scholarly journals Calculation of the Influence Zone for Planetary Sampling Based on DEM Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qian Li ◽  
Junping Li ◽  
Lanlan Xie
Keyword(s):  
Soil Mechanics ◽  
Reaction Force ◽  
Lunar Soil ◽  
Sampling Device ◽  
Influence Zone ◽  
Dem Simulation ◽  
Related Research ◽  
Physical Experiments ◽  
Device Structures ◽  
Force Calculation

In the design of planetary sampling devices, calculating the reaction force acting on the sampling devices is crucial. According to related research, the influence zone caused by sampling plays an important role in calculating the reaction force. A new method for estimating the range of the influence zone based on 3D DEM simulation is discussed in this paper. Taking lunar soil as an example, first, via validation of physical experiments, the DEM lunar soil simulant was proven to have mechanical properties similar to those of real lunar soil. Second, stress was selected as an indicator to identify the influence zone by computing the match percentage via a comparison between classical soil mechanics and DEM simulation. Using the proposed calculation method, it can be observed that the trend of change of influence zone at different sampling moments showed similar to the change of reaction force. Calculation of the influence zone can be used to analyze the reaction force of different gravity environments, sampling device structures, and motions.

scholarly journals Infinite Element Static-Dynamic Unified Artificial Boundary

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhiqiang Song ◽  
Fei Wang ◽  
Yujie Liu ◽  
Chenhui Su
Keyword(s):  
Reaction Force ◽  
Tangential Direction ◽  
Dynamic Effects ◽  
Artificial Boundary ◽  
Infinite Element ◽  
Dynamic Synthesis ◽  
Dynamic Boundary ◽  
Static Calculation ◽  
Force Calculation ◽  
External Wave

The method, which obtains a static-dynamic comprehensive effect from superposing static and dynamic effects, is inapplicable to large deformation and nonlinear elastic problems under strong earthquake action. The static and dynamic effects must be analyzed in a unified way. These effects involve a static-dynamic boundary transformation problem or a static-dynamic boundary unified problem. The static-dynamic boundary conversion method is tedious. If the node restraint reaction force caused by a static boundary condition is not applied, then the model is not balanced at zero moment, and the calculation result is distorted. The static numerical solution error is large when the structure possesses tangential static force in a viscoelastic static-dynamic unified boundary. This paper proposed a new static-dynamic unified artificial boundary based on an infinite element in ABAQUS to solve static-dynamic synthesis effects conveniently and accurately. The static and dynamic mapping theories of infinite elements were introduced. The characteristic of the infinite element, which has zero displacement at faraway infinity, was discussed in theory. The equivalent nodal force calculation formula of infinite element unified boundary was deduced from an external wave input. A calculation and application program of equivalent nodal forces was developed using the Python language to complete external wave inputting. This new method does not require a static and dynamic boundary transformation and import of stress field and constraint counterforce of boundary nodes. The static calculation precision of the infinite element unified boundary is more improved than the viscoelastic static-dynamic unified boundary, especially when the static load is in the tangential direction. In addition, the foundation simulation range of finite field can be significantly reduced given the utilization of the infinite element static dynamic unified boundary. The preciseness of static calculation and dynamic calculation and static-dynamic comprehensive analysis are unaffected.

scholarly journals Dynamic analysis of a ten-link tooth-lever differential transmission

2021 ◽  
Vol 939 (1) ◽  
pp. 012024
Author(s):  
A Abdukarimov ◽  
I Saidakulov
Keyword(s):  
High Speed ◽  
Reaction Force ◽  
Transmission Mechanism ◽  
Force Analysis ◽  
Axis Of Rotation ◽  
Processed Material ◽  
Differential Transmission ◽  
External Forces ◽  
Force Calculation ◽  
Force Characteristics

Abstract This article discusses the dynamics of a ten-link tooth-lever differential transmission mechanism. The force analysis of the transmission mechanism is given in order to find the dependence for determining the reaction in kinematic pairs and the balancing moment of the pair of forces and to show some features of the tooth-lever transmission mechanism. The force calculation was carried out taking into account the accelerated movement of links since their acceleration in modern high-speed machines is very significant. To obtain a more accurate concept of the external forces and moments loading the transmission mechanism in the accelerated movement of the links, the dynamics of the transient process of roller technological machines was considered. Cases of feeding the processed material were considered both from the side of the intermediate gears and from the side opposite to the parasitic gears. Dependencies were obtained to determine the force characteristics of this mechanism. Cases of pressure unloading and overloading on the processed material from the side of the free shaft, depending on the location of the transmission mechanism are shown. The dependence of the reaction force of intermediate gears on their own axes of rotation on the angle between the levers is shown. With an increase in the angle between the levers, the reaction of the intermediate gears on the axis of rotation increases.

Analysis of Buffering Properties of Honeycomb Material

2012 ◽  
Vol 482-484 ◽  
pp. 1146-1149
Author(s):  
Ming Bo Yang ◽  
Jin Bao Chen ◽  
Fei Deng ◽  
Meng Chen
Keyword(s):  
Theoretical Analysis ◽  
Material Properties ◽  
Orthotropic Material ◽  
Soil Mechanics ◽  
Material Model ◽  
Lunar Soil ◽  
Equivalent Material ◽  
User Material Model ◽  
Honeycomb Material ◽  
Equivalent Material Properties

The buffering properties of honeycomb material are analyzed in the presented work. Theoretical analysis based on energy method is first presented, the buffering process of honeycomb material can be divided into three phases, honeycomb material can be equivalent to orthotropic material and the equivalent material properties are given. Being good at soil mechanics, Abaqus can simulate lunar soil very well. Using a constitutive model for honeycomb material, which is a built-in user material model, the presented work developed a honeycomb material simulation model and verified with a practical example. Now we can analysis the entire landing buffer process in Abaqus, which is a complement to existing analysis processes.

Development a Device for Measuring Soil Mechanical Properties

2011 ◽  
Vol 110-116 ◽  
pp. 4445-4450
Author(s):  
Gholamhosein Shahgoli ◽  
J. Nasrollahi Azar ◽  
Yousef Abbaspour-Gilandeh
Keyword(s):  
Soil Mechanics ◽  
Reaction Force ◽  
Soil Reaction ◽  
Cone Penetrometer ◽  
Mechanical Parameters ◽  
Data Logger ◽  
Shear Plate ◽  
The University ◽  
Penetration Tests

In tillage operations to know soil reaction force on the tools working inside soil and under agricultural vehicle tires, soil mechanical parameters should be determined. Measurement and determination of soil mechanical parameters will be helpful for optimum designing of tillage tools to decrease required energy. An experimental device was developed at the University of Mohaghegh Ardabil which is able to conduct three soil mechanics tests of sinkage, penetration and shear, by which soil cohesion, internal friction, stiffness, soil constant and strength were determined. For sinkage and penetration tests an electromotor power was translated to a rectangle plate via a translating system such that moves plate or cone penetrometer vertically and forces it in soil. While fore shear test it moves shear plate horizontally as plate shears the soil. Required forces for sinkage, penetration and shearing were measured by loadcell and vertical and horizontal displacements were measure using linear potentiometer (LVDT). All data logged to a loptop via a data logger. All mentioned parameters for a type of soil were computed desirably related tests.

scholarly journals Development of a Knee Joint CT-FEM Model in Load Response of the Stance Phase During Walking Using Muscle Exertion, Motion Analysis, and Ground Reaction Force Data

Medicina ◽  
2020 ◽  
Vol 56 (2) ◽  
pp. 56
Author(s):  
Kunihiro Watanabe ◽  
Hirotaka Mutsuzaki ◽  
Takashi Fukaya ◽  
Toshiyuki Aoyama ◽  
Syuichi Nakajima ◽  
...  
Keyword(s):  
Finite Element ◽  
Knee Joint ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
Equivalent Stress ◽  
Element Model ◽  
Calculation Model ◽  
Quantitative Ct ◽  
Load Response ◽  
Force Calculation

Background and objectives: There are no reports on articular stress distribution during walking based on any computed tomography (CT)-finite element model (CT-FEM). This study aimed to develop a calculation model of the load response (LR) phase, the most burdensome phase on the knee, during walking using the finite element method of quantitative CT images. Materials and Methods: The right knee of a 43-year-old man who had no history of osteoarthritis or surgeries of the knee was examined. An image of the knee was obtained using CT and the extension position image was converted to the flexion angle image in the LR phase. The bone was composed of heterogeneous materials. The ligaments were made of truss elements; therefore, they do not generate strain during expansion or contraction and do not affect the reaction force or pressure. The construction of the knee joint included material properties of the ligament, cartilage, and meniscus. The extensor and flexor muscles were calculated and set as the muscle exercise tension around the knee joint. Ground reaction force was vertically applied to suppress the rotation of the knee, and the thigh was restrained. Results: An FEM was constructed using a motion analyzer, floor reaction force meter, and muscle tractive force calculation. In a normal knee, the equivalent stress and joint contact reaction force in the LR phase were distributed over a wide area on the inner upper surface of the femur and tibia. Conclusions: We developed a calculation model in the LR phase of the knee joint during walking using a CT-FEM. Methods to evaluate the heteromorphic risk, mechanisms of transformation, prevention of knee osteoarthritis, and treatment may be developed using this model.

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