Fatigue test method of cylinder cover simulating test specimen

Abstract

The invention provides a fatigue test method of an engine cylinder cover simulating test specimen. The fatigue test method comprises the following steps: through a finite element simulation method, computing three principal stress-strain values at different dangerous positions of an entity cylinder cover; establishing a test specimen model; setting the maximum cyclic load value required to be exerted to a unidirectional tension and compression test bench; computing three principal stress-strain values at dangerous positions of the test specimen model; comparing the three principal stress-strain values at the dangerous positions of the test specimen model with those of the entity cylinder cover respectively to determine the final test specimen model; machining and shaping the determined final test specimen model, and then performing fatigue test on the unidirectional tension and compression test bench. According to the fatigue test method, purely mechanical fatigue test replaces thermal-mechanical coupling fatigue test, so that the test period can be greatly reduced, and the test accuracy is ensured to a certain extent.

Description

technical field [0001] The invention relates to a fatigue test method of a cylinder head simulation part, which belongs to the technical field of fatigue test. Background technique [0002] As one of the most important parts of the engine, the working environment of the cylinder head is very harsh, and the stress on the cylinder head is very complicated. On the one hand, the bolt pretightening force generated during the assembly process, the valve seat ring interference force and the residual stress generated during the casting process will act on the cylinder head throughout the working process. On the other hand, due to the influence of the engine start-stop working conditions or the idling-full load working conditions, etc., the cylinder head will bear the alternating heat load of the cycle. In addition, the high-frequency burst pressure generated in the cylinder will also Acts on the fire side of the cylinder head. [0003] The structure of the cylinder head is very co...

AI Technical Summary

Problems solved by technology

Due to the complexity of the structure and working conditions of the cylinder head, its main dangerous position is often under the state of multiaxial stress, and it is prone to fatigue damage under the condition of thermal-mechanical coupling

[0004] In recent years, researchers have conducted a large number of studies based on experiments and simulations on multiaxial fatigue problems. However, the research objects are mostly limited to standard parts.

The main reasons are: the thermal-mechanical coupling fatigue test for the solid cylinder head has high requirements for experimental equipment and a long test period, and the specific implementation process is very difficult and complicated

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