Composite material I-type layered bridging law determination method based on correction beam theory

A technology for composite materials and determination methods, applied in the fields of electrical digital data processing, instruments, computer-aided design, etc., can solve problems such as equipment errors and lack of versatility, and achieve the effect of avoiding calculation costs and reducing test devices

Active Publication Date: 2020-06-26
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method is easy to implement but requires constant adjustment of the camera focal length to focus on the crack tip position during the test, which undoubtedly introduces equipment errors
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Method used

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  • Composite material I-type layered bridging law determination method based on correction beam theory
  • Composite material I-type layered bridging law determination method based on correction beam theory
  • Composite material I-type layered bridging law determination method based on correction beam theory

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Embodiment

[0029] Implementation example: Determination of type I delamination bridging law of unidirectional laminate test piece using glass fiber / EPON 828 resin matrix composite material

[0030] 1. Geometric description

[0031] The thickness of the unidirectional laminate DCB test piece is 4.45mm, the width is 25mm, and the length is 150mm. The initial prefabricated delamination length is 35mm, and the initial delamination position is located at the middle thickness of the test piece. The ply order of the laminate is [0°] 24 , the material property of the unidirectional belt is: E 1 =35.25GPa,E 2 =E 3 =10.82GPa,G 12 =G 13 =G 23 =4.28GPa, ν 12 = ν 13 = ν 23 = 0.47.

[0032] 2. Carry out type I delamination test of composite material laminates, and measure its P-δ curve;

[0033] (A) Use the fast clamping hinge clamp to clamp the DCB sample to the MTS testing machine. After the clamping is completed, ensure that the sample is in a straight state as much as possible without a...

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Abstract

The invention relates to a composite material I-type layered bridging law determination method based on a modified beam theory, which comprises the following steps: (1) carrying out a composite material laminated plate I-type layered test, and measuring a P-delta curve of the composite material laminated plate I-type layered test; (2) establishing a two-dimensional correction beam mechanical modelof the sample under the I-type load; (3) inputting the P-delta curve, the material basic attribute and the geometric dimension into the model calculation program, performing iterative calculation inMatlab software, and determining a layering length a, an initial crack tip opening displacement delta * and an energy release rate GIc; and (4) establishing a relationship between GIc and delta * to obtain a bridging law sigma g (delta *). The method is suitable for determining the bridging law in the I-type layered expansion process of the composite laminate at any laying angle, and has the advantages that (1) the method only needs to take the P-delta curve of the sample as input, the crack position does not need to be observed, and test devices are reduced; (2) the method is realized by using a Matlab program, so that the calculation cost is relatively low; and (3) the method can be used for determining the I-type bridging law of the composite laminate at high temperature.

Description

technical field [0001] The invention relates to the determination of the bridging law in the process of delamination expansion of composite material laminated boards under the action of I-type load, and is suitable for resin-based composite material laminated boards widely used in aerospace vehicle structures. Background technique [0002] Fiber-reinforced composites are widely used in aerospace structures due to their excellent mechanical properties such as high specific strength, specific stiffness, and corrosion resistance. However, due to its weak interlayer properties, it is highly prone to delamination, leading to severe damage to the structure without any external signs. Therefore, accurately simulating the delamination behavior of fiber-reinforced composites is crucial in structural design. However, fiber reinforcement and material delamination are often accompanied by large-scale fiber bridging. The existence of fiber bridging makes the stress distribution at the c...

Claims

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Application Information

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IPC IPC(8): G06F30/23G06F113/26G06F119/14
Inventor 赵丽滨曹天成马晨曦骈瑢
Owner BEIHANG UNIV
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