Nonlinear Creep Damage Parameter Extraction for AA3003 Coolant Plate Joints
Extracting AA3003 braze joint creep damage parameters requires DIC strain mapping under multiaxial stress to prevent premature cold plate fluid leakage.
Shear Stress Relaxation
Meaning
Mechanical stress within battery binders and seals tends to diminish over time when the material is held in a strained state. This shear stress relaxation is particularly relevant for the polymers and gaskets that are subject to vibration and expansion. It affects the structural integrity and leak proof nature of the assembly.
Material Behavior
Polymeric chains within the battery binder gradually rearrange to accommodate the forces applied during assembly or operation. Frequent shear stress relaxation can lead to a loss of contact between the active material and the current collector. This separation increases the internal resistance and reduces the total capacity of the cell.
Integrity Maintenance
Seals and gaskets must maintain a minimum level of pressure to prevent the ingress of moisture and the escape of electrolyte. Designers account for shear stress relaxation by selecting materials with low creep rates and high elastic recovery. Proper material selection ensures that the pack remains airtight over its entire service life.
Mechanical Testing
Engineers perform long term compression tests to measure the rate at which the resistive force of a component declines. Understanding shear stress relaxation allows for more accurate predictions of how the pack will respond to the mechanical rigors of transport. Data gained from these tests informs the torque specifications for bolts and the thickness of protective foams used in the final assembly.