Load spectrum simplification method for aircraft construction crack extension test

Abstract

The invention discloses a load spectrum simplification method for an aircraft construction crack extension test. The load spectrum simplification method comprises the following steps: (1) determining the structural type of a crack extension test piece and a material containing a crack part, and determining the fatigue crack extension threshold value deltaKth of the material; (2) determining a stress intensity factor of a crack tip of the material; (3) estimating the crack length in the crack extension test and processing in a segmenting manner; (4) deleting the stress cycle lower than the fatigue crack extension threshold value in a load spectrum according to the segmentation condition to form a load spectrum corresponding to the lengths of the segments of the crack, and finally applying the load spectrum in the crack extension test. The load spectrum simplification method disclosed by the invention is used for determining the cark tip stress intensity factor value of a crack-containing structure and simplifying the load spectrum for the crack extension test in the segmenting manner in combination with the fatigue crack extension threshold value deltaKth of the material, so that the load spectrum can be directly applied in the aircraft construction crack extension test, and the method is simple and feasible and is capable of effectively shortening the test period.

Description

technical field [0001] The invention belongs to the aircraft load spectrum loading technology, and relates to a load spectrum simplification method for the crack growth test of an aircraft structure. Background technique [0002] With the vigorous development of the domestic aviation industry, more and more civilian / military aircraft need to undergo fatigue / crack growth tests, and the test cycle is generally relatively long, which seriously restricts the development time of the aircraft, and is also a waste of manpower and financial resources. [0003] For a long time, the idea of ​​shortening the test period by simplifying the load spectrum has been continued. On this basis, low-load interception, high-load interception technology, and simplified constant-amplitude spectrum have been formed. Among them, the idea of ​​low-load cut-off technology is to cut off the load levels in the load spectrum that do not contribute to crack growth, thereby reducing the number of load leve...

AI Technical Summary

Problems solved by technology

However, in the prior art aviation fatigue / crack growth test, due to the complexity of the crack growth of aviation metal materials, the fatigue test cycle is generally relatively long, which seriously restricts the development time of the aircraft and increases the development cost

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