Meaning
Mathematical constitutive model used to predict long-term creep deformation in polymer matrix composites and structural plastics subjected to continuous mechanical stress. Material engineers use the Findley Power Law to extrapolate short-term laboratory creep test data into multi-year strain predictions for load-bearing commercial components. Component manufacturers incorporate these power-law calculations into product warranties and technical datasheets to define maximum allowable structural loads for distributed polymer products.
Inaccurate creep predictions lead to premature structural distortion, invalidating vendor performance claims and creating commercial warranty liabilities.
Deformation Model Formulation
Stress analysis models compute total time-dependent strain by combining initial elastic strain with time-dependent power-law creep strain components. Test laboratories determine material-specific stress coefficients and time exponents through accelerated stress testing under controlled environmental conditions. Design engineers use calculated parameters to establish safe component working stress limits.
Contractual Performance Claim
Component supply contracts specify maximum allowable creep strain values derived from validated power-law parameters. Material suppliers guarantee that delivered composite batches conform to baseline stress-strain response curves established during product qualification. Substandard material lots triggering excess creep deformation require vendor replacement under commercial warranty terms.
Stress Level Limit
Power-law equations maintain accurate creep predictions only within linear viscoelastic stress limits. Applying excessive structural loads causes non-linear plastic deformation that invalidates empirical model predictions. Operating components beyond linear stress thresholds voids manufacturer performance guarantees.
