Connotation and measurement of the uncertainty of radial runout of remanufactured crankshaft

Abstract

The uncertainty of radial runout of remanufactured crankshaft is a key factor affecting the quality and the safety of the remanufactured engine. First, the connotation of radial runout's uncertainty of the remanufactured crankshaft journal is analyzed, based on the failure mode of the recycled scrap crankshafts and the diversity of the uncertainty of radial runout which is caused by different remanufacturing repair technology. The uncertainty of the radial runout is classified into random uncertainty and fuzzy uncertainty based on the reasons of the uncertainty of radial runout. Then, "random entropy" is used to measure the random uncertainty and "fuzzy entropy" is applied to measure the fuzzy uncertainty of radial runout respectively. A composite entropy model based on product space P×M is built to quantitatively describe the overall uncertainty of radial runout of crankshaft. Last, the verification of the measure methods is carried out with the WD615 series 68 crankshaft remanufacturing of a heavy duty engine remanufacturing enterprise as example, it is shown that the methods are effective and feasible. This research provides a theoretical basis for the decision-making of remanufacturing uncertainty optimization.