Quantifying Time Dependent Viscoelastic Deformation during Coordinate Metrology Audits
Unmanaged viscoelastic creep under metrology clamping fixtures consumes up to forty percent of engineering tolerances, requiring documented dwell periods.
Generalized Maxwell Model
Meaning
Viscoelastic constitutive framework consisting of multiple Maxwell elements arranged in parallel with an optional spring. Each element represents a specific relaxation time for the material, allowing for a broad spectrum of time-dependent responses. Use of the generalized maxwell model provides a more accurate representation of complex polymers than a single spring and dashpot assembly.
Time Dependency
Stress in the material dissipates at various rates depending on the molecular weight distribution. Because the generalized maxwell model incorporates several branches, it captures the behavior of the material across many decades of time. This allows for precise simulations of long-term creep and rapid impact.
Numerical Implementation
Computational tools solve the differential equations to predict part performance under varying loads. The generalized maxwell model relies on a Prony series to fit experimental data from stress relaxation tests.
Capability Verification
Accurate modeling prevents the premature failure of elastomeric components in high-stress environments. Since the generalized maxwell model reflects the internal damping of the material, it is used to certify parts for aerospace and automotive applications. Failing to account for all relaxation modes leads to unexpected dimensional changes.
The cost of a late-stage redesign is avoided by verifying the model against physical pilot results during the early development phase.