共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
3.
4.
5.
根据冷却塔结构特点及其周边复杂环境情况,充分利用原开设缺口,合理布置减荷槽和定向窗简化爆破切口。针对钻爆参数及爆破网路进行优化设计,采取定向爆破倒塌方案。倒塌形式实质上是塔体扭曲变形失稳,具有倾倒趋势的坍塌或原地坐塌,使冷却塔在爆破过程中因自重作用而扭曲变形并触地解体,有效减少二次解体的工作量。针对电厂的特殊情况,爆破采用非电导爆管起爆系统起爆,最终成功实施了冷却塔的定向爆破拆除;通过稳定性验算确保预拆除安全;通过有效的防护体系和安全措施确保将爆破振动、个别飞散物和空气冲击波等爆破危害效应控制在安全允许范围内。 相似文献
6.
7.
8.
双曲线冷却塔是典型热电厂建筑设施,爆破采用预处理施工卸荷槽的控爆方法,在爆破缺口范围内倒塌中心线两侧对称布置了11条卸荷槽,高度4~11 m,由中间向两侧依次降低,使筒体在倾倒过程中,顺利产生了扭曲变形,成功地拆除了该塔。爆破效果较好。 相似文献
9.
介绍了永济市"上大压小"热电联产拆除工程中,在周围环境复杂的情况下,运用定向爆破技术拆除两座薄壁预制板拼接冷却塔和一座高支腿外循环冷却塔。针对薄壁拼接冷却塔自重小、结构单薄以及高支腿冷却塔重心高等特点,利用机械预拆除阶梯状大减荷槽、开设定向窗、环梁切口等措施,采用毫秒延期起爆和簇联接力复式网路,以及各种主动、被动安全防护,使爆破达到安全、经济、合理的目标。应用上述技术要点,成功拆除了三座特殊结构冷却塔。在复杂环境下特殊结构构筑物的爆破拆除工程中,做好试爆、预拆除环梁切口、减荷槽等工作对工程质量控制至关重要。 相似文献
10.
为成功拆除复杂环境下1座61 m高的冷却塔,根据其周边环境及结构特点,采用定向倒塌方案.首先采用机械方法开设定向窗和减荷槽,随后对19对人字柱进行爆破,使用毫秒延时爆破技术,控制单段起爆药量,成功完成拆除爆破.对拆除爆破后冷却塔的倒塌情况进行分析,冷却塔按照设计方向倒塌,解体完全,爆破振动以及触地振动控制在合理范围之内.爆破后周边民房、办公室等设施未损坏,证明本次拆除爆破效果良好,达到了预期效果,可为类似工程提供参考. 相似文献
11.
爆炸焊接过程中,焊接件界面温度的高低对焊接质量产生直接影响,因此爆炸焊接界面温度场是爆炸焊接理论研究的一个重要内容。通过对引起爆炸焊接界面温升的因素进行理论分析后,认为引起焊接界面温升的因素除了前人指出的基板和复板的冲击温升、畸形变形能温升之外,还应包括基板和复板之间的气体绝热压缩温升这三部分组成。其中基板和复板的冲击温升可由Hugoniot方程和自由电子气模型得出,畸形变形能引起的温升采用Johnson-Cook热黏塑性本构方程进行计算,气体绝热压缩引起的温升则通过气体的状态方程推导得出。 相似文献
12.
Behaviour of plate specimens subjected to underwater explosion is of interest to metal forming community and ship designers. The break down of the original molecule of an explosive into product molecules associated with the evolution of large amount of heat generates a shock front in the water medium, followed by a gas bubble pulsation. The interaction of the shock wave with a plate imparts energy to it, which is dissipated in the form of deformation. The intensity of explosion determines whether a plate undergoes elastic deformation, yielding, plastic deformation or fracture. When the deformation is in the elastic range, the stress developed in the plate is given as a function of the material and shock wave parameters. As the intensity of explosion progressively increases, the elastic to plastic transition occurs over a specific shock factor. Plastic deformation is predicted as a function of geometric and material properties of the plate and shock pulse impulse. Deflection-time history reveals the reloading effects of the shock wave. As the deforming plate absorbs maximum energy, depending on its strength and ductility, it undergoes fracture. Terminal strain to fracture is considered as the criterion for explosive shock performance of ship materials. 相似文献
13.
N.N. Thadhani 《Materials and Manufacturing Processes》1988,3(4):493-549
Shock compression processing is emerging as a novel technique for fabrication of esoteric materials. Not only can metal and ceramic powders be dynamically consolidated, but both equilibrium and non-equilibrium structures can be synthesized under the high pressure regime during the passage of shock waves of sufficient magnitude and duration. The shock waves can be generated by impact from a plate (accelerated by compressed gas or detonation of explosive) or direct contact with explosives. Very hard metallic and ceramic powders, as well as those powders that cannot be processed by conventional powder processing techniques can be easily compacted to solid densities. The bonding mechanisms in shock compaction involve the rapid and intense deposition of shock energy, preferentially at interparticle regions, resulting in extensive plastic deformation. This may lead to interparticle welding due to partial melting or simply solid-state diffusional bonding.
Shock compression processing technology will be reviewed with emphasis on the processing aspects. Specific examples of shock compaction of RSP alloys and ceramics will be presented, and feasibility of commercialization of the technique will be discussed. 相似文献
Shock compression processing technology will be reviewed with emphasis on the processing aspects. Specific examples of shock compaction of RSP alloys and ceramics will be presented, and feasibility of commercialization of the technique will be discussed. 相似文献
14.
为探究膨化硝铵炸药作用下,厚度均为2 mm的钛(Ti)、钢板的最优爆炸焊接参数以及验证一种新的爆炸焊接试验方案,实验采取阶梯型多层基板的爆炸焊接试验方案,以控制药量和间距为变量,并将Ti板作为复板,同时对多层阶梯型钢基板进行爆炸焊接试验;利用金相显微镜对焊接复合板进行观察,并分析多层基板同时焊接的方案可行性以及不同实验参数对界面波形的影响。试验结果和分析表明:通过观察Ti/钢复合板界面波形呈正弦微波状且无明显过渡层,验证了新方案的可行性,同时突出了阶梯型多层基板的同时爆炸焊接方案,能够在单次试验下对比分析不同基复板间距情况下的焊接效果的能力;并经分析得出在单位面积装药为1.048 g/cm~2及装药间距范围为(9~11)mm时,能得到质量较佳的Ti/钢爆炸复合板。 相似文献
15.
爆炸焊接理论与技术新进展 总被引:2,自引:0,他引:2
爆炸焊接理论与技术取得了四个方面的进展:(1)发现并重新定义了三种结合界面:大波状、小波状和微波状,其中以微波状为最佳.首次发现在一个复合板中,界面波呈一定的规律分布.(2)针对爆炸焊接熔焊机理的局限性,首次提出并验证了"爆炸焊接是一种特殊压力焊"的新观点.(3)为了得到无熔化的良好界面,必须选取焊接下限,按照新的复板模型,得到了新的焊接下限,比传统下限小20%,并适宜于工程应用.(4)首次测试并研究了爆炸焊接荷载下地基的应力应变规律.通过地基参数的优化分析,得到了最适宜于爆炸焊接的沙土地基(含水量17.00%、密度1.74g/cm3). 相似文献
16.
为实现对工业废弃物粉煤灰的剩余价值利用,尝试以粉煤灰作为主要原料制备焊接复合活性剂,并在AZ91镁合金板上进行A-TIG焊.利用焊缝的电特性实时采集、焊接温度场采集、电弧力测试等手段研究活性剂对电弧影响,通过熔池Bi粒子示踪实验探究活性剂对表面张力温度梯度影响.结果 表明:与常规TIG焊相比,粉煤灰复合活性剂可以使焊缝熔深增深1.4倍,熔宽减小,深宽比是常规TIG焊的1.43倍.粉煤灰复合活性剂中氟化物的解离和电离吸热过程、带电粒子的电子扩散和复合过程可以促进电弧收缩,使焊接电压升高,热输入量提高.而活性剂中的氧化物既可以通过对电弧的机械压缩作用强迫电弧收缩,又可以通过电离产生的氧元素实现对熔池液态金属表面张力温度梯度系数的改变,提高熔池中心热输入.A-TIG焊AZ91镁合金熔深增加是电弧收缩理论和表面张力温度梯度改变理论共同作用的结果. 相似文献
17.
18.
Explosive welding was used to produce scarf joint between aluminum and copper plates. This process is known as explosive scarf welding (ESW). In a scarf joint, the final bond interface is oblique. In this study, chamfered end of aluminum and copper plates were joined explosively and named scarf joint, employing changes in chamfered angle at different stand‐off distance and explosive loading. The geometry of scarf joint enables consideration of both flyer and base plate thickness and explosive loading and the effects on mechanical properties of interface such as bond shear strength and micro‐hardness can be investigated. Mathematical models developed on the interface properties of scarf joint to make relationship between the bond shear strength and explosive loading ratio. To check the adequacy of developed models, mechanical properties of interface, such as bond shear strength was predicted and compared with actual values in explosive cladding process. The results show reasonable agreement with theoretical predictions. Consequently, mathematical model which is based on scarf joints, can predict bond shear strength of cladding metals under desired explosive loading and flyer plate thickness. 相似文献
19.
针对爆炸粉末烧结过程中颗粒间的摩擦效应建立了无夹角斜碰撞模型,分析了烧结过程中颗粒间摩擦力随颗粒温度的变化规律,借助于LS-DYNA有限元程序对孔隙闭合时间进行了研究,并在此基础上用积分法对颗粒间热力耦合的摩擦力引起的界面温升进行了计算,在计算过程中考虑了颗粒尺度效应的影响,给出了发生“尺度效应”的临界尺寸。计算结果表明:材料的界面温升随着颗粒尺度的增大和冲击压力的变大而变大;当颗粒尺度从微米到纳米量级变化时,只有当颗粒尺度和冲击压力足够大时,颗粒表面温度才能达到材料的熔点。 相似文献