CAJ | 학술논문

膨胀管膨胀后其抗外挤能力降低是制约膨胀管技术发展的重要因素。通过试验模拟实体膨胀管膨胀时的力学环境，分析了管材壁厚及残余应力在塑性膨胀过程中的变化规律。结果表明：膨胀管大塑性变形会导致壁厚减少，壁厚不均匀程度放大，并产生残余应力；膨胀管内表面产生拉应力，外表面产生压应力，应力差值在薄壁端最大，薄壁端也是膨胀管在外压作用下的屈服点；在膨胀管变形过程中薄壁端的变形速率高于厚壁端的变形速率，产生的残余应力与实测值基本相符，说明膨胀管原始壁厚的不均匀变形是残余应力增加、抗外挤能力降低的主要因素。
팽창관팽창후기항외제능력강저시제약팽창관기술발전적중요인소。통과시험모의실체팽창관팽창시적역학배경，분석료관재벽후급잔여응력재소성팽창과정중적변화규률。결과표명：팽창관대소성변형회도치벽후감소，벽후불균균정도방대，병산생잔여응력；팽창관내표면산생랍응력，외표면산생압응력，응력차치재박벽단최대，박벽단야시팽창관재외압작용하적굴복점；재팽창관변형과정중박벽단적변형속솔고우후벽단적변형속솔，산생적잔여응력여실측치기본상부，설명팽창관원시벽후적불균균변형시잔여응력증가、항외제능력강저적주요인소。
The drop of the collapse strength of the solid expandable tubular after expansion was the key factor restricting the development of expandable tubular.In this paper the mechanical envi-ronment of the tubular being expanded was simulated through experiments and the change of the tubular wall thickness and the residual stress during the expansion were explored.The results demonstrated that the plastic deformation of the tubular led to the increase of the eccentricity and residual stress,the inner surface of the tubular was seen the tensile stress while the outer surface compressive one,the deviation reached the maximum in the position of the least wall thickness which was also the starting point of the collapse;the FEA simulation showed that the thinner the wall thickness is,the bigger the expansion ratio,the residual stress is compatible to the tested re-sults,reinforcing the theory that the eccentricity of the tubular is the key to the increase of residu-al stress and drop of the collapse strength.