Infrared lock-in thermography defect identification method for honeycomb sandwich structure

Abstract

The invention provides an infrared lock-in thermal imaging defect identification method for a honeycomb sandwich structure, which includes: S1, adopting an infrared lock-in thermal imaging detection method to construct an analytical model of the temperature change and distribution of the test piece; S2, adopting a digital The phase-locking method extracts the amplitude and phase information of the steady-state or quasi-steady-state process in the temperature signal, and uses the influence of the defect on the phase information to obtain the defect characteristics; S3. Build a finite difference model of the heat conduction process, and derive radiation and convection effects. The heating surface temperature of the specimen is determined; S4, establish the thermal and electrical equivalent model of the heat conduction process, and confirm the existence of the defect. The present invention fully considers constant heat flow, alternating heat flow and the influence of lateral thermal diffusion in the honeycomb sandwich structure, and is effective for the detection process range of different types and depths of defects and the detection of different defects.

Description

Technical field [0001] The present invention belongs to the field of non-destructive detection technology, particularly an infrared lock-sensitive imaging defect identification method for a honeycomb interlayer structure. Background technique [0002] The honeycomb interlayer structure has been adventive and rapidly has been widely used in various fields, which is much easier and rigid compared to traditional materials and structures. It is extremely obvious to product weight loss. Due to the difficult control of various process parameters during the manufacturing process, the honeycomb interlayer structure is easily caused by unstable mass, large discrete properties, debris, stratification, adverse grease, air hole, inclusion, and honeycomb cell deformation. The detection effect and efficiency of traditional rays, ultrasound, etc. are not good and need to be improved. In this context, the infrared thermal imaging detection method is promoted, in which the infrared lock-sensitive...

AI Technical Summary

Problems solved by technology

According to the analysis of infrared lock-in thermal imaging detection principle, the process parameters in the detection process include band range, integration time, thermal sensitivity, loading amplitude, loading frequency, loading cycle, phase-locking frequency, phase value, environmental impact and loading distance, etc. Influencing factors, it is difficult to effectively determine the detection process of products with different structures, thicknesses and sizes by using traditional process test methods

Images