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Design and Research of Ultrasonic Impacting Equipment for Relieving Welding Residual Stress

Author: QinLei
Tutor: LiuJie
School: Northeastern University
Course: Mechanical and Electronic Engineering
Keywords: Welding residual stress Ultrasonic Impact Giant magnetostrictive material Transducer Horn Frequency tracking
CLC: TG404
Type: Master's thesis
Year: 2008
Downloads: 114
Quote: 2
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Abstract

Welded structure is widely used in the related fields of the national economy, it can be said to promote the development of modern industrial welded structure in a certain extent. However, due to the presence of welding stress and deformation directly affect the performance of welded structures, security, reliability and manufacturability. So it has been one of the important issues of concern for the welding industry. The ultrasonic impact the new law is to improve an after welding Welding Residual Stress craft. The study focused on the impact of ultrasound equipment used in this method. Ultrasonic impact technology is the use of high-power ultrasonic frequency of 20,000 times per second, more than the impact of the metal surface, the metal surface to produce greater pressure plastic deformation due to the high frequency of the ultrasonic energy efficient and focused, promoting impact tools ; same time ultrasound shock waves to change the stress field, to produce a certain value of compressive stress; ultrasonic impact site to be strengthened. In this paper, based on the analysis of the structure and function of the impact of ultrasound equipment to improve the welding residual stress, establishes the overall scheme of the ultrasonic shock device. The ultrasonic impact device consists of two parts: ultrasonic generator and implementing agencies. Implementing agencies including ultrasonic transducer, the horn and the impact head. The ultrasonic generator should have a main loop, to generate sufficient power and alternating current of the desired frequency and the frequency tracking control system and the output power control system. Since rare earth giant magnetostrictive material is today room temperature the material has a maximum magnetostriction coefficient, an order of magnitude higher than the piezoelectric ceramic, giant strain at a low magnetic field can be obtained, and having a high electromechanical coupling coefficient, high energy density, in response to speed advantages. This paper to design a super-magnetostrictive transducer as the implementing agency of the core components of the calculation for super-magnetostrictive transducer design its specific structure and size to draw out some of the parts, application software CAXA two-dimensional map, as well as super-magnetostrictive transducer overall structure diagram, and then apply CATIAV5 software transducer assembly modeling of 3D visualization entities. And by calculating the design of the conical horn and impact head applications CATIAV5 software, solid modeling of a three-dimensional visualization of the horn and the impact head. Analysis of ultrasonic impact treatment process, to understand the power and frequency change of the actual work, analysis of the electro-acoustic characteristics of the ultrasonic shock device acoustic and ultrasonic impact treatment characteristics of the ultrasonic generator function and structure of the overall design philosophy, the establishment of the ultrasonic occur is the main loop, the completion of the ultrasonic generator automatically track the resonant frequency and output power circuit of the automatic control system design, phase and frequency automatic tracking system MATLAB simulation. In the article, the entire paper summarized and presented the outlook for future work.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Welding, metal cutting and metal bonding > Welding general issues > Stress and deformation of welded structures
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