Device and method for measuring internal stress of plastic sheet products on basis of ultrasonic lamb waves

Abstract

The invention discloses a device and method for measuring internal stress of plastic sheet products on the basis of ultrasonic lamp waves and belongs to the field of material performance detection. The device mechanically comprises a base, a longitudinal double-servo synchronous-drive moving component, a horizontal servo moving component and a test-piece clamping device; data collection processing and electric controlling systems transmit lamb wave signals on a digital oscilloscope to a computer processing system via a USB (universal serial bus), amplitude signals are processed to acquire stress distribution on different areas, and the electric controlling system controls a servo two-dimensional mobile platform to realize measurement of the different areas. The device and method is high in integration degree and simple in operation, standard splines are calibrated with the lamb wave amplitude signals under different stresses, and quantitative measurement of the internal stress distribution of the plastic sheet products can be realized by detection of lamb wave amplitudes.

Description

technical field [0001] The invention relates to a device and method for measuring the internal stress of plastic thin plate products based on the principle of ultrasonic Lamb wave propagation, belonging to the field of performance detection of plastic thin plates. Background technique [0002] Plastic thin plate products, especially engineering plastic thin plate products (thickness 0.1 ~ 15mm) are widely used in high-tech fields such as aerospace, automobile industry and medical equipment. However, during the processing and molding process, due to the influence of comprehensive factors such as the cooling rate of the melt in the mold, the uneven flow rate, or the uneven plasticization of the melt itself, internal stress is generated on the surface of the final formed thin plate product. The existence of such internal stress on the surface will cause warping and deformation of the thin plate products and even produce fine cracks on the surface of the products, which will eve...

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Problems solved by technology

[0017] The purpose of the present invention is to provide a device and method for measuring the internal stress of plastic sheet products by ultrasonic Lamb wave, which can not realize the non-destructive and rapid quantitative measurement of different regions in view of the existing device for measuring the internal stress of plastic sheet products. The propagation characteristics of M-wave in thin plate medium, based on the Clapeyron strain energy principle and the theory of the relationship between the structure and performance of polymers, through the horizontal and vertical servo motors to drive the movement of the two-dimensional platform of the plastic sheet product fixture, to realize the plastic sheet product Quantitative determination of stress distribution

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