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$17\mathrm{.}1$ The copper water$-$cooling plates in the Worked Example failed at welded joints which connected the plates to the inlet and outlet water pipes. During thermal cycling of the furnace, the pipes were bent back and forth, which resulted in cyclic straining of the welds. The strain amplitude was estimated to have been $0\mathrm{.}01.$ Using the strain$-$life plot in the diagram, estimate the number of cycles required to cause the welded joints to fail. Your estimate of the strain amplitude could be in error by a factor of $2.$ What would be the failure life if the strain amplitude were as large as $0\mathrm{.}02?$