共查询到19条相似文献,搜索用时 92 毫秒
1.
针对室内试验研究盘形滚刀破岩过程的成本高、周期长、不便于重复性教学演示的问题,可采用数值试验方法作为辅助或替代,揭示滚刀破岩机制、优化滚刀结构和切削参数。该文使用显式动力学数值方法,结合有限元和光滑粒子流体动力学,建立盘形滚刀切削岩石的三维数值试验模型,采用基于Rankine失效准则的摩尔-库伦弹塑性本构模型开展缩尺的滚刀线性切削试验,验证数值试验模型的可靠性。以双刀顺次回转破岩模型为例,分析了岩石破裂过程与滚刀载荷曲线。研究表明:在盘形滚刀切削下,岩石表面形成了条形破碎槽,同时在滚刀两侧及下方出现裂纹;随着裂纹延伸至岩石表面,许多小块的岩碴被剥离;使用数值试验方法分析盘形滚刀破岩过程,可以清晰地模拟密实核传力演化、裂纹萌生扩展、岩碴剥离飞溅、载荷阶跃波动等物理现象,有助于学生深入理解盘形滚刀破岩机制。 相似文献
2.
本文分析了高压变压器进行操作冲击试验的现状,提出用直流励磁法代替传统的操作冲击励磁法,有助于提高试验结果的准确性。 相似文献
3.
4.
5.
<正> 1 引言 目前国内外生产了少量的专用自动送样低温冲击试验机,按其操作规程可进行低温冲击试验,但多数厂矿和科研、学校的实验室在无此专用设备的情况下,可用常温冲击试验机运用简单的方法从事低温冲 相似文献
6.
高压断路器是高压供配电中最重要的一种电器.在电力系统设备中,就单台设备而言,断路器是仅次于发电机和变压器的大型供配电设备.断路器运行时完成的是倒换运行操作,把设备或线路接入电路或退出运行,起运行控制作用;当设备和线路发生故障时,断路器需要快速切除故障,保证无故障部分正常运行,起到运行保护功能.正是断路器在电力线路中负责控制和保护,所以,其机械性能和可靠性直接关系到电力系统的安全运行. 相似文献
7.
为了研究沥青混凝土的疲劳特性,提出了基于双线性内聚力模型(CZM)的数值模拟方法.建立了疲劳损伤演化模型并将其与内聚力模型耦合,以反映沥青混凝土在循环荷栽作用下的软化行为.通过编制用户材料子程序。实现了疲劳损伤模型在有限元软件ABAQUS中的应用,并对劈裂疲劳试验进行了模拟.研究结果表明:模拟得到的疲劳寿命与实验室结果基本一致;疲劳损伤随加载次数的累积是非线性的,且损伤累积阶段是疲劳破坏的主要阶段;应力比增大时,损伤稳态发展阶段的寿命明显减小.可以发现提出的疲劳损伤数值模型是一种预估沥青混凝土疲劳损伤的有效方法. 相似文献
8.
水射流与刀具联合破岩模型的有限元分析 总被引:2,自引:0,他引:2
本首先分析了在刀具(集中载荷)作用下,在煤岩体内所产生的应力场,并应用有限元分析软件模拟了岩体的力学模型,计算了不同截深下,使岩体破碎所需的最小刀具载荷,其次,建立了水射流与刀具联合破岩的力学模型,计算了三种岩体材料(无烟煤、软砂岩、玄武岩),在不同截深、不同裂纹深度和宽度下,作用一定压力的水射流后,使岩体破碎所需的最小刀具压力,并与机械破碎法进行了比较,得出联合破碎法优于单独的机械破碎法的结论。 相似文献
9.
10.
煤岩冲击倾向性试验及分析 总被引:1,自引:0,他引:1
利用MTS的特点和优势,对山东某矿现采煤层进行了煤岩冲击倾向性试验研究,通过对冲击能量指数、弹性能量指数和动态破坏时间三个煤层冲击能量指标的试验和分析,得出煤层具有较弱的冲击倾向;结合实际采矿条件,应加强冲击地压的预测预报,以保证矿井的安全生产。 相似文献
11.
邱贤德 《重庆大学学报(英文版)》2003,2(1)
1. Introduction In order to study rock damage and fragmentation during blasting, many numerical models have been developed. These efforts have varied from semi-empirical [1,2] to formulations based on shock wave physics [3,4]. Numerical modeling of blasting has been focusing on the complexity of the blasting process. This complexity requires that numerical models be developed in a highly systematic fashion in close coordination with controlled field and laboratory experimentation. This work d… 相似文献
12.
分析了先张法预应力混凝土波型板桩自身截面原形的力学性能,克服了以往将波形板桩截面等效简化为工字型截面的计算过程复杂繁琐且易产生误差的缺点,新的计算分析方法较以往等效截面计算方法更加科学合理,过程简单清晰,结果误差小。同时结合理论分析进行波型板桩抗弯和抗剪力学试验,对比理论计算结果与力学试验数据,两者吻合较好,验证了理论分析方法合理可靠。 相似文献
13.
The normal impingement process of two water droplets upon a thin film on the solid surface was numerically investigated. The numerical treatment was based on the finite volume solution of the Navier-Stokes (N-S) equations combined with the volume of fluid method (VOF). Physically reasonable results for the process of two droplets impacting on the thin film were obtained. The effects of the droplet velocity, the fihn thickness and the spacing between the two droplets on the splash and spread process of the impact were examined. 相似文献
14.
Dynamic response of RPC-filled steel tubular columns with high load carrying capacity under axial impact loading 总被引:3,自引:0,他引:3
Experimental investigation into impact-resistant behavior of reactive powder concrete (RPC)-filled steel tubular columns was conducted,and dynamic response of the columns under axial impact loading was studied by means of numerical simulation method.Increase coefficient of load carrying capacity and ratio of load carrying capacity between steel tube and RPC core of col-umns were obtained. 相似文献
15.
基于物理元胞自动机的岩石破坏模拟 总被引:1,自引:0,他引:1
为了分析岩石材料的非均质性对其破坏演化的影响,根据元胞自动机理论,从能量的角度建立了一种能够从细观层次上对岩石破坏演化进行模拟的物理元胞自动机模型(Mh-PCA模型),模型引用的Weibull随机分布函数对材料的非均质性进行描述.运用该模型,对m分别为1,5,10,15四种不同均质度材料的破坏模式及其破坏过程中的声发射现象进行了模拟分析.结果表明:材料的非均质性对其破坏有重要的影响,均质度越高,破坏过程中的分支裂纹越少,声发射也越集中.物理元胞自动机理论为岩石的破坏研究提供了一种新的研究思路. 相似文献
16.
17.
18.
Model test and numerical analysis on long-term mechanical properties of stepped reinforced retaining wall 总被引:1,自引:0,他引:1
Model tests and numerical analyses of stepped reinforced retaining wall were performed to investigate the effects of rheology of backfill and creep of geogrids on the long-term performance of the structure.The geogrid tensions,soil pressures,wall deformations and foundation pressure were measured during model construction and loading.A visco-elasto-plastic model and an empirical nonlinear visco-elastic model were utilized to simulate the stresses and deformations of geogrid-reinforced earth-retaining wall under long-term loads.By comparing test data with numerical results,it is shown that the foundation pressure distribution is nonlinear,and the lateral constraint of geogrids for backfill can cause a redistribution of foundation pressure.The curve of soil pressure is outside convex at each step initially,and it is close to the distribution for the case of vertical wall subsequently.The variation trend of geogrid tensions at different heights is obtained.Moreover,the failure mechanism and development mode of potential slip surface in retaining wall are proposed. 相似文献
19.
In tracking test,discharge is a complicated process and comparative tracking index(CTI)has wide variation.To evaluate tracking resistance,the chaos analysis of discharge current is presented based on the tracking test ofphenolic resin in accordance with IEC601 12.According to the characteristics of statistical self-similarity and complexity of discharge current,the largest Lyapunov exponent is calculated,and the 2-dimensional attractor ofdischarge current is reconstructed.Moreover,the attractors of discharge current and recurrence plots of different discharge states are reconstructed.The results indicate that the chaos attractors have different characteristics in evolutionary tracks,the topological structure and grain direction of recurrence plots show significant differences.The chaos attractor can describe the tracking process,the recurrence plot can identify the tracking state clearly,while its arithmetic is simple. 相似文献