Predictive Cavity Surface Degradation Modeling under Thermal Shock and Acidic Resin Outgassing
Coupling transient thermal strain models with Arrhenius acid dissolution rates predicts cavity pitting and fixes tooling refurbishment intervals.
Coffin-Manson Fatigue
Meaning
Mechanical life estimation standards evaluate low-cycle plastic deformation limits in structural components subjected to repeated thermal cycling. Damage accumulation predicted by coffin-manson fatigue models correlates plastic strain range with cycles to failure in battery busbars and interconnects. The empirical relationship focuses on low-cycle failure regimes where cyclic plastic strain dominates elastic deformation.
The formulation governs strain-life fatigue limits and joint endurance bounds in welded electrical connections.
Plastic Strain
Repeated mechanical loading past the yield point causes irreversible crystal lattice slip. Coffin-manson fatigue laws model this plastic strain amplitude as an inverse power function of operational life cycles.
Thermal Cycling
Temperature swings generate differential thermal expansion between dissimilar pack materials. Busbar joints absorb mechanical displacement as battery modules heat during rapid discharge and cool during rest. Cyclic strain accumulates at laser weld interfaces, initiating micro-cracks that propagate through the joint cross section.
Higher plastic strain ranges shorten structural life exponentially.
Interconnect Failure
Joint degradation increases electrical resistance across high-current paths in cell packs. Resistance spikes accelerate localized heat generation, triggering thermal failure modes in adjacent module components. Engineering specifications define allowable thermal expansion limits based on low-cycle strain calculations.
Coffin-manson fatigue equations determine warranty life bounds for battery pack electrical busbars.