Fatigue Strength Analysis And Dynamic Load Test Of Reciprocating Pump Crankshaft

Crankshaft is one of the most important and expensive parts in reciprocating pump, and also is the part with the most complex boundary conditions. Its structural strength determines the bearing capacity and working reliability of reciprocating pump. Fatigue fracture of the crankshaft may cause damage to other parts of reciprocating pump. With the development of high speed, high strength of pump, the work condition of the crankshaft will become more challenging. So the strength analysis of the crankshaft is of great importance at the process of the design and improvement of pump.This paper takes a type of single-acting reciprocating triplex pump crankshaft as the study object, research on the crankshaft was conducted with the method of simple beam analytical method, program technical of computer, finite element simulation. At the same time, the experimental measurement was done on the pump whose flow rate can be adjusted. Discuss the necessarity of strength calculation based on the actual dynamic load. The main contents are as follow:1) Mechanical analysis of crankshaft based on the method of simple beam analytical method, the formulas of inner, outside force and section stress, coming from working process, were given. Based on Visual Basic6.0, the reciprocating pump crankshaft strength check system was developed..2) 3-D solid modal of crankshaft was developed by Solidworks, and imported into Ansys for meshing. Four dangerous cases under two different boundary conditions were analyzed based on FEM, and stress distribution of crankshaft was obtained. Then fatigue strength check was done based on finite element analysis result. The reliability of fatigue strength check system is validated through the finite element analysis result and provides an important reference to the crankshaft design and improvement.3) Using the method of dynamic strain measurement, the dynamic load of reciprocating pump was studied. Variation of dynamic load with flow turndown ratio, stroke speed and pressure were obtained through analysis. Based on actual dynamic load, fatigue strength check was conducted. Then the necessarity of strength calculation based on the actual dynamic load is discussed.The research result shows, the method combine fatigue strength check system and finite element analysis can greatly improve the computational efficiency without losing calculation accuracy. Variation of pump dynamic load was obtained through dynamic strain measurement. Analysis result show the fatigue strength check of flow adjustable pump must based on the actual dynamic load calculation.