http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Xibing Li (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
The influence of initial stress on wave propagation and dynamic elastic coefficients
Li, Xibing,Tao, Ming Techno-Press 2015 Geomechanics & engineering Vol.8 No.3
The governing equations of wave propagation in one dimension of elastic continuum materials are investigated by taking the influence of the initial stress into account. After a short review of the theory of elastic wave propagation in a rock mass with an initial stress, results indicate that the initial stress differentially influences P-wave and S-wave propagation. For example, when the initial stress is homogeneous, for the P-wave, the initial stress only affects the magnitude of the elastic coefficients, but for the S-wave, the initial stress not only influences the elastic coefficients but also changes the governing equation of wave propagation. In addition, the P-wave and S-wave velocities were measured for granite samples at a low initial stress state; the results indicate that the seismic velocities increase with the initial stress. The analysis of the previous data of seismic velocities and elastic coefficients in rocks under ultra-high hydrostatic initial stress are also investigated.
-
Enhanced plasticity of twin-roll cast ZK60 magnesium alloy through differential speed rolling
Gong, Xibing,Kang, Suk Bong,Li, Saiyi,Cho, Jae Hyung Elsevier 2009 MATERIALS AND DESIGN Vol.30 No.9
<P><B>Abstract</B></P><P>ZK60 magnesium alloy strips were produced by twin-roll cast (TRC) and then subjected to differential speed rolling (DSR) with a velocity ratio of 1:1.2 and 1:1.5. Microstructures, textures and mechanical properties of the DSR-processed sheets were compared with those of equal speed rolling (ESR) to examine the effects of velocity ratio. The sheets processed by DSR showed significantly higher elongation and slightly lower tensile strength than those of the ESR-processed sheet, which can be attributed to the inclination and weakening of the basal fiber texture. Combining the DSR and TRC techniques is suggested to be an effective way of plasticity enhancement of the magnesium alloys, in additional to apparent advantages in energy saving.</P>
-
A numerical study on the damage of projectile impact on concrete targets
Gang Lu,Xibing Li,Kejin Wang 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.9 No.1
This paper presents the numerical simulation of the rigid 12.6 mm diameter kinetic energy ogive-nosed projectile impact on plain and fiber reinforced concrete (FRC) targets with compressive strengths from 45 to 235 MPa, using a three-dimensional finite element code LS-DYNA. A combined dynamic constitutive model, describing the compressive and tensile damage of concrete, is implemented. A modified Johnson_Holmquist_Cook (MJHC) constitutive relationship and damage model are incorporated to simulate the concrete behavior under compression. A tensile damage model is added to the MJHC model to analyze the dynamic fracture behavior of concrete in tension, due to blast loading. As a consequence, the impact damage in targets made of plain and fiber reinforced concrete with same matrix material under same impact velocities (650 m/s) are obtained. Moreover, the damage distribution of concrete after penetration is procured to compare with the experimental results. Numerical simulations provide a reasonable prediction on concrete damage in both compression and tension.
-
Determination of spalling strength of rock by incident waveform
Tao, Ming,Zhao, Huatao,Li, Xibing,Ma, Jialu,Du, Kun,Xie, Xiaofeng Techno-Press 2017 Geomechanics & engineering Vol.12 No.1
An experimental technique for determining the spalling strength of rock-like materials under a high strain rate is developed. It is observed that the spalling strength of a specimen can be determined by only knowing the wavelength, loading peak value and length of the first spallation of an incident wave under a specific loading waveform. Using this method in combination with a split-Hopkinson pressure bar (SHPB) and other experimental devices, the spalling strength of granite specimens under a high strain rate is tested. Comparisons with other experimental results show that the new measuring method can accurately calculate the dynamic tensile strength of rock materials under a high strain rate.
-
Theoretical and numerical analysis of the influence of initial stress gradient on wave propagations
Tao, Ming,Chen, Zhenghong,Li, Xibing,Zhao, Huatao,Yin, TuBing Techno-Press 2016 Geomechanics & engineering Vol.10 No.3
The investigation of stress wave propagation in a medium with initial stress has very important application in the field of engineering. However, the previous research less consider the influence of initial stress gradient on wave propagation. In the present paper, the governing equation of wave propagation in elastic continuum material with inhomogeneous initial stress is derived, which indicated that the inhomogeneous initial stress changed the governing equation of wave propagation. Additionally, the definite problem of wave propagation in material with initial stress gradient is verified by using mathematical physics method. Based on the definite problem, the elastic displacement-time relationship of wave propagation is explored, which indicated that the inhomogeneous initial stress changed waveform and relationship of displacement-time histories. Furthermore, the spall process of blasting wave propagation from underground to earth surface is simulated by using LS-DYNA.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
