Module Compression Pad Mechanics under Non Linear Swelling Force Profiles
Non-linear swelling forces mandate hyperelastic compression pads that hold module interfacial pressure between 0.02 MPa and 0.60 MPa over full cell life.
Mooney-Rivlin Model
Meaning
Phenomenological hyperelastic material formulation calculates stress strain behavior in incompressible elastomeric components subjected to large non-linear mechanical deformations. Applying the mooney-rivlin model enables finite element simulations to accurately predict pressure distributions and deformation profiles in battery module foam cushions. This mathematical model applies specifically to hyperelastic, non-linear isotropic materials under moderate strain regimes and excludes linear elastic structural metals.
Strain Energy
Continuum mechanics formulations use strain invariants to describe non-linear material response under mechanical load. The mooney-rivlin model defines a strain energy density function based on two material constants derived from uniaxial and equibiaxial tension tests. These coefficients govern the initial shear modulus and the non-linear hardening slope under increasing deformation.
Accurately capturing non-linear behavior allows mechanical designers to model internal foam pad response across various compression levels.
Parameter Calibration
Experimental stress-strain data collected across multiple loading modes fits material constants to real physical specimens. Calibrating a mooney-rivlin model requires physical testing of silicone or polyurethane foams in uniaxial tension and compression. Improper parameter fitting causes convergence errors or inaccurate force predictions in multi-axial structural simulations.
Validated material constants ensure finite element software correctly calculates compressive resistance under cell swelling loads.
Hyperelastic Prediction
Simulation of complex geometrical shapes under extreme mechanical displacement relies on strain energy functions to maintain numerical stability. Implementing a mooney-rivlin model within module stress models predicts non-uniform force concentration across pouch cell faces during swelling events.