Coefficient Ratio Exceeds 1.0e8 - Check Results Site

“Coefficient ratio exceeds 1.0e8 – Check results carefully”?

: If using contact pairs, a high "Normal Stiffness Factor" can cause high coefficients. Lowering this factor (e.g., to ) can improve convergence and conditioning. coefficient ratio exceeds 1.0e8 - check results

An inflated coefficient ratio rarely stems from a solver bug; it is typically triggered by modeling inconsistencies. 1. Mixed Unit Systems and Scale Mismatches “Coefficient ratio exceeds 1

An engineer models a heat sink with a thermal interface material (TIM) of conductivity 0.5 W/(m·K) and a copper base of 380 W/(m·K) . The coefficient ratio is 760 , well below 1e8 . However, they also model a 1-micron air gap ( k=0.026 ) as a solid layer. The ratio becomes 380 / 0.026 ≈ 14615 . Still safe. But if a single mesh cell is highly skewed at the gap interface, that local coefficient drops to 1e-6 due to geometric scaling. Total ratio: 380 / 1e-6 = 3.8e8 . An inflated coefficient ratio rarely stems from a