Table 2: The numerical example that follows is carried out with the following input data.
| Structural Element | Package | PCB | Solder (96.5% Ag 3.5% Sn) |
| Element's Number | 1 | 2 | 0 |
| Effective Young's Modulus, E, kg/mm2 | 8775.5 | 2321.4 | 1939.0 |
| Poisson's Ratio, v | 0.30 | 0.30 | 0.30 |
| Shear Modulus, G, kg/mm2 | 3367.3 | 892.7 | 1958.8 |
| CTE, 1/℃ | 6.5 × 10-6 | 15.0 × 10-6 | xxxx |
| Thickness, mm | 2.0 | 1.5 | 0.2 |
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Estimated yield stress of the solder material in shear: τY = 1.825 kg/mm2 Soldering Temperature: 158 ℃ = 431 °K Testing Temperatures: T1 = -20 ℃ = 253 °K, T2 = -100 ℃ = 173 °K Changes in Temperature: Δt1 = 178 ℃ = 178 °K, Δt2 = 258 ℃ = 258 °K The "external" thermal strains: ε1 = ΔαΔt1 = 151.3 × 10-5, ε2 = ΔαΔt2 = 219.3 × 10-5 Half Package Length l = 15 mm; Electrical Resistance Threshold at Solder Failure [51]: R* = 450 Ω |
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