Time filter

Source Type

Du J.-G.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Guo S.-X.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Chen P.,Luoyang Ship Material Research Institute | Guo Q.-L.,Dunhuang Academy | And 2 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2017

The wall-paintings of Mogao Grottoes have suffered from cracks initiated under the influence of external micro-vibration environment for a long time. Therefore, it is necessary to study the mechanism of crack initiation in the wall-paintings, which provides scientific basis and technical support for the wall-paintings protection and repair. Tensile strength is obtained by experiments of four-point bending on the plaster ground of the wall-paintings. Digital image correlation technique is used to measure the strain variation and distribution in real time. Besides, the crack initiation on the plaster ground is analyzed when tensile damage occurrs to obtain the strain limit of the wall-paintings. Moreover, the influences of initial flaw, loading method and fatigue cycle number on the bearing capacity and the strain limit of the specimen are studied. The results show that the initiation of cracks and even their development to some extent will not affect the bearing capacity of the grottoes wall structure. The initial flaw of the plaster ground can increase the risk of cracking around the flaw. Fibers such as hemp improve the plaster ground with better plasticity and durability, and reduce cracks within the fatigue limit. In order to avoid crack occurrence, maximum normal strain of the plaster ground should be strictly controlled less than 0.40%. © 2017, Science Press. All right reserved.


Shen J.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Zhang X.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Chen A.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Xu J.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Kong F.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Modern Tunnelling Technology | Year: 2014

Combined with model testing and numerical calculations, the propagation of an explosive stress wave in the surrounding rock of a proposed tunnel and the stability of an existing underground cavern were researched, and the relevant wave distribution law and displacement curve of the vault were obtained. The results show that: (1) the pressure peak decreases with an increase of distance from the explosion point; (2) the vertical pressure peak on the vertical measuring line through the explosion center is greater than the horizontal pressure peak in the same position through the centroid of the cavern, and the vertical pressure peak on the horizontal measuring line is greater than that of the horizontal pressure peak; (3) the pressure peak on the vault is less than the compressive strength of the lining, and moreover, the cavern is safe and stable without the unrecoverable displacement of the vault; and (4) attention should be focused on the dynamic response of the lining at the intersection of the cavern vault, arch foot, and sidewall crown during the blasting of a transportation tunnel. ©, 2014, Editorial Office of "Modern Tunnelling Technology". All right reserved.


Li L.-S.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Zhang H.-H.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Xie Q.-L.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Du J.-G.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

In order to investigate the failure pattern and threshold value of masonry wall under blast shock vibration loads, according to the practical situation of masonry wall in engineering, simplified masonry wall models were established. Experiments under the shock loads acting seperately in three directions were carried out on a shock testing machine for simulating the blast. The dynamic responses of the masonry wall models under the action of shock and vibration as well as the peak values and operation time of acceleration at the moment of failure were investigated. The results show that, for the masonry wall with bottom fixed and all-around constraint unconfined under the load of horizontal shock, the failure displays the form of horizontal straight joint damage. The failure is mainly caused by tensile stress instead of shearing stress. The failure threshold value under the shock loads acting seperately in three directions was obtained by analysis on the experimental results. ©, 2015, Chinese Vibration Engineering Society. All right reserved.


Li L.-S.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Du J.-G.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Zhang H.-H.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Xie Q.-L.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Baozha Yu Chongji/Explosion and Shock Waves | Year: 2015

The dynamic response of brick wall under blast shock vibration is very complex. it is difficult to establish its constitutive relation accurately. Several common finite-element methods to simulate brick wall were presented and merits and drawbacks of these method were analyzed. A three-dimensional finite-element model is applied in which the bricks and mortar are considered separatedly. LS-DYNA software is used to simulate the failure process of brick wall under horizontal blast shock vibration and the results were agreed well with the experiment. The research indicates that the analytical model considers the complex interaction of brick and mortar integratedly and the mortar layer is modeled separately which ensured the validity and correctness of the numerical simulation, so the accumulative damage of the mortar layer between the bricks in the experiment could be simulated accurately. ©, 2015, Explosion and Shock Waves. All right reserved.


Wu J.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Yang Y.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Zhuang T.-S.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Zhuang T.-S.,PLA University of Science and Technology
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2016

To further reveal the action mechanism and damage effect characteristics of underwater explosion, the progresses of study on the action mechanism and damage effect of underwater explosion were systematically reviewed from six aspects as mechanism, shock wave propagation, bubble pulsation, damage effect and dynamic response of structure, test technology and numerical simulation and damage assessment for underwater explosion of different explosives. Some key technical problems which should be investigated or solved in future including energy release and diffusion of the underwater explosion of non-ideal explosive, damage of coupling action of shock wave and air bubble to structure and damage assessment methods for underwater explosion, multi-scale simulation technology for underwater explosion were proposed. © 2016, Editorial Board of Journal of Explosives & Propellants. All right reserved.


Yu S.-J.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Chen X.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Yang J.-X.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2011

In order to measure the dynamic strain in concrete in impact or explosive test, a fiber Bragg grating (FBG) sensor specially designed for inner strain measurement in concrete was developed. The concrete specimens in which the FBG sensors were embedded were prepared and tested under impact on split Hopkinson pressure bar (SHPB). The inner and surface strains were measured by FBG sensors and strain gauges separately and an attempt to construct the dynamic relationship between stress and strain with the data was made. The analyses of the results show that the method of strain measurement in concrete with embedded FBG sensors is feasible and more reasonable if the measurements of accurate strains and exact performance of concrete are demanded. The FBG sensors were proved to be suitable for dynamic strain measurement in concrete and can be widely used in concrete and rock in their dynamic performance tests and response measurements under impact or explosive loads.


Zai J.-M.,Hefei University of Technology | Zai J.-M.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Wang S.-H.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Li Y.-C.,Hefei University of Technology | Yang J.-M.,Hefei University of Technology
Jisuan Lixue Xuebao/Chinese Journal of Computational Mechanics | Year: 2010

Numerical simulation has been conducted on the propagation of the explosion wave on the primary-secondary basis in an axisymmetric tube with varying cross section, using the MUSCL with second-order precision, the non-structural, self-adaptable mesh technique, and the finite volume form. The results show that the shock wave flow field is uniform and steady with good waveform when the explosion wave on the primary-secondary basis runs into the target region. Desired overpressure and duration of the shock wave could be obtained if the explosive energy of the driver section is properly increased.


Wang S.-H.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Ren H.-Q.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Li L.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Baozha Yu Chongji/Explosion and Shock Waves | Year: 2013

To overcome the difficulties in measuring the chamber pressure, which resulting from the instantaneous high temperature, high pressure and strong shake produced by TNT explosion, two methods were applied to measure the chamber pressure by installing pressure sensors on the wall of the cylindrical explosion containment vessel and setting a DT-FDCYG storage-type electronic pressure-measuring apparatus in the vessel, respectively. After the experiments, all the pressure sensors installed on the wall of the vessel were damaged, while the intact waveform was obtained by the electronic pressure-measuring apparatus, the chamber-pressure peaks of which were discrete. The experimental data are helpful for the design of large explosion equipments.


Wu B.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Yang J.-C.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Liu R.-C.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Baozha Yu Chongji/Explosion and Shock Waves | Year: 2013

Four kinds of finite thickness target plates were prepared, including granite (G) plates, steel wire-mesh reinforced concrete (RC) plates, composite GRC targets composed by granite (G) plates and steel wire-mesh reinforced concrete (RC) plates, and composite GBRC targets composed by granite block (GB) masonry and steel wire-mesh reinforced concrete (RC) plates. By using a 30-mm-caliber gun to accelerate two kinds of projectiles of the same shape which differ in material strength, penetration experiments were carried out for these prepared target plates, respectively. The damage effects of the target plates subjected to projectile penetration were compared. The results show that the well-designed GBRC targets have the best resistance to perforation. And the perforation resistance of the GBRC targets is closely related with the following factors: block stone size, strength, masonry way, and reinforced concrete structure.


Ding X.-B.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Ding X.-B.,Harbin Institute of Technology | Zhang C.,Henan University of Science and Technology | Ming Z.-Q.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff | Xu J.-M.,The Third Engineer Scientific Research Institute of the Headquarters of the General Staff
Yantu Lixue/Rock and Soil Mechanics | Year: 2013

In large-scale geomechanical model, because of the fragility and low strength of similar model material, it is difficult to get its complete bending stress-strain curve or load-displacement curve. This paper performed mechanical analysis on the bending experiment process, and got the stiffness designing principle of elastic element through some derivation for the solution of increasing the auxiliary elastic element. Based on this principle, we assembled a test prototype and obtained complete bending load-displacement curves for the specimens with different joints (homogeneous, layered and massive) containing different angles bolt. In addition, the dead weight of specimen was considered in the experiment due to the similar material's characteristics of low strength and bulk density. Experimental studies have shown that, the increasement of elastic element has a noteworthy improvement for the decreasing segment of the complete bending load-displacement curve. When the composite stiffness of the elastic element and prototype system is greater than the maximum stiffness of the specimen, the curve can be measured. The dead weight of specimen can be equivalent to the concentrated force in the bending experiment, and the equivalent load for the 550 mm long Standard specimen is 50% of its own weight or 9% of the peak load in homogeneous specimen's experiment.

Loading The Third Engineer Scientific Research Institute of the Headquarters of the General Staff collaborators
Loading The Third Engineer Scientific Research Institute of the Headquarters of the General Staff collaborators