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在承受压力荷载的钢结构杆件中,残余应力对其承载性能会有显著影响。早期在残余应力及柱的强度方面的试验研究,只是针对中小型型钢进行的。目前使用重型型钢的大型结构日益增多,重型型钢的应用虽然已经相当广泛,但关于这类杆件的残余应力及强度方面可利用的资料却非常缺乏。 本文介绍用于受压杆件的厚板和重型型钢的残余应力及其性能方面的第一阶段研究成果.在初期研究中,所考虑的为型钢15H290和23H681,以及两个无约束钢板PL16×2和PL24×3 1/2试件,对于较小的型钢,则按其钢板的不同加工条件(万能轧钢机轧制和火焰切割),不同焊接类型(熔透)及不同的屈服强度进行对比试验. 在研究工作的第一阶段,重型杆件的实测残余应力值显示了下列各点: 1.所有制造和加工过程,通常都会影响残余应力的形成. 2.焊接类型(熔透)和钢材屈服强度不是形成残余应力的主要因素。 3.钢板和型钢的几何尺寸是影响残余应力值及其分布的重要因素之一。 4.板厚大于1英寸时,残余应力沿厚度方向的变化会相当可观。 5.在焊缝面积以外的横截面部分中,焊接残余应力有随杆件尺寸增加而减少的趋势,这可能是由于重型型钢和钢板的焊缝区域及其热输入量较之轻型杆件相对小一些的缘故。 6.初始应力值可能高于焊接残余应力。 由部件钢板的初始残余应力与焊接残余应力间的相互关系可以看出,为了限制焊接重型型钢的残余应力,应在部件钢板的制造方面下功夫。这样,在使用火焰切割钢板时,焊接重型型钢的强度有可能较之相同细长比的焊接轻型杆件高,甚至有可能比相应的轧制杆件还要高些。
In steel bars subject to compressive loads, the residual stresses have a significant effect on their load-bearing properties. Early experimental studies on the residual stress and the strength of the column were conducted for small and medium size sections only. The current large-scale use of heavy-duty steel structure is increasing, although the application of heavy-duty steel has been quite extensive, but the residual stress and strength of such materials available on the pole is very scarce. This paper presents the first phase results of the residual stresses and their properties of thick and heavy section bars subjected to compression bars.In the initial study, the sections 15H290 and 23H681 and the two unconstrained plates PL16 × 2 and PL24 × 3 1/2 specimens. For smaller sections, the comparison is made according to the different processing conditions of the steel sheet (universal mill rolling and flame cutting), different weld types (penetration) and different yield strengths Tests In the first phase of the research work, the measured residual stress values for heavy bars show the following points: 1. All manufacturing and machining processes normally affect the formation of residual stresses 2. Weld type (penetration) and steel Yield strength is not the main factor in the formation of residual stress. 3. The geometric size of steel plate and steel is one of the important factors affecting the residual stress value and its distribution. 4. Thickness greater than 1 inch, the residual stress along the thickness of the change will be considerable. 5. In the cross-sectional area outside the weld area, the welding residual stress tends to decrease as the size of the rod increases, probably due to the weld area of the heavy section steel and steel plate and its heat input relative to the light rod Smaller sake. 6. The initial stress value may be higher than the welding residual stress. It can be seen from the correlation between the initial residual stress and the welding residual stress of the component steel plate that in order to limit the residual stress of the welded heavy section steel, efforts should be made to manufacture the component steel plate. In this way, when using flame-cut steel, the strength of the welded heavy section steel may be higher than that of a welded light rod of the same slenderness ratio, possibly even higher than that of the corresponding rolled rod.