assumes a single dominant deformation mechanism, its accuracy depends on the temperature staying within a specific metallurgical range. If the temperature exceeds the phase transition point, the calculation becomes invalid and might lead to a catastrophic failure of the cooling system.
Regular validation through small scale testing helps maintain the reliability of the life cycle models used in the design phase. This mathematical approach simplifies the comparison of different materials under varying thermal loads.