The solder of Fig. 9-12 undergoes 10³ reversals at a strain of 1.3 × 10^-3. How many more cycles can the solder sustain before it fails at the larger strain of 10^-2?

Question

The solder of Fig. 9-12 undergoes [latex]10^{3}[/latex] reversals at a strain of[latex] 1.3 × 10^{-3}[/latex]. How many more cycles can the solder sustain before it fails at the larger strain of [latex]10^{-2}[/latex]?

Accepted Answer

Noting that [latex]2N_{f}[/latex] at these respective strain levels is [latex]\sim 10^{4}[/latex] and [latex]\sim 10^{2}[/latex], Eq. 9-25 yields [latex]1 = 10^{3}/10^{4}+2N_{i}/10^{2}[/latex]. Solving, [latex]2N_{i} = 90[/latex] reversals, or 45 cycles.

[latex]1=\Sigma R=\sum\limits_{i=1}^{n}\frac{2N_{i}}{2N_{f}}[/latex] (9-25)

Question 9.3: The solder of Fig. 9-12 undergoes 10³ reversals at a strain ...

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