Creep Behavior of Unsaturated Reticulate Red Clay Under Matric Suction

Jianzhong Li,Yuanli Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

In order to study unsaturated creep behaviors of reticulate red clay under matric suction, a series of isotropic creep tests with different matric suction level were carried out by using Geotechnical Digital Systems (GDS) unsaturated apparatus. Results indicate that creep strain caused by matric suction increases with the increasing of matric suction level and tends to certain stability over time. Based on the analyses of test results, a creep model for the unsaturated reticulate red clay under matric suction was established to predict the creep strain caused by matric suction. In the model, a new parameter M (matric suction level) was defined as a ratio of the matric suction to the net confining pressure, a hyperbolic function was adopted for the description of the strain-time relationship and an exponential function was employed for the strain-M relationship. Predicted results are in good agreement with the test results shows that the model can reasonably simulate the effects of matric suction on creep properties of unsaturated reticulate red clay.

Matric Suction Creep Characteristics of Reticulated Red Clay

Jianzhong Li,Yuanli Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Matric suction creep is the creep of unsaturated soil caused by loading constant matric suction. Matric suction creep characteristics of reticulated red clay with constant net confing pressure and step-loading matric suction was studied using stress-controlling unsaturated triaxial test apparatus. Test and analysis results show that: (1) with constant net confining pressure, axial and radial strain of the clay caused by creep due to matric suction increases obviously; (2) the increments of axial strain of the clay, caused by creep due to matric suction under constant net confining pressure, is not the same as that of radial strain, and the absolute value of radial strain is bigger than that of axial strain; (3) creep strain produced by the same amount of matric suction decreases as the increasing of the matric suction during step loading creep, which means that matric suction makes the clay hard; and (4) the creep strain-time curves of both axial and radial creep can be simulated very well by exponential decay function, and the parameters of the function are matric suction depend obviously.

Research on Suction Equilibrium Time of Unsaturated Reticulate Red Clay

Jianzhong Li,Hao Kangning,Peng Feng 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

Filter paper technique, humidity control technique and axis translation technique were used to study suction equilibrium time of unsaturated reticulate red clay. Test results show that: (a) suction equilibrium exists in both suction measurement or suction control using any technique in the tests; (b) suction equilibrium time of unsaturated reticulate red clay can be as short as several tens hour or several days for different suction measuring techniques, or long as several days or several tens day for different suction controlling techniques; (c) suction equilibrium time consumed in process of suction measurement is shorter than that of suction control using the same technique; (d) suction equilibrium time in measuring matric suction of unsaturated reticulate red clay using axis translation technique is shorter than that using filter paper technique; and (e) suction equilibrium time of drying process is much longer than that of wetting process, when suction is controlled using humidity control technique.

Dumb-bell Shaped Magnetostrictive/Piezoelectric Transducer

Jianzhong Li,Yumei Wen,Ping Li 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Application of computer algorithms for modelling and numerical solution of dynamic bending

Jianzhong Qiu,Naichang Dai,Akbar Shafiei Alavijeh 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.1

In this paper, static and dynamic bending of nanocomposite micro beam armed with CNTs considering agglomeration effect is studied. The structural damping is considered by Kelvin-Voigt model. The agglomeration effects are assumed using Mori-Tanaka model. The micro beam is modeled by third order shear deformation theory (TSDT). The motion equations are derived by principle of Hamilton’s and energy method assuming size effects on the basis of Eringen theory. Using differential quadrature method (DQM) and Newmark method, the static and dynamic deflections of the structure are obtained. The effects of agglomeration and CNTs volume percent, damping of structure, nonlocal parameter, length and thickness of micro-beam are presented on the static and dynamic deflections of the nanocomposite structure. Results show that with increasing CNTs volume percent, the static and dynamic deflections are decreased. In addition, enhancing the nonlocal parameter yields to higher static and dynamic deflections.

Dynamic tensile behaviour of reactive powder concrete by Hopkinson bar experiments and numerical simulation

Jianzhong Lai,Wei Sun 사단법인 한국계산역학회 2010 Computers and Concrete, An International Journal Vol.7 No.1

Accuracy analysis and error compensation for Tricept machine tool under load

Jianzhong Ding,Chunjie Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

This paper provides an efficient way to estimate the accuracy performance of the Tricept machine tool under load. Both joint clearances and link flexibility are considered. Clearances of the spherical joints and universal joint are considered, and the small change in link length arisen from clearances and deformation is modeled with the hyperbolic function. The kinetostatic model for accuracy analysis is obtained by balancing the employed load and the elastic forces provided by limbs. Moreover, an error compensation method for the Tricept machine tool under load is presented. The proposed methods are further illustrated and validated using a study case, and the feasibility of the error compensation method is discussed. This paper gives a deep insight into the effects of clearances, flexibility and loads on the accuracy performance of the Tricept-like mechanisms and instructive conclusions are drawn for accuracy improvement.

Accuracy analysis of a parallel positioning mechanism with actuation redundancy

Jianzhong Ding,Chunjie Wang,Hongyu Wu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

A forward accuracy analysis method based on Lie-group theory and screw theory is proposed to analyze the pose error of parallel mechanisms with actuation redundancy. Both the input uncertainty and components stiffness were considered. The method was applied to study the accuracy performance of a positioning mechanism, which has the potential to be used for the positioning of satellite antenna, camera, astronomical telescope and so on. The advancement of the method is that it models the elastic deformation and passive joint motions together by motion vector and limb stiffness matrix, which greatly simplifies the constraints modeling process. Mean value and standard deviation of the pose errors under different working conditions were obtained by optimal Latin hypercube sampling method, which reduces the sampling size on the premise of ensuring the precision. Finally, the robust optimization was employed to give further insight into the effects of redundant limb and mechanism structure on the accuracy performance of the actuation-redundant mechanism.

Rational analysis model and seismic behaviour of tall bridge piers

Jianzhong Li,Zhongguo Guan,Zhiyao Liang 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.1

This study focuses on seismic behaviour of tall piers characterized by high slender ratio. Two analysis models were developed based on elastic-plastic hinged beam element and elastic-plastic fiber beam element, respectively. The effect of the division density of elastic-plastic hinged beam element on seismicdemand was discussed firstly to seek a rational analysis model for tall piers. Then structural seismicbehaviour such as the formation of plastic hinges, the development of plastic zone, and the displacement at the top of the tall piers were investigated through incremental dynamic analysis. It showed that the seismic behaviour of a tall pier was quite different from that of a lower pier due to higher modes contributions. In a tall pier, an additional plastic zone may occur at the middle height of the pier with the increase of seismicexcitation. Moreover, the maximum curvature reaction at the bottom section and maximum lateral displacement at the top turned out to be seriously out of phase for a tall pier due to the higher modes effect, and thus pushover analysis can not appropriately predict the local displacement capacity.

Asymmetric Multiple-Image Encryption Based on Octonion Fresnel Transform and Sine Logistic Modulation Map

Jianzhong Li 한국광학회 2016 Current Optics and Photonics Vol.20 No.3

A novel asymmetric multiple-image encryption method using an octonion Fresnel transform (OFST) anda two-dimensional Sine Logistic modulation map (2D-SLMM) is presented. First, a new multiple-imageinformation processing tool termed the octonion Fresneltransform is proposed, and then an efficient methodto calculate the OFST of an octonion matrix is developed. Subsequently this tool is applied to processmultiple plaintext images, which are represented by octonion algebra, holistically in a vector manner. Thecomplex amplitude, formed from the components of the OFST-transformed original images and modulatedby a random phase mask (RPM), is used to derive the ciphertext image by employing an amplitude- andphase-truncation approach in the Fresnel domain. To avoid sending whole RPMs to the receiver side fordecryption, a random phase mask generation method based on SLMM, in which only the initial parametersof the chaotic function are needed to generate the RPMs, is designed. To enhance security, the ciphertextand two decryption keys produced in the encryption procedure are permuted by the proposed SLMM-basedscrambling method. Numerical simulations have been carried out to demonstrate the proposed scheme'svalidity, high security, and high resistance to various attacks.