Interfacial Contact Resistance Calibration in Heterogeneous Tooling Expansion Analysis
Calibrating interfacial contact resistance prevents thermal expansion model error and locates joint distortion before tool manufacturing commitments proceed.
Micro-Contact Pressure
Meaning
Localized contact stress generated across microscopic surface peaks converts macroscopic compressive loads into high physical stress points. In precision sealing and electrical connector manufacturing, micro-contact pressure determines local plastic deformation of surface asperities and true contact area. The parameter governs fluid leakage thresholds across metal-to-metal seals and electrical contact resistance across plated terminals.
It stops applying when bulk plastic yield flattens all surface roughness into full solid contact.
Asperity Flattening
High peak stresses induce localized plastic flow even when global assembly loads remain well within elastic limits. As asperities flatten, actual contact area increases, reducing local stress and establishing stable electrical conduction paths. Relying on average nominal joint pressure calculations conceals localized stress peaks that crack thin protective gold plating during terminal crimping.
Local Stress
Peak stresses at roughness tips exceed yield strength long before global material yielding occurs.
Seal Integrity
Quality control runs evaluate joint sealing performance by conducting helium leak audits on flange assemblies under nominal bolt loads. Early signoff based on smooth lab specimens masks high leakage rates on production cast housings where higher surface roughness lowers effective micro-contact pressure. Advanced profilometry and contact mechanics FEA predict micro-contact pressure profiles before finalizing gasket specifications.
Maintaining peak contact stress above fluid pressure limits prevents slow leakage across metal seal interfaces.