Method for determining defects of multilayer binding vessel by acoustic emission

A determination method and acoustic emission technology, applied in the direction of material analysis using acoustic emission technology, can solve the problems that there is no analytical formula for calculating the stress analysis formula of the deep girth weld of multi-layer wrapped high-pressure vessels
CN101710105AInactive Publication Date: 2010-05-19SHANDONG UNIV +3
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
SHANDONG UNIV
Publication Date
2010-05-19
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to the technical field of safety assessment of pressure vessels with defects, in particular to a method for determining defects of a multilayer binding vessel by acoustic emission. Acoustic emission detection is carried out according to the structural features of the vessel so as to determine the defects. The method comprises the following steps of: (1) activating defects under overpressure, synchronously monitoring the defects in the vessel by acoustic emission, determining the overpressure during activating the defects and positioning the activated defect parts; (2) simplifying activated defects which cannot be determined by ultrasonic phased array rechecking according to the development direction of an acoustic emission event; (3) obtaining the stress distribution of the simplified defect parts by utilizing finite element calculation or a nomogram obtained on the basis of the finite element calculation so as to ensure that the simplified defects are on a maximum stress wall surface vertical to the simplified defects; and (4) based on defect simplification conditions, the stress of the simplified defect parts and material fracture toughness, reversely reasoning nominal initial sizes and tolerance sizes of the defects according to a fracture mechanics theory. The method has reliable detection means and reasonable simplification process and provides a foundation for the safety assessment of multilayer binding vessels.
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Description

1. Technical field

[0001] The invention relates to the technical field of remaining life assessment and safety assessment of pressure vessels, in particular to an acoustic emission determination method for defects in multi-layer wrapped vessels. 2. Background technology

[0002] Multi-layer wrapping structure (also known as laminate wrapping structure) is one of the typical structures of high-pressure vessels, and is widely used in the fields of chemical industry and petrochemical industry. Ammonia synthesis tower and urea synthesis tower, the core equipment in fertilizer production, usually adopt multi-layer wrapping structure, especially the urea synthesis tower has high working parameters and strict working conditions, and the materials contained in it are extremely corrosive. The typical features of the multi-layer wrapped urea synthesis tower are: the inner side in direct contact with the material is a urea-grade stainless steel lining with a thickness of 8 to 10 mm, an...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
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