Results 81 to 90 of about 5,571 (162)

Fracture network complexity of tight sandstone and its influencing factors [PDF]

open access: yes
Objective  Fracture network analysis plays an important role in oil and gas exploration and development. However, complexity analysis of tight sandstone fracture networks and their control factors is relatively lagging.
FENG Xingqiang   +4 more
core   +1 more source

用于纳秒脉冲高压测量的同轴型电容分压器

open access: yesGaoya dianqi, 2008
阐述了电容分压器的电路原理,根据同轴型电容分压器的容值计算公式计算了电容分压器的理论分压比,研制了一种用于测量上升沿小于10 ns脉冲高压的同轴型电容分压器,并利用方波源和电阻分压器对其进行了标定。实验测试表明,该电容分压器满足测量要求,能很好地测量快前沿的陡脉冲电压信号。
刘轩东   +3 more
doaj  

Experimental study on grouting reinforcement characteristics of limestone with different length cracks under fluid solid coupling [PDF]

open access: yes
It is difficult to fully develop coal resources in the north of the Yellow River due to the influence of mine water disaster. Grouting technology is an important means to solve the problem of mine water disasters at present.
Dongxiu JIA   +4 more
core   +1 more source

Three-dimensional omnidirectional characterization methods of rock anisotropic wave velocity and acoustic emission location optimization [PDF]

open access: yes
Rock failure and instability have been key research topics in rock mechanics domestically and internationally. Numerous geotechnical disasters, such as rock bursts and slope instability, are associated with these phenomena. Acoustic emission detection is
Conghao LI   +5 more
core   +1 more source

Influence of resisted horizontal vibratility and stability ability to the reinforced concrete column by pre-stressing force [PDF]

open access: yes, 2009
针对普通钢筋混凝土柱抵抗水平性能较弱的特点,考虑在柱中布置一定数量的预应力筋并施加有效预应力来改善这一状况。本文对钢筋混凝土柱考虑预应力影响下的抗水平性能、稳定效应以及由此而构建的整体预应力混凝土框架结构的抗水平性能进行分析研究,主要工作及结论如下: (1)基于截面应变协调分析方法,经过分析推导得出钢筋混凝土柱考虑预应力影响下的水平荷载-位移求解公式,为分析钢筋混凝土柱抗水平性能提供了一定的理论依据。 (2)对钢筋混凝土柱考虑预应力影响下抗水平性能进行全过程非线性分析,研究了构件从开裂 ...
黄应江
core  

Subsection amplification cyclic deterioration mechanism of creep damaged coal [PDF]

open access: yes
Under the excavation effects of deep coal and rock, obvious creep damage is produced under the action of high stress for a long time and the sudden destabilization of the creep-damaged coal body induces rock burst disaster under the mining action in ...
Baotang SHEN   +5 more
core   +1 more source

残余应力对冷弯厚壁方矩管轴压承载力的影响

open access: yesJianzhu Gangjiegou Jinzhan, 2017
根据已有残余应力分布模型对冷弯厚壁型钢典型截面进行了理论分析,得到残余应力对冷弯厚壁型钢轴压构件承载力的影响规律。在理论分析的基础上对不同厚度、不同宽厚比的Q235、Q345冷弯厚壁型钢进行有限元分析,得到不同长细比的各构件在考虑和不考虑残余应力两种情况下的轴压承载力,并研究残余应力对冷弯厚壁型钢长柱轴压承载力的影响。结果表明:残余应力对冷弯厚壁型钢轴压承载力的影响在长细比为90时达到最大,且对Q235钢的影响比Q345钢的影响略小 ...
李元齐, 李功文, 沈祖炎
doaj  

Thermal and mechanical properties of fracture-filled granite with different structural forms under high temperature and high pressure [PDF]

open access: yes
The reservoir of deep hot dry rock (HDR) geothermal energy is not intact rock mass, which includes a large number of fractures induced by geological tectonic movement. The tectonic fractures are subsequently filled by hydrothermal fluid.
Weitao YIN, Zijun FENG
core   +1 more source

石油钻井工具用非标碟簧力学特性研究

open access: yesShiyou jixie, 2012
石油钻井工具常使用非标碟形弹簧缓冲振动,基于大变形弹塑性理论,使用有限元法分析了Φ118 mm非标碟簧在加载过程中的力学特性。分析结果表明,随碟簧压缩位移增加,Von Mises应力、周向应力、轴向应力、轴向变形量、周向变形量和厚度t轴向变形量呈非线性增大趋势。压缩位移小于2.5 mm时,碟簧未出现塑性变形;压缩位移为2.5 mm时,周向应力、轴向应力、轴向变形量和厚度t轴向变形量剧增,且碟簧发生塑性变形。对碟簧进行了刚度试验,压缩位移小于0.47 mm时碟簧刚度约为0.66 kN/mm,压缩位移大于0.
祝效华   +5 more
doaj  

Mechanical properties and energy evolution mechanism of coal prone to ejection [PDF]

open access: yes
In this paper, true triaxial loading and unloading tests under different principal stress conditions were conducted to study the mechanical properties, failure characteristics, and energy evolution laws of coal bodies that are prone to ejection under ...
Wentao XU, Yunhai CHENG
core   +1 more source

Home - About - Disclaimer - Privacy