Study On Residual Stress Measurement Of Composite Curing Based On Cutting Groove Method

The application and development of any new material is bound to rely on more and more application needs.In modern society,people are concerned with the energy saving of vehicles,the travel safety of airplanes and automobiles,the increasing demand for the portability of wearable devices and sports equipment.Traditional lightweight metals are difficult to meet the requirements of high reliability and low density at the same time.Therefore,carbon fiber composite materials emerge as the times require and have achieved great development.Benefiting from its unique advantages of high strength,low density and high reliability compared with traditional metal materials,it has achieved great development and application in aerospace,military equipment,automobile manufacturing and other fields.The curing process of composites is a key step to ensure the properties of the final articles.Due to the physical and chemical reaction process in the curing molding process,the temperature fielded and degree of curing in the article are not evenly distributed,which eventually evolves into the residual internal stress in the article and the final curing deformation,which has an impact on the size,quality and mechanical properties of the article.Therefore,the measurement of the internal residual stress of composite materials has become a very important link to the practical application of composite materials.At present,the measurement direction of material internal residual stress mainly includes two categories of lossy measurement method and nondestructive measurement method and the lossy measurement method with low cost and small operation difficulty is the most widely used in industry.In this paper,several shortcomings of the incremental cutting method of composite material loss measurement are studied and improved on composite material-metal laminate articles.(1)By looking at the domestic and foreign related research literature,determine the test method of the residual stress measurement experiment,and according to the research object of aluminum alloy-composite laminate structure of known thermal chemical parameters and mechanical parameters determine the resin curing kinetics model and the heat transfer model to simulate the artifacts in the curing process.The results are compared with the actual stress measurement data to verify the correctness of the simulation results.(2)Aimed at cutting groove method of uncertain measuring residual stress articles are the most representative site faults,using the method of combining the simulation model and test data,obtain the planar structure of metal-composite laminate structures in the best position when using the damage measurement method,based on the parametric study.(3)In view of the distortion of the measurement results caused by gravity factors of the cutting groove method,the finite element simulation model was verified by the test data,and the experimental data were parameterized by the finite element simulation results to obtain the influence of gravity factors of the measurement accuracy of residual stress under the test conditions.The finite element model is used to parameterize the influence of gravity factors.(4)In the cutting groove method,the repeated cutting measurement of the same article will cause mutual influence and make the measured data deviate from the actual value.Using finite element simulation to predict the repeated slitting safe distance,and the experiment article was tentatively cutted,proved that the finite element simulation method of repeated slitting safe distance prediction feasibility,and on this basis,the safe distance for the overlapping segmentation for the parametric study,present the corresponding change rule.