Method for monitoring acting force between mold and member by fiber grating sensor

Abstract

The invention discloses a method for monitoring an acting force between a mold and a member by a fiber grating sensor. A basis is laid for quantitative research of the processes of accumulation and change of a residual stress of composite materials. When the acting force between the mold and the member in the forming process of the composite materials is monitored, the method includes following steps: firstly, an FEP thin film layer, a CFRP member pre-forming material, a mold plate, and a fiber grating sensor are laid on a support mold in sequence, and sealed via a vacuum bag; secondly, the fiber grating sensor is connected with a demodulation instrument, the forming is performed by employing the autoclave process, and the fiber grating sensor monitors the curing process strain in real time; and thirdly, acquired data is processed, and the debond stress and the sliding friction stress between the mold and the member are finally calculated. According to the method, the acting force between different molds and members in the forming process of autoclaves can be tested, the operation is simple, real-time monitoring is realized, and the accuracy is high.

Description

technical field [0001] The invention belongs to the field of evaluating the mechanical properties of composite materials, and in particular relates to a method for monitoring the force of a mold and a component by an optical fiber grating sensor. Background technique [0002] Carbon fiber reinforced composite (CFRP) components have been widely used in the aerospace field because of their excellent performance. However, the dimensional stability of the components is poor, adding time and cost to assembly. The residual stress generated by CFRP during the curing molding process will cause component deformation and affect the size of the material component. Correctly understand the formation process of residual stress, predict the deformation of CFRP components, and use this part of the deformation to make the final size of CFRP components meet the assembly requirements by modifying the mold and other means, which can greatly save manufacturing costs. [0003] Many factors aff...

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Problems solved by technology

Chinese patent 200910011933 "Fiber Bragg Grating Monitoring Method for Residual Strain of Composite Material Solidification" only provides a method for monitoring residual strain inside composite material components, without considering the force between the mold and composite material components

Foreign Kaushik et al. proposed a method for testing the static and sliding friction coefficient between mold components, which only explained the reason why the friction coefficient changes with the progress of the curing process, and did not provide an effective monitoring method for the mold-component force

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