金属爆破片爆破性能及影响因素数值研究

发布时间：2018-02-27 19:25

本文关键词： 正拱爆破片反拱爆破片爆破压力失稳压力有限元分析　出处：《大连理工大学》2012年硕士论文　论文类型：学位论文

【摘要】：金属爆破片已成为防止流体压力设备发生超压的最有效的装置之一,研究其爆破性能及影响因素对设计、制造及使用具有重要指导意义。采用实验方法研究爆破性能耗时、耗力、耗资。随着有限元技术的发展,数值模拟已成为开展此方面研究的重要手段。本文运用弹塑性理论,采用薄壳大塑性变形有限元分析方法,分别研究了正拱普通型、正拱带槽型、平板带槽型及反拱型爆破片的爆破性能,探讨了影响其爆破性能的因素。本文主要研究内容及结论如下： (1)建立了普通正拱型爆破片爆破数值模拟模型。将数值模拟结果与试验结果对比,验证了数值模拟的正确性。基于此模型,系统研究了普通正拱形爆破片预拱成形压力与拱高之间的关系,及根部圆角和成型压力对爆破性能影响。结果表明,夹持圆角为膜片厚度的5倍时拱顶应力最小；预拱成型压力为爆破压力的90%时拱顶应力最小；建立了较精确的奥氏体不锈钢爆破片预拱成形压力与拱高之间关系式。 (2)建立了正拱十字槽型爆破片数值模拟模型,对比发现模拟结果与试验结果吻合较好。研究了十字形减弱槽形状和长度对爆破压力的影响,结果表明,顶部十字交叉未贯通长度在2.5mm-4mm,减弱槽端距拱面底部距离在1mm-5mm时,对爆破压力产生的影响可以忽略；与矩形槽、弧形槽相比而言,v形槽有较大的承载能力。 (3)建立了平板环槽型爆破片数值模拟模型。研究了膜片厚度、减弱槽深度和数量对爆破压力的影响,结果表明,当槽深余厚相同时,坯片厚度越大,承受能力越小；槽深余厚与爆破压力成线性关系；刻槽条数增加,爆破压力和变形高度增加。 (4)采用材料非线性和几何非线性的分析方法,建立了反拱形爆破片失稳数值模型,获得了反拱形爆破片的失稳压力,数值模拟结果与试验结果吻合较好。分析了拱高、膜片厚度、口径及边界约束类型及强度失稳载荷的影响规律,通过大量的算例并结合试验,总结出了反拱型爆破片失稳载荷计算公式。 (5)定义了反拱形爆破片受损范围的概念,系统研究了拱顶损伤与非拱顶损伤对爆破片失稳压力的影响,确定了损伤尺寸与失稳载荷之间关系。得出了可以忽略损伤影响的最小损伤直径；在具有相同损伤尺寸下,拱顶损伤失稳压力为非拱顶损伤的0.7倍,拱顶损伤对爆破片失稳压力影响最大；重点分析了夹持条件对失稳载荷的影响,得出了不同边界约束对失稳压力的影响程度。
[Abstract]:Metal blasting disc has become one of the most effective devices to prevent overpressure in fluid pressure equipment. It is very important to study its blasting performance and its influencing factors to design, manufacture and use. With the development of finite element technique, numerical simulation has become an important means of research in this field. In this paper, elastoplastic theory and finite element analysis method for large plastic deformation of thin shell are used to study the normal arch type, respectively. The blasting performance of the positive arch with groove, the flat plate with groove and the reverse arch blasting disc is discussed, and the factors influencing the blasting performance are discussed. The main contents and conclusions of this paper are as follows:. 1) the numerical simulation model of normal arch blasting disc blasting is established. The correctness of the numerical simulation is verified by comparing the numerical simulation results with the experimental results. The relationship between pre-arch forming pressure and arch height and the effect of root angle and forming pressure on the blasting performance are studied systematically. The results show that the arch stress is the smallest when the clamping angle is 5 times the thickness of the diaphragm. The prearch forming pressure is 90 times of blasting pressure, and the relation between pre-arch pressure and arch height of austenitic stainless steel blasting disc is established. (2) the numerical simulation model of the cross groove blasting disc is established. The results of the simulation are in good agreement with the experimental results. The influence of the shape and length of the cross-shaped weakened groove on the blasting pressure is studied. When the length of the cross at the top is 2.5mm-4mm and the distance from the end of the groove to the bottom of the arch surface is 1mm-5mm, the influence on the blasting pressure can be neglected, and compared with the rectangular groove and the arc groove, the V-shaped groove has a larger bearing capacity. The numerical simulation model of flat plate annular groove blasting disc is established. The effects of diaphragm thickness, depth and quantity of reducing groove on blasting pressure are studied. The results show that the bigger the slab thickness is, the smaller the bearing capacity is when the residual thickness of groove depth is the same. The residual thickness of the groove is linearly related to the blasting pressure, and the number of slots increases, and the blasting pressure and deformation height increase. 4) the numerical model of the instability of the reverse arch blasting disc is established by means of material nonlinearity and geometric nonlinearity, and the unstable pressure of the reverse arch blasting disc is obtained. The numerical simulation results are in good agreement with the experimental results, and the arch height is analyzed. The influence of diaphragm thickness, caliber and boundary constraint type and strength instability load is studied. Based on a large number of examples and experiments, the formula for calculating the unstable load of anti-arch blasting disc is summarized. In this paper, the concept of damage range of anti-arch blasting disc is defined, and the influence of damage on the unstable pressure of blasting disc is studied systematically. The relationship between damage size and unstable load is determined, and the minimum damage diameter which can be neglected is obtained. Under the same damage size, the damage instability pressure of vault is 0.7 times that of non-arch damage. The damage of arch roof has the greatest influence on the unstable pressure of the blasting disc, and the influence of clamping conditions on the unstable load is analyzed, and the degree of influence of different boundary constraints on the unstable pressure is obtained.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH49

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