侵彻过程中弹载测试装置防护技术研究及仿真

复杂的侵彻动力学环境对测试系统安全可靠的工作产生巨大威胁,为了可靠的完成测试任务,文中叙述了弹载测试装置抗高过载冲击的防护措施和缓冲机理,对简单的弹性静力学缓冲模型进行了分析.利用有限元软件ANSYS/LSDYNA对内置测试装置的卵形空心弹体侵彻钢靶进行了数值模拟.同时结合橡胶的特性对防护技术进行了仿真研究.     

Effect of distance from the support on the penetration mechanism of clamped circular polycarbonate armor plates

A 1.91-mm thick circular polycarbonate plate of 115 mm diameter was impacted by a spherical steel projectile of 6.98 mm diameter at its center. Subsequent impacts were made at 10, 20, 30, 40, and 50 mm radii of the plate. Dent dimensions for the damaged plate were measured using optical microscope. For a constant projectile velocity of 138 m s⁻¹ which was below the perforation limit of the plate under investigation, a maximum thickness reduction close to the edge support was observed. The experimental work was modeled into explicit finite-element analysis program LSDYNA for simulations. LSDYNA was able to predict the dent depth and reduction in plate thickness at impact points precisely. In this research, the effect of the impact location distance from the supports on the damage mechanism of circular polycarbonate armor plates is investigated. The target plate was subjected to constant velocity projectile impacts starting at the plate midpoint and varying the impact distance from midpoint towards the clamped edge. Failure of plate is predicted close to the constrained boundary under uniform conditions.     

含硫结块矿石诱导崩落分解特性分析

针对铜坑矿矿石结块问题,运用爆破放顶技术,诱导结块矿石的自然崩落分解。以结块矿石为研究对象,利用LSDYNA数值软件对不同跌落角度、跌落高度和弱结构参数条件下的跌落过程进行仿真模拟试验,获得了结块矿石的崩落分解规律,提出了相应的诱导崩落技术参数。研究结果表明：①结块矿石在跌落高度为5 m和崩落角度30°时能够获得很好的崩解效果,崩解率达到100%。②结块矿石与触地接触面的高度应不小于5 m,并且诱导爆破超深面与水平形成的夹角θ需满足5°＜θ＜30°。研究结果为实施诱导破碎结块矿石的技术工艺和参数提供了理论依据。     

安全气囊的数值分析方法研究

基于LSDYNA软件研究了安全气囊的数学模型、材料及单元的选取,利用其相应数值模拟结果为分析气囊的折叠方式、气囊对fKA-的作用效果及选材选取提供理论依据.     

Lateral collapse of short‐length sandwich tubes compressed by different indenters and exposed to external constraints

In this paper, sandwich tube components which consist of thin‐walled circular tubes with aluminium foam core are proposed as energy absorption systems. The sandwich tubes were laterally crushed under quasi‐static loading conditions. The sandwich tubes were crushed under two types of indenters and exposed to three different types of external constraints. The collapsing behaviour and the energy absorption responses of these systems were investigated by nonlinear finite element analysis through ANSYS‐LS‐DYNA. Various indicators which describe the effectiveness of energy absorbing systems were used as a marker to compare the various systems. It was found that the sandwich tube systems compressed by cylindrical indenters particularly the unconstrained system and the system with inclined constraints offered a very desirable force‐deflection in which the force is almost constant in the post collapse stage. The employing of external constraints was noticed as a feasible method of increasing the SEA particularly when cylindrical indenter is used.     

Impact resistance of a rectangular polycarbonate armor plate subjected to single and multiple impacts

In the present work the plastic deformation of a thin rectangular polycarbonate armor plate subjected to single and multiple impacts was investigated in detail. The impacts were conducted on a horizontal and diagonal path to explore the plate vulnerability against the in-coming single and multiple projectiles striking at various locations. Single impacts revealed the overall trend in plate dent sizes and thickness reductions on the horizontal and diagonal paths. Results were compared with previous research [Shah QH, Abakr YA. Effect of distance from the support on the penetration mechanism of clamped circular polycarbonate armor plates. International Journal of Impact Engineering 2008;35:1244–50] conducted on circular armor plate for validation purposes. The single impact data scatter necessitated to conduct repeated impact tests at reduced number of locations to search for a definite answer for the possible failure process in the vicinity of the clamped edges of the plate. An accelerated plastic deformation resulting in early perforation was found to occur in the diagonal plate corner compared to the plate center impact position or close to a straight clamped edge. Multiple impact results presented can be significantly helpful in designing rectangular shape polycarbonate armor plates to enhance safety. LSDYNA was used to simulate the impact event for the plate midpoint, the horizontal edge, and the diagonal edge. The results show a close agreement with the experimental work.     

有限元技术在手机概念设计中的应用

为有效发现手机壳体的设计缺陷,运用HyperMesh和LS-DYNA软件仿真手机自由跌落,分析不同圆角半径的设计对手机壳体强度和刚度的影响.仿真和分析结果可以为手机壳体圆角半径设计提供参考.     

大圆钢轧制三维塑性变形有限元模拟

使用ANSYS/LS-DYNA通用有限元分析软件对大圆钢轧制过程进行了模拟仿真,得到了采用单圆弧成品前椭圆孔型的大圆钢轧制的等效应力场、等效应变场,分析了轧件横截面的等效应变和等效应力分布情况.成品前孔型改为双圆弧椭圆孔型后重新模拟轧制过程,把模拟结果进行比较,得出采用双圆弧成品前椭圆孔型有利于改善成品道次的应力、应变分布.     

带钢表面氧化层湿式抛丸清理技术

目前绝大部分钢铁公司带钢表面氧化层的清理主要通过酸洗工艺或干式抛丸设备,然而这些表面处理工艺存在污染环境,过酸洗,灰尘、弹丸分离效果差,带钢表面划痕明显等问题。文中分析、整合了抛丸和喷丸技术的环境污染小,带钢表面无划痕,抛丸参数可控、易调节,不会过清理等优点,在常规抛丸设备中引入水系统,提出了一种湿式抛丸处理工艺,开发了一台湿式抛丸设备。通过PLC及触摸屏人机控制,完成了抛丸设备抛丸器,带钢移动小车,斗式提升机等不同部件的协调运动。利用有限元软件ANSYS/LSDYNA进行动力学仿真,分析并优化了抛丸参数对带钢表面性能的影响关系。试验表明,湿式抛丸可以有效清除带钢表面氧化层,并且与酸洗和干式抛丸相比,有一定的优越性。