Research On Dynamic Measurement Method Of Material Welding Deformation Based On Digital Image Correlation Method

Material weldment in the aviation industry,automobile industry,shipbuilding industry occupies the important position,the application materials in welding of high temperature mechanical properties research is to ensure that the structure of normal use in industrial or life key,the welding strain detection is one of the important basic research in materials forming mechanics,the current in the welding materials strain measurement is the bottleneck,In addition,the reliability and feasibility of traditional measurement methods(such as strain gages,etc.)cannot be guaranteed at high temperature and high temperature,the measurement efficiency is low,and the full-field strain results cannot be obtained,and it is also difficult to be applied to the measurement of welding parts.Based on visual dynamic measurement technology based on digital image correlation method and the method of simulation analysis,the related key technologies are studied and improved,and put forward to satisfy the requirement of the material welding deformation strain vision measuring technology solutions,measurement results from the technical scheme can effectively guide the design and production of material welding,improve the efficiency of product development.The main research work includes:(1)A high-temperature-resistant digital image speckle specimen was prepared that overcomes the problem of “weak correlation phenomenon” in speckle images in the visual dynamic measurement of material welding deformation.Designed different high-temperature resistant speckle pattern schemes,studied the high-temperature speckle preparation process,and focused on the influence of different speckle spacing and high-temperature glue ratio on the speckle quality.The experimental results show that: when the white speckle spacing is At 4.5mm,the deformation cloud image calculated from the speckle image has no "holes";when the inorganic silicate powder and high-temperature inorganic glue are prepared in a ratio of 1ml:1.5g,the high-temperature resistant speckles will not fall off in the welding high-temperature environment,and Effectively overcome the "weak correlation" problem of speckle images.(2)Aiming at the problem of speckle image noise reduction in the visual dynamic measurement of material welding deformation,a method to reduce the noise of high temperature speckle image is proposed.Analyzed Planck's law of radiation and analyzed the wavelength range accepted by the camera,and studied the influence of welding temperature on the radiation energy;comparative experiments were carried out using optical filters of different bands,and the influence of thermal radiation on speckle images was studied;Optical properties and local strong light principle,the use of optical polarizer method reduces strong light noise and improves image quality.The experimental results show that: in the camera's wavelength range of 400nm-700 nm,as the temperature rises from 100 K to 1800 K,the radiation energy follows Increase,causing the impact on the image quality,the use of optical filters with a wavelength of420nm-450 nm can effectively eliminate,while the use of optical polarizers can effectively eliminate the glare on the image.(3)In order to test the effectiveness of the visual dynamic measurement method of material welding deformation,the welding numerical simulation method based on simufact software was used to establish the theoretical value of material welding deformation displacement and the law of temperature change.Establish welding model and welding heat source model,set different welding parameters,and obtain the law of temperature change and the law of material strain displacement change and the theoretical value of the material under different welding parameters.(4)Research and design an experimental device for the visual dynamic measurement of material welding strain at high temperature,and the experimental research on the visual dynamic measurement of material welding strain.The comparison between the simulation experiment results of material welding based on simufact software and the visual dynamic measurement experiment shows: visual dynamic measurement value The change law of the theoretical value is basically consistent;in the visual dynamic measurement method,the maximum deformation displacement of a single point at the material weld is 0.148 mm and 0.144 mm,and the theoretical values of the corresponding points are 0.165 mm and 0.221 mm,respectively,and the error is 0.017.mm and 0.077 mm.The strain visual dynamic measurement technology of material welding proposed in this paper is feasible and effective.