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Effect of Blasting Stress Wave on Dynamic Crack Propagation
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作者 Huizhen Liu Duanying Wan +2 位作者 Meng Wang Zheming Zhu Liyun Yang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期349-368,共20页
Stress waves affect the stress field at the crack tip and dominate the dynamic crack propagation.Therefore,evaluating the influence of blasting stress waves on the crack propagation behavior and the mechanical charact... Stress waves affect the stress field at the crack tip and dominate the dynamic crack propagation.Therefore,evaluating the influence of blasting stress waves on the crack propagation behavior and the mechanical characteristics of crack propagation is of great significance for engineering blasting.In this study,ANSYS/LS-DYNA was used for blasting numerical simulation,in which the propagation characteristics of blasting stress waves and stress field distribution at the crack tip were closely observed.Moreover,ABAQUS was applied for simulating the crack propagation path and calculating dynamic stress intensity factors(DSIFs).The universal function was calculated by the fractalmethod.The results show that:the compressive wave causes the crack to close and the reflected tensile wave drives the crack to initiate and propagate,and failure mode is mainly tensile failure.The crack propagation velocity varies with time,which increases at first and then decreases,and the crack arrest occurs due to the attenuation of stress waves and dissipation of the blasting energy.In addition,crack arrest toughness is smaller than the crack initiation toughness,applied pressure waveforms(such as the peak pressure,duration,waveforms,wavelengths and loading rates)have a great influence on DSIFs.It is conducive to our deep understanding or the study of blasting stress waves dominated fracture,suggesting a broad reference for the further development of rock blasting in engineering practice. 展开更多
关键词 Crack propagation blasting stress wave dynamic stress intensity factor pressure waveform numerical simulation
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Macro Meso Response and Stress Wave Propagation Characteristics of MCT High-Voltage Switch Under Shock load
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作者 Yuyang Guo Chuang Chen +1 位作者 Ruizhi Wang Enling Tang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期317-335,共19页
In order to study the dynamic and electrical coupling response characteristics of Metal Oxide Semiconductor Controlled Thyristor(MCT)high-voltage switch under the synergic action of mechanical load and high voltage,th... In order to study the dynamic and electrical coupling response characteristics of Metal Oxide Semiconductor Controlled Thyristor(MCT)high-voltage switch under the synergic action of mechanical load and high voltage,the separated Hopkinson pressure bar(SHPB)test system was used to simulate different impact load environments,and combined with the multi-layer high-voltage ceramic capacitor charging and discharging system,the instantaneous electrical signals of MCT high-voltage switch were collected.Combined with numerical simulation and theoretical analysis,the failure mode and stress wave propagation characteristics of MCT high voltage switch were determined.The mechanical and electrical coupling response characteristics and failure mechanism of MCT high voltage switch under dynamic load were revealed from macroscopic and microscopic levels.The results show that the damage modes of MCT high-voltage switches can be divided into non-functional damage,recoverable functional damage,non-recoverable damage and structural damage.Due to the gap between the metal gate and the oxide layer,the insulating oxide layer was charged.After placing for a period of time,the elastic deformation of the metal gate partially recovered and the accumulated charge disappeared,which induced the recoverable functional damage failure of the device.In addition,obvious cracks appeared on both sides of the monocrystalline silicon inside the MCT high-voltage switch,leading to unrecoverable damage of the device. 展开更多
关键词 MCT Impact load Failure analysis stress wave Numerical simulation
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Non-dimensional analysis on blast wave propagation in foam concrete:Minimum thickness to avoid stress enhancement
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作者 Ya Yang Xiangzhen Kong Qin Fang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第6期30-46,共17页
Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress miti... Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage.However,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load.To investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method.The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement.The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are considered.In particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed.Finally,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering. 展开更多
关键词 Foam concrete Blast wave propagation Non-dimensional analysis stress enhancement
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Isolated Hyperacute T-Waves in West Nile Encephalitis Indicating Atypical Variant of Stress-Induced Cardiomyopathy
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作者 Soomal Rafique Nadeem Khan Momin Siddique 《Journal of Biosciences and Medicines》 2024年第2期303-310,共8页
Several cardiac outcomes have been reported with West Nile-encephalitis;however, the underlying pathophysiology remains complex. We present a 42-year-old female, with multiple sclerosis, whose neurological symptoms an... Several cardiac outcomes have been reported with West Nile-encephalitis;however, the underlying pathophysiology remains complex. We present a 42-year-old female, with multiple sclerosis, whose neurological symptoms and respiratory decline were finally explained by the diagnosis of West Nile-encephalitis. During her admission, the isolated peaked T-waves indicated the underlying stress-induced cardiomyopathy. The absence of all other causes of hyperacute T-waves, their subsequent resolution with the resolution of infection and improvement in wall motion abnormalities, further supported the association. This case highlights the importance of considering hyperacute T-waves in an approach towards the diagnosis of WNV-encephalitis related atypical variant of stress-induced cardiomyopathy. 展开更多
关键词 West Nile Virus encephalitis WNV Hyperacute T-waves Takotsubo Cardiomyopathy Atypical/Inverted Variant of stress-Induced Cardiomyopathy CMP
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Application of Nonlinear Lamb Wave Mixing Method for Residual Stress Measurement in Metal Plate 被引量:1
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作者 Jingpin Jiao Li Li +3 位作者 Xiang Gao Quan Cheng Cunfu He Bin Wu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第1期211-223,共13页
Harmonic nonlinear ultrasound can offer high sensitivity for residual stress measurements;however,it cannot be used for local stress measurements at a point in space and exhibits nonlinear distortions in the experimen... Harmonic nonlinear ultrasound can offer high sensitivity for residual stress measurements;however,it cannot be used for local stress measurements at a point in space and exhibits nonlinear distortions in the experimental system.This paper presents a feasibility study on the measurement of residual stress in a metal plate using a nonlinear Lamb wave-mixing technique.The resonant conditions for two Lamb waves to generate a mixing frequency wave are obtained via theoretical analysis.Finite element simulations are performed to investigate the nonlinear interactions between the two Lamb waves.Results show that two incident A0 waves interact in regions of material nonlinearity and generate a rightward S0 wave at the sum frequency.Residual stress measurement experiments are conducted on steel plate specimens using the collinear Lamb wave-mixing technique.By setting different delays for two transmitters,the generated sum-frequency component at different spatial locations is measured.Experimental results show that the spatial distribution of the amplitude of the sum-frequency component agrees well with the spatial distribution of the residual stress measured using X-rays.The proposed collinear Lamb wave-mixing method is effective for measuring the distribution of residual stress in metal plates. 展开更多
关键词 Residual stress Lamb wave Collinear wave mixing Nondestructive testing Resonant conditions
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Stress wave analysis of high-voltage pulse discharge rock fragmentation based on plasma channel impedance model 被引量:1
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作者 黄仕杰 刘毅 +5 位作者 赵勇 徐尤来 林福昌 李化 张钦 李柳霞 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第6期52-64,共13页
High-voltage pulse discharge(HVPD)rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters,electrode type,etc.In this work,an HVPD rock fragmentation test platform wa... High-voltage pulse discharge(HVPD)rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters,electrode type,etc.In this work,an HVPD rock fragmentation test platform was built and the test waveforms were measured.Considering the effects of temperature,channel expansion and electromagnetic radiation,the impedance model of the plasma channel in the rock was established.The parameters and initial values of the model were determined by an iterative computational process.The model calculation results can reasonably characterize the development of the plasma channel in the rock and estimate the shock wave characteristics.Based on the plasma channel impedance model,the temporal and spatial distribution characteristics of the radial stress and tangential stress in the rock were calculated,and the rock fragmentation effect of the HVPD was analyzed. 展开更多
关键词 stress wave shock wave plasma channel impedance model rock fragmentation high-voltage pulse discharge
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Deformation and Stress Analysis of the Deepwater Steel Lazy Wave Riser Subjected to Internal Solitary Waves 被引量:1
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作者 LI Fuheng GUO Haiyan +2 位作者 GU Honglu LIU Zhen LI Xiaomin 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第2期377-392,共16页
The dynamic response of the steel lazy wave riser(SLWR)subjected to the internal solitary wave is a key to assessing its application feasibility.The innovation of this paper is to study the dynamic response properties... The dynamic response of the steel lazy wave riser(SLWR)subjected to the internal solitary wave is a key to assessing its application feasibility.The innovation of this paper is to study the dynamic response properties of the SLWR with large deformation characteristics under internal wave excitation.A numerical scheme of the SLWR is constructed using the slender-rod theory,and the internal solitary wave(ISW)with a two-layer seawater model is simulated by the extended Korteweg-deVries equation.The finite element method combined with the Newmark-βmethod is applied to discretize the equations and update the time integration.The ISW excitation combined with vessel motion on the dynamic deformation and stress of the SLWR is investigated,and extensive simulations of the ISW parameters,including the interface depth ratio and density difference,are carried out.Case calculation reveals that the displacement of the riser in the lower interface layer increases significantly under the ISW excitation,and the stresses at a part of both ends grow evidently.Moreover,the mean value of riser responses under a combination of vessel motion and ISW coincides with the ISW-induced ones.Furthermore,the dynamic responses along the whole riser,including the displacement amplitudes,bending moment amplitudes,and stress amplitudes,almost increase with the increase in interface depth ratios and density differences. 展开更多
关键词 steel lazy wave riser(SLWR) internal solitary wave(ISW) slender-rod theory DEFORMATION stress
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Improving tree health assessment accuracy at low temperatures:considering the effect of trunk ice content on electrical resistance and stress wave tomography
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作者 Jiaxing Guo Peng Wang +1 位作者 Yuting Wang Huadong Xu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第5期1503-1510,共8页
Accurate decay detection and health assessment of trees at low temperatures is an important issue for forest management and ecology in cold areas.Low temperature ice formation on tree health assessment is unknown.Beca... Accurate decay detection and health assessment of trees at low temperatures is an important issue for forest management and ecology in cold areas.Low temperature ice formation on tree health assessment is unknown.Because electric resistance tomography and stress wave tomography are two widely used methods for the detection of tree decay,this study investigated the effect of ice content on trunk electrical resistance and stress wave velocity to improve tree health assessment accuracy.Moisture content,trunk electrical resistance and stress wave velocity using time domain reflectometry were carried out on Larix gmelinii and Populus simonii.Ice content is based on moisture content data.The ice content of both species showed a trend of increasing and then decreasing.This was opposite with ambient temperatures.With the decrease of temperatures,daily average ice content increased,but the range narrowed gradually and both electrical resistance and stress wave velocity increased.Both increased rapidly near 0℃,mainly caused by ice formation(phase change and freezing of free water)in live trees.In addition,both are positively correlated with ice content.The results suggest that ice content should be considered for improving the accuracy of tree decay detection and health evaluation using electric resistance tomography and stress wave velocity methods under low temperatures. 展开更多
关键词 Cross-section electrical resistance Cross-section stress wave velocity Ambient temperatures Ice content Wood decay detection Tree heath
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Blasting induced dynamic stress concentration and failure characteristics of deep-buried rock tunnel
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作者 ZHAO Rui TAO Ming +2 位作者 XIANG Gong-liang WANG Shao-feng ZHAO Hua-tao 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2321-2340,共20页
In this study,the dynamic stress concentration factors(DSCF)around a straight-wall arch tunnel(SWAT)were solved analytically utilizing the complex variable function methods and Duhamel’s integral.The effects of wavel... In this study,the dynamic stress concentration factors(DSCF)around a straight-wall arch tunnel(SWAT)were solved analytically utilizing the complex variable function methods and Duhamel’s integral.The effects of wavelength,incident angle,and blasting rising time on the DSCF distribution were analyzed.Theoretical results pointed out dynamic disturbances resulting in compressive stress concentration in the vertical direction and tensile stress in the incident direction.As the wavelength and rising time increased,there was a tendency for the amplitude of stress concentration to initially rise and then converge.Moreover,a series of 3D FEM models were established to evaluate the effect of different initial stress states on the dynamic failure of the tunnel surrounding rock.The results indicated that the failure of the surrounding rock was significantly influenced by the direction of the static maximum principal stress and the direction of the dynamic disturbance.Under the coupling of static and blasting loading,damage around the tunnel was more prone to occur in the dynamic and static stress concentration coincidence zone.Finally,the damage modes of rock tunnel under static stress and blasting disturbance from different directions were summarized and a proposed support system was presented.The results reveal the mechanisms of deep-buried rock tunnel destruction and dynamically triggered rockburst. 展开更多
关键词 stress wave scattering dynamic stress analysis rock tunnel dynamic failure analysis
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Analytical solutions of turbulent boundary layer beneath forward-leaning waves
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作者 Yiqin XIE Jifu ZHOU +3 位作者 Xu WANG Jinlong DUAN Yongjun LU Shouqian LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第4期695-710,共16页
As a typical nonlinear wave,forward-leaning waves can be frequently encountered in the near-shore areas,which can impact coastal sediment transport significantly.Hence,it is of significance to describe the characteris... As a typical nonlinear wave,forward-leaning waves can be frequently encountered in the near-shore areas,which can impact coastal sediment transport significantly.Hence,it is of significance to describe the characteristics of the boundary layer beneath forward-leaning waves accurately,especially for the turbulent boundary layer.In this work,the linearized turbulent boundary layer model with a linear turbulent viscosity coefficient is applied,and the novel expression of the near-bed orbital velocity that has been worked out by the authors for forward-leaning waves of arbitrary forward-leaning degrees is further used to specify the free stream boundary condition of the bottom boundary layer.Then,a variable transformation is found so as to make the equation of the turbulent boundary layer model be solved analytically through a modified Bessel function.Consequently,an explicit analytical solution of the turbulent boundary layer beneath forward-leaning waves is derived by means of variable separation and variable transformation.The analytical solutions of the velocity profile and bottom shear stress of the turbulent boundary layer beneath forward-leaning waves are verified by comparing the present analytical results with typical experimental data available in the previous literature. 展开更多
关键词 forward-leaning wave turbulent boundary layer velocity profile bottom shear stress
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Evaluation of the coefficient of lateral stress at rest of granular materials under repetitive loading conditions
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作者 Heerym Han Hyunwook Choo Junghee Park 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1709-1721,共13页
Although the internal stress state of soils can be affected by repetitive loading,there are few studies evaluating the lateral stress(or K_(0))of soils under repetitive loading.This study investigates the changes in K... Although the internal stress state of soils can be affected by repetitive loading,there are few studies evaluating the lateral stress(or K_(0))of soils under repetitive loading.This study investigates the changes in K_(0) and directional shear wave velocity(V_(s))in samples of two granular materials with different particle shapes during repetitive loading.A modified oedometer cell equipped with bender elements and a diaphragm transducer was developed to measure the variations in the lateral stress and the shear wave velocity,under repetitive loading on the loading and unloading paths.The study produced the following results:(1)Repetitive loading on the loading path resulted in an increase in the K_(0) of test samples as a function of cyclic loading number(i),and(2)Repetitive loading on the unloading path resulted in a decrease in K_(0) according to i.The shear wave velocity ratio(i.e.V_(s)(HH)/V_(s)(VH),where the first and second letters in parentheses corresponds to the directions of wave propagation and particle motion,respectively,and V and H corresponds to the vertical and horizontal directions,respectively)according to i supports the experimental observations of this study.However,when the tested material was in lightly over-consolidated state,there was an increase in K_(0) during repetitive loading,indicating that it was the initial K_(0),rather than the loading path,which is responsible for the change in K_(0).The power model can capture the variation in the K_(0) of samples according to i.Notably,the K_(0)=1 line acts as the boundary between the increase and decrease in K_(0) under repetitive loading. 展开更多
关键词 Coefficient of lateral stress at rest Repetitive loading Granular materials Shear wave velocity Stiffness anisotropy
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Assessment of Calf Skeletal Muscle Stiffness in Diabetic Nephropathy Patients with Medial Tibial Stress Syndrome by Two-Dimensional Shear Wave Elastography
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作者 Lei Wang Lei Ran 《Proceedings of Anticancer Research》 2023年第5期11-16,共6页
Objective:To explore the feasibility of two-dimensional shear wave elastography in evaluating calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome.Methods:A total of 48 di... Objective:To explore the feasibility of two-dimensional shear wave elastography in evaluating calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome.Methods:A total of 48 diabetic nephropathy patients with medial tibial stress syndrome from January 2020 to December 2022 were included as the study group,and 48 patients with diabetic nephropathy during the same period were included as the control group.Both groups were detected by two-dimensional shear wave elastography with ultrasonic equipment,and Young‘s modulus of the tibialis anterior muscle,tibialis posterior muscle,and gastrocnemius muscle were observed and analyzed in the two groups.Results:The Young‘s modulus values of tibialis anterior muscle,tibialis posterior muscle,and gastrocnemius muscle in the study group were significantly lower than those in the control group(P<0.05).Conclusion:Two-dimensional shear wave elastography is feasible for the evaluation of calf skeletal muscle stiffness in diabetic nephropathy patients with medial tibial stress syndrome,and has high accuracy and repeatability.This technique can be used to diagnose,treat and monitor muscle lesions in patients with diabetic nephropathy,and can also be used to assess muscle fatigue and exercise capacity,which has broad application prospects. 展开更多
关键词 Two-dimensional shear wave elastography Diabetic nephropathy Medial tibial stress syndrome
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Pilot study on the effect of flavonoids on arterial stiffness and oxidative stress in chronic kidney disease
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作者 Anastasia Vagopoulou Panagiotis Theofilis +4 位作者 Despina Karasavvidou Nasra Haddad Dimitris Makridis Stergios Tzimikas Rigas Kalaitzidis 《World Journal of Nephrology》 2024年第3期41-48,共8页
BACKGROUND Flavonoids,the main class of polyphenols,exhibit antioxidant and antihypertensive properties.AIM To prospectively investigate the impact of flavonoids on arterial stiffness in patients with chronic kidney d... BACKGROUND Flavonoids,the main class of polyphenols,exhibit antioxidant and antihypertensive properties.AIM To prospectively investigate the impact of flavonoids on arterial stiffness in patients with chronic kidney disease(CKD)stagesⅠ-Ⅳ.METHODS In this prospective,single-arm study,CKD patients with arterial hypertension and diabetes mellitus were enrolled.Baseline demographic,clinical,and laboratory variables were recorded.Patients received daily treatment with a phenol-rich dietary supplement for 3 months.Blood pressure,arterial stiffness(carotidfemoral pulse wave velocity,central pulse pressure),and oxidative stress markers(protein carbonyls,total phenolic compound,total antioxidant capacity)were measured at baseline and at study end.RESULTS Sixteen patients(mean age:62.5 years,87.5%male)completed the study.Following intervention,peripheral systolic blood pressure decreased significantly by 14 mmHg(P<0.001).Carotid-femoral pulse wave velocity decreased from 8.9 m/s(baseline)to 8.2 m/s(study end)(P<0.001),and central pulse pressure improved from 59 mmHg to 48 mmHg(P=0.003).Flavonoids also reduced oxidative stress markers including protein carbonyls(P<0.001),total phenolic compound(P=0.001),and total antioxidant capacity(P=0.013).CONCLUSION Flavonoid supplementation in CKD patients shows promise in improving blood pressure,arterial stiffness,and oxidative stress markers. 展开更多
关键词 FLAVONOIDS Chronic kidney disease Arterial stiffness Oxidative stress Carotid-femoral pulse wave velocity
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Dynamic Stress Intensity Factor and Scattering of SH Wave by Circle Canyon and Crack
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作者 任云燕 韩峰 史守峡 《Journal of Beijing Institute of Technology》 EI CAS 2000年第3期255-261,共7页
The dynamic stress intensity factor (DSIF) and the scattering of SH wave by circle canyon and crack are studied with Green's function. In order to solve the problem, a suitable Green's function is constructed... The dynamic stress intensity factor (DSIF) and the scattering of SH wave by circle canyon and crack are studied with Green's function. In order to solve the problem, a suitable Green's function is constructed first, which is the solution of displacement fields for elastic half space with circle canyon under output plane harmonic line loading at horizontal surface. Then the integral equation for determining the unknown forces in the problem can be changed into the algebraic one and solved numerically so that crack DSIF can be determined. Last when the medium parameters are altered, the influence on the crack DSIF is discussed partially with the displacement between circle canyon and crack. 展开更多
关键词 circle canyon and crack scattering of SH wave integral equation dynamic stress intensity factor (DSIF)
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SCATTERING OF FLEXURAL WAVES AND DYNAMIC STRESS CONCENTRATIONS IN MINDLIN'S THICK PLATES WITH A CUTOUT 被引量:16
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作者 刘殿魁 胡超 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1996年第2期169-185,共17页
Using the complex variable method and conformal mapping,scat- tering of flexural waves and dynamic stress concentrations in Mindlin's thick plates with a cutout have been studied.The general solution of the stress... Using the complex variable method and conformal mapping,scat- tering of flexural waves and dynamic stress concentrations in Mindlin's thick plates with a cutout have been studied.The general solution of the stress problem of the thick plate satisfying the boundary conditions on the contour of cutouts is obtained. Applying the orthogonal function expansion technique,the dynamic stress problem can be reduced into the solution of a set of infinite algebraic equations.As examples, numerical results for the dynamic stress concentration factor in Mindlin's plates with a circular,elliptic cutout are graphically presented in sequence. 展开更多
关键词 Mindlin's thick plate scattering of flexural waves dynamic stress concentration complex variable method
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Effect of sensor quantity on measurement accuracy of log inner defects by using stress wave 被引量:10
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作者 WANG Li-hai XU Hua-dong ZHOU Ci-lin LI Li YANG Xue-chun 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第3期221-225,共5页
Wood nondestructive testing (NDT) is one of the high efficient methods in utilizing wood. This paper explained the principle of log defect testing by using stress wave, and analyzed the effects of sensor quantity on... Wood nondestructive testing (NDT) is one of the high efficient methods in utilizing wood. This paper explained the principle of log defect testing by using stress wave, and analyzed the effects of sensor quantity on defect testing results by using stress wave in terms of image fitting degree and error rate. The results showed that for logs with diameter ranging from 20 to 40 cm, at least 12 sensors were needed to meet the requirement which ensure a high testing accuracy of roughly 90% of fitness with 0.1 of error rate. And 10 sensors were recommended to judge the possible locations of defects and 6 sensors were sufficient to decide whether there were defects or not. 展开更多
关键词 Sensor quantity Log defect testing stress wave Image fitting degree
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PROPAGATION OF LOVE WAVES IN PRESTRESSED PIEZOELECTRIC LAYERED STRUCTURES LOADED WITH VISCOUS LIQUID 被引量:7
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作者 Jianke Du Kai Xian +1 位作者 Ji Wang Yook-Kong Yong 《Acta Mechanica Solida Sinica》 SCIE EI 2008年第6期542-548,共7页
We investigate analytically the effect of initial stress in piezoelectric layered structures loaded with viscous liquid on the dispersive and attenuated characteristics of Love waves, which involves a thin piezoelectr... We investigate analytically the effect of initial stress in piezoelectric layered structures loaded with viscous liquid on the dispersive and attenuated characteristics of Love waves, which involves a thin piezoelectric layer bonded perfectly to an unbounded elastic substrate. The effects of initial stress in the piezoelectric layer and the viscous coefficient of the liquid on the phase velocity of Love waves are analyzed. Numerical results are presented and discussed. The analytical method and the results can be useful for the design of chemical and biosensing liquid sensors. 展开更多
关键词 Love waves PIEZOELECTRIC viscous liquid initial stress
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Theoretical analysis of JMC effect on stress wave transmission and reflection 被引量:5
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作者 Xin Chen Mei-feng Cai +1 位作者 Jian-chuan Li Wen-hui Tan 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第11期1237-1245,共9页
Taking the joint matching coefficient(JMC) which represents the contact area ratio of the joint in rock masses as the key parameter, a one-dimensional contacted interface model(CIM-JMC) was established in this study t... Taking the joint matching coefficient(JMC) which represents the contact area ratio of the joint in rock masses as the key parameter, a one-dimensional contacted interface model(CIM-JMC) was established in this study to describe the wave propagation across a single joint. According to this model, the reflected and transmitted waves at the joint were obtained, and the energy coefficients of reflection and transmission were calculated. Compared with the modified Split Hopkinson pressure bar(SHPB) experiment, it was validated by taking the incident wave of the SHPB test as the input condition in the CIM-JMC, and the reflected and transmitted waves across the joint were calculated by the model. The effects of four sets of JMCs(0.81, 0.64, 0.49, and 0.36) on the transmission and reflection of the stress wave propagation across the joint were analyzed and compared with the experimental results. It demonstrated that the values of CIM-JMC could represent both the transmission and reflection of the stress wave accurately when JMC > 0.5, but could relatively accurately represent the reflection rather than the transmission when JMC < 0.5. By contrasting energy coefficients of joints with different JMCs, it was revealed that energy dissipated sharply along the decrease of JMC when JMC > 0.5. 展开更多
关键词 joint MATCHING COEFFICIENT stress wave TRANSMISSION REFLECTION energy COEFFICIENT ROCK dynamics
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Effects of imperfect experimental conditions on stress waves in SHPB experiments 被引量:5
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作者 Xianqian Wu Qiuyun Yin +1 位作者 Yanpeng Wei Chenguang Huang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第6期827-836,共10页
Experimental and numerical simulations were undertaken to estimate the effects of imperfect conditions on stress waves in split Hopkinson pressure bar (SHPB) experiments. The photonic Doppler velocimetry (PDV) mea... Experimental and numerical simulations were undertaken to estimate the effects of imperfect conditions on stress waves in split Hopkinson pressure bar (SHPB) experiments. The photonic Doppler velocimetry (PDV) measurement results show that the rise and fall times of an incident wave increases with an increasing inclination angle; also, the fluctuations of the incident wave disappear gradually with the increase of inclination angle. The following characteristics for various defects in the SHPB were obtained by numerical simulation: (1) the influence of a curved bar was negligible; (2) misalignment modestly affects the fluctuation characteristics, and bending waves were generated at this condition; (3) inclination and indentation of the impact end- surface had a great impact on the incident waves, and both of them increase the rise time of the incident wave by increasing the degree of defects. In view of the results, misalignment, inclination, and indentation in SHPB experiments should be minimized. 展开更多
关键词 Imperfect experimental conditions SHPBexperiments stress waves PDV measurement. Numericalsimulation
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Dynamic response and failure of rock in initial gradientstress field under stress wave loading 被引量:10
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作者 WENG Lei WU Qiu-hong +1 位作者 ZHAO Yan-lin WANG Shi-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第3期963-972,共10页
Once an opening is created in deep underground,the stresses surrounding the opening will be redistributed,inducing a gradient stress field.To understand how the ground rock in such a gradient stress field responses to... Once an opening is created in deep underground,the stresses surrounding the opening will be redistributed,inducing a gradient stress field.To understand how the ground rock in such a gradient stress field responses to dynamic stress loading,the gradient stress distribution at a circular opening was first analyzed and the propagation of 1D stress wave in rock mass under gradient stress field was theoretically derived.By using an implicit to explicit solution method in LS-DYNA code,the dynamic mechanical behaviors of rock in gradient stress field were numerically investigated.The results indicate that the damage is mainly produced at or near the free face,partly due to the straight action of compressive stress wave and the tensile stress wave generated at the free face.The range of the induced damage zone is narrowed under the conditions of higher gradient stress rate and lower dynamic stress amplitude.However,under lower gradient stress field and higher dynamic stress,the damage becomes severer and wider with discontinuous failure regions. 展开更多
关键词 deep opening gradient stress rate(GSR) stress wave damage zone LS-DYNA
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