Laboratory Testing to Research the Micro-Structure and Dynamic Characteristics of Frozen–Thawed Marine Soft Soil

Ding

et al. 2020

JMSE

Self Cite

Coral sand is an important filler resource that can solve the shortage of terrestrial fillers in coastal areas. Recently, the foundations of many infrastructures in the South China Sea have been built with coral sand as fillers, which have been subjected to wave and traffic cyclic loads. Resilient modulus (Mr) is an important design parameter in marine engineering, but there are few studies on the resilient modulus response of coral sand under cyclic loading. A series of drained cyclic triaxial tests were carried out to investigate the effects of the initial mean effective stress (p0) and cyclic stress ratio (ζ) on the resilient modulus response of the coral sand from the South China Sea. The change of fractal dimension (αc) can reflect the rule of particle breakage evolution. The αc of coral sand shows a tendency of almost maintaining stable and then increasing rapidly with the increase of mean effective stress p0 under each cyclic stress ratio ζ. There is a threshold of p0, when the p0 exceeds this threshold, αc will increase significantly with the increase of p0. The increase of p0 has a beneficial effect on the improvement of the Mr, while the increase of ζ has both beneficial and detrimental effects on the improvement of the Mr. A new prediction model of the Mr considering particle breakage was established, which can better predict the Mr of coral sand in the whole stress interval. The research results can provide guidance for the design of marine transportation infrastructures, which can promote the development of marine transportation industry and energy utilization.

Section: Test Methodsmentioning

confidence: 99%

Experimental and Estimation Studies of Resilient Modulus of Marine Coral Sand under Cyclic Loading

Ding

et al. 2020

JMSE

Self Cite

“…With the continuous development of the social economy, the positioning control of the tandem robot arm is based on the inverse kinematics model; that is, for a given robot end effector's spatial pose, the motors of each joint are driven to run at the angle of rotation calculated by the inverse kinematics solution to reach the specified position [1][2][3]. However, in the actual work, due to many factors such as machining, working environment, and so on, the robot kinematics model has errors, which lead to the inaccuracy of the actual position and pose, thus affecting the absolute positioning accuracy of the robot [4].…”

Section: Introductionmentioning

confidence: 99%

Robust Optimization of Dynamic Characteristics of Mechanical Structure Combined with Multivariable Predictive Compensation

Mobile Information Systems

2022

Due to the influence of many factors such as machining and working environment, the robot kinematics model has errors, which leads to the inaccuracy of the actual position and pose. Therefore, in order to solve this problem, this paper proposes a method based on the genetic algorithm to directly modify the rotation variables of the manipulator joint to improve the positioning accuracy of the manipulator. Through the establishment of the mechanical kinematics model and the error model, the solution formula of joint correction is obtained. The actual pose of the end effector of the manipulator is detected by the NDI three-dimensional dynamic displacement measurement system, and the correction value is applied to the control of the designed 6-DOF series manipulator.

“…Jiang et al [16] studied the distribution characteristics and change principles of pores under traffic load. Ding et al [17] researched the microscopic characteristics of frozen-thawed soft marine soil under cyclic loading using a scanning electron microscope and explained the potential reasons for the change in the macroscopic dynamic characteristics from the microscopic point of view. Zhou et al [18] introduced a directional probability entropy approach to analyze the micro parameters of SEM and proposed a macro and micro coupling creep model of soft marine soil.…”

Section: Introductionmentioning

confidence: 99%

Variation in Micro-Pores during Dynamic Consolidation and Compression of Soft Marine Soil

Dai

et al. 2021

JMSE

In this study, to explore the microstructure deformation mechanism of marine soft marine soil under cyclic loading, we analyzed the dynamic properties of soft marine soil under cyclic loading via dynamic consolidation compression testing. Then, using Image-Pro Plus (IPP) 6.0 image analysis software, and according to the dynamic consolidation compression test results and the images from a scanning electron microscope (SEM), we determined the weakening effect of soft soils under different consolidation confining pressures, different cyclic stress ratios, and different over-consolidation ratios. After dynamic consolidation and compression, the pore structure of undisturbed soft marine soil tends to compact, the degree of soil particle fragmentation intensifies, small pores increase, large pores decrease, the pores become more regular, and the distribution of pores is directional. Subsequently, for undisturbed soft marine soil, the higher the consolidated confining pressure, cyclic dynamic stress ratio, and over-consolidation ratio, the greater the damage to the pore structure, and the more obvious the structural weakening effect exhibited under cyclic loading.