摘要本文对T型约束结构焊接接头通过盲孔法测量焊接残余应力；对多层多道焊进行单层焊接应力、应变测量。

在盲孔法应用中确定了电阻应变片选择、粘贴工艺、计算公式、测量工艺以及对残余应力释放系数A、B进行修正，A为-0.34677，B为-0.78628。

在焊缝范围内，从焊缝中间到熔合线，焊接残余应力增大到将近两倍。因为处于熔合区，成分不均匀导致应变很大；熔合区是液固变化区，其受力不均匀，因此该区域应力很大。

在距焊缝15mm的热影响区范围内，由于热影响区处于热固变化区，所以离焊缝越远最大主应力越大，而最小主应力越小；当焊接过程会累积热量并且受热不均匀，所以在距焊缝15mm的热影响区范围内，距焊缝相同距离的监测点，沿着焊接方向主应力值增大。当焊接过程已经累积一定的热量并且热应力场已经趋于稳定，所以在距焊缝15mm的热影响区范围内，距焊缝相同距离的监测点，沿着焊接方向主应力值减小。68177

毕业论文关键词    焊接残余应力    盲孔法   多层多道焊接   应变实时监测

毕 业 论 文 中 文 摘 要

毕 业 论 文 外 文 摘 要

Title     Testing and research on stress of steel structure              

Abstract

The T-welded joint binding structure was measured welding residual stress through the blind hole method , and to multi-layer multi-channel welding for welding stress and strain measurement.

In the blind hole method was used to determine the resistance strain gauge selection, paste process, formula, measuring process and the residual stress release coefficient to modify A, B, A is -0.34677, B is -0.78628.

Within the scope of the weld seam , from the middle of weld to the fusion line, the welding residual stress increases to nearly twice as much. Because in the fusion zone, uneven composition leads to strain a lot; Fusion zone is liquid-solid transition zone, and its stress is not uniform, so the stress of this area is very large.

In 15 mm away from the weld heat affected zone, due to the heat affected zone in thermosetting change area, the farther from the weld  larger maximum principal stress is larger, and the minimum principal stress is smaller; When welding process will accumulate heat and heat unevenly, so from the weld heat affected zone of 15mm, the same distance from the weld monitoring points along the welding direction of principal stress value increases. When the welding process has been accumulating heat and thermal stress field has stabilized, so 15mm from the weld heat affected zone within the same distance from the weld monitoring points along the welding direction of principal stress value decreases.

Keywords   welding residual stresses    blind hole method    multi-layer multi-pass welding     real-time monitoring of strain

目   次

1  绪论 1

1.1  钢结构焊接研究前景 1

1.2  焊接应力研究的国内外研究现状 2

1.2.1  模型法的研究概况 2

1.2.2  焊接应力测量研究概况 3

1.3  课题研究的内容 4

2  应力应变测量方法及设备 5

2.1  应变的测量研究 5

2.1.1电阻应变片测量 5

2.1.2盲孔法 7