Testing method for design allowable value of composite material opening pore compressive strength

Abstract

The invention discloses a testing method for a design allowable value of a composite material opening pore comprehensive strength. The testing method for the design allowable value of the composite material opening pore comprehensive strength comprises the steps of 1, obtaining basic values of impact factors of technology batch, hygrothermal environment, thickness, diameter of opening pore, ratio of breadth to diameter, pore countersunk head and the opening pore compressive strength of the composite material through a cordwood system testing component and testing stage; 2, obtaining the design allowable value of the composite material opening pore comprehensive strength through a formula and the obtained data in the step 1. The adoption of the testing method for the design allowable value of the composite material opening pore comprehensive strength can solve problems in engineering practices that the obtained design allowable value of the composite material opening pore comprehensive strength through a traditional testing method has a large deviation, the quantity of testing articles is large, the cycle of testing is long, and the testing result is influenced greatly by constraint conditions such as size effect, boundary conditions and load distribution.

Description

technical field [0001] The invention relates to the technical field of aircraft composite material structure testing, in particular to a method for testing the allowable value of composite material opening compression strength design. Background technique [0002] Most of the existing test methods for obtaining the design allowable value of the compressive strength of open-cell composite materials adopt the blanket curve method (AML method). Layer percentage number is not less than 10%. [0003] The AML method is applied to symmetrical and balanced laminates, the laminates include 0°, 90° and ±45° angle layers, and the percentage of each angle layer is not less than 10%. AML was derived as the percentage of angular laminae (±45°) minus the longitudinal fibrous laminae (0°). When the laminate is unbalanced, AML is expressed by the following formula: [0004] [0005] So a laminate with a low percentage of angled plies or a high percentage of longitudinal plies will have...

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Problems solved by technology

[0006] Due to the requirements of standards and specifications, when obtaining the material design allowable value test, the allowable value is not allowed to be extrapolated according to the test results or test curves, so the blanket curve method must be filled in the layup percentage of the test piece when planning the test piece entire Image 6 The shaded area shown in the figure results in a large number of test pieces and a long test cycle, and many test data are not used in the actual design of the aircraft, resulting in great waste

[0007] And the test piece of the design allowable value of compressive strength after impact of the composite material obtained by the AML method is in accordance with the requirements of the specification. The size of the test piece is "100mm×150mm" (element-level test piece). The actual situation such as load distribution has a great influence, and generally the test results obtained have a large deviation

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