This work is concerned with the determining of physical and mechanical characteristics (dynamic elastic modulus along the direction of reinforcement, porosity, density, percentage of binder, strength) of fiberglass plastics by ultrasonic technique. The techniques, which are currently used for evaluation of the above-mentioned parameters of polymeric composite materials, are presented. The ultrasonic technique of physical and mechanical characteristics determining of glass fiber reinforced plastics for radio engineering purpose on the base of quarzitic, glass and siliceous fillers is proposed.
Fiberglass products after molding and heat treatment are impregnated with the organosilicon resin to increase heat resistance followed by polymerization by heat treatment. A method for non-destructive quality control of the composite-profile products impregnation made of fiberglass plastics with the organosilicon resin is proposed. Results of experimental work are presented on the study of alteration in the longitudinal ultrasonic waves speed in structural elements of the aerial vehicles made of fiberglass before and after impregnation with the organosilicon resin, i.e. the MFSS-8 product. Besides, alteration in the longitudinal ultrasonic waves speed in the fiberglass samples violating the impregnation technology are demonstrated.
The article discusses the existing methods of ultrasonic testing of polymer composite materials, reflected in the literature, allowing to determine the size of discontinuities, a method is proposed for determining the depth of folds of fiberglass products of complex shape by subsurface ultrasonic waves using original ultrasonic piezoelectric transducers with conical waveguides designed and manufactured. An experimental development of a method for determining the depth of folds of fiberglass products and a comparison of the results of ultrasonic testing with the results of X-ray computed tomography was carried out.
This article presents the results of an experimental study of the relationship of acoustic parameters (propagation velocity) of ultrasonic waves with elastic characteristics (elastic modulus) of polymer composite materials. Significant regression dependences of the correlation between the velocity of ultrasonic won and the modulus of elasticity of a composite material based on fiberglass with an epoxy and phenol-formaldehyde binder have been constructed.
This article describes the description and the results of experimental work to confirm the efficiency of the method for removing residual mechanical stresses in welded joints of NPP pipelines after they have been performed by ultrasonic hardening.Also, based on the results of the experiment, it is proposed to develop an automated device, the work of which is based on the proposed method.
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