Improving the fatigue life of thin plates with small-spacing adjacent double holes with electromagnetic process

Abstract

The fatigue life of thin plates with small-spacing adjacent double holes processed using the electromagnetic cold expansion method was investigated with employing both numerical and experimental approaches. The results indicated that radial tensile stress is generated during electromagnetic processing, effectively preventing warping during the strengthening of thin plates. Importantly, uniformly distributed tangential compressive residual stress along the thickness direction near the holes was produced after the electromagnetic method. This distribution effectively mitigates the accumulation of crack sources in areas of low residual compressive stress under fatigue load. Furthermore, the depth of the compressive stress area in the radial direction was found to be 4–5 times greater than that achieved by conventional cold expansion methods. Fatigue testing further demonstrated the superior performance of the electromagnetic method, revealing a more than tenfold increase in fatigue life under an external load of σ_max = 100 MPa.