Shaped Charge Optimisation against Bulging Targets

Equivalent to the results against explosive reactive armour sandwiches also bulging armours can be better defeated by high performance precision shaped charges compared to so‐called robust shaped charges. The shaped charges with larger liner angles or thicker liners have less jet tip velocities which results in less residual penetration capabilities.     

换热器管板胀接槽的加工

介绍换热器的铝管与合金结构钢的管板胀接结构,并介绍加工管板孔槽的工艺装备。     

超声振动效应对TA2钛合金板材力学及胀形性能影响

针对钛合金板材塑性变形能力差的问题,进行了超声振动辅助成形工艺的研究,分析超声振动对钛合金TA2板材力学性能及与接触面之间摩擦系数的影响。在此基础上进行了不同宽长比坯料的超声振动辅助胀形实验,分析超声振动对TA2板材胀形力、极限胀形高度的影响。同时,基于网格应变原理,通过不同宽长比坯料极限应变的测量,建立TA2板材的成形极限图。研究结果表明,选择合适的超声振动辅助成形工艺参数, 不仅可以提高TA2板材变形能力,还可以减小摩擦对板材成形性能的影响,从而有效提高了TA2板材的成形极限。     

Control of mold level in continuous casting based on a disturbance observer

Regulating molten steel level in continuous casting is difficult because it suffers from various disturbances, among which the bulging disturbance is the most prominent. Moreover, as the casting speed increases in continuous casting, the phase lag due to the system delay increases. To eliminate the bulging disturbance in the presence of system delay, we propose an adaptive sine estimator based disturbance observer and a phase lead adaptive fuzzy controller. We tested the proposed method using a 1:1 scale hardware simulator and confirmed that the method successfully decreased the bulging disturbance effect from the molten steel level.     

Laboratory model studies on unreinforced and geogrid-reinforced sand bed over stone column-improved soft clay

Results from a series of laboratory model tests on unreinforced and geogrid-reinforced sand bed resting on stone column-improved soft clay have been presented. The diameter of stone column and footing has been taken as 50 mm and 100 mm, respectively for all the model tests carried out. Load was applied to the soil bed through the footing until the total settlement reached at least 20% of footing diameter. As compared to unimproved soft clay, the increase in load-carrying capacity under different improved ground conditions has been observed. Influences of the thickness of unreinforced as well as geogrid-reinforced sand bed and the size of geogrid reinforcement on the performance of stone column-improved soft clay bed have also been investigated. Significant improvement in load-carrying capacity of soft soil is observed due to the placement of sand bed over stone column-improved soft clay. The inclusion of geogrid layer within sand bed further increases the load-carrying capacity and decreases the settlement of the soil. Due to the placement of sand bed, the bulge diameter of stone column reduces while the depth of bulge increases. Further reduction in the bulge diameter and increase in bulge depth are observed due to application of geogrid layer. The optimum thickness of unreinforced sand bed is twice the optimum thickness of geogrid-reinforced sand bed. Under specific material properties and test conditions, it is further observed that the optimum diameter of geogrid layer is thrice the diameter of footing.     

茶壶橡胶胀形工艺及模具设计

文中分析比较了茶壶新旧两种成形工艺，叙述了橡胶胀形加工的优点，对毛坯尺寸及胀形力进行了计算，介绍了铝合金茶壶橡胶胀形模具结构。     

内压下破裂壳体结构的膨胀系数和几何非线性响应

基于裂缝边缘中心的横向或面外非线性动力响应,给出一种可行的方法以替代用于损伤容器设计的膨胀系数,并用以描述施加内压的破裂柱状壳体结构的特性。该法避免了膨胀系数的有限元分析中裂缝端网格选择的问题,还指出裂缝长度和裂缝宽度对响应的影响相同。发现裂缝宽度对响应的影响有重要的意义,但其在膨胀系数中是无用的。而且,目前单个膨胀系数仅适用于裂缝长度和壳半径比在某个范围的情况。研究表明:1)本文给出的方法不受裂缝长度与壳半径比值范围的限制;2)该法概念简单;3)从计算上看,由于目前的动力方法在粗网格处会快速收敛,通过使用基于壳体有限元的混合公式可以相对更加容易且准确有效地获得裂缝边缘中心的非线性响应。     

薄壁钢管成型鼓包解决方法浅析

薄壁钢管在各行业中的应用非常广泛。在生产薄壁钢管时遇到的一个共性问题是成型鼓包。引起鼓包最根本的原因是带钢边缘延伸超出了该材料的弹性极限范围。从变形原理入手,分析了产生鼓包的原因,着重从原料、工艺布局和轧辊孔型设计等方面提出了解决鼓包的一些方法。     

Hydromechanical deep-drawing of aluminum parabolic workpieces—experiments and numerical simulation

Aluminum parabolic workpieces were formed with hydromechanical deep-drawing technology. The deep-drawing process was analyzed by using the explicit finite element method with various process parameters. Defects of wrinkling and rupture are predicted for some forming conditions, and the thickness distribution results are in good agreement with the experimental results. Thinning mainly takes place during the first third of the punch travel, while wrinkling mainly takes place during the final half-stage of the punch travel. The effects of chamber pressure and blank holding force on the deformation of the workpieces are discussed. The numerical results are compared with those obtained in the experiments.     

低压接管管线膨胀开裂原因分析

某低压乙二醇接管管线在运行过程中膨胀开裂。对爆管进行了宏微观检验、化学成分分析和厚度测试。结果表明，由于管段受到较大压力的作用，使管段产生较大的塑性变形，随着塑性变形的增大首先在接管焊缝热影响区的部位产生断裂破坏，最终导致爆管。提出了预防措施。