scholarly journals Dynamic Response of the Skull with Sinuses under Blunt Frontal Impact: A Three-Dimensional Computational Study

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xuewei Song ◽  
Botao Zhao ◽  
Cong Wang ◽  
Nan Wang
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Local Area ◽  
Local Effect ◽  
Impact Response ◽  
Stress And Strain ◽  
Frontal Impact ◽  
Facial Bones ◽  
Distribution Of Stress

The objective of this study is to analyze the biomechanical effects of sinuses in the skull on the facial impact response. Two models were built, where one had sinuses and the other had none. The models were verified using cadaver test data, including impacts to frontal bone, zygomatic bone, and maxillae. In the maxilla and zygoma impact, sinuses were found to have no significant effect on the global distribution of stress or stiffness of facial bones, and the influence was limited in local area. In forehead impact, the sinuses significantly affected the distribution of stress and strain in the skull due to its location in facial bones. The result shows that if the sinus is far away from the location of impact, its effect on the overall response of skull could be ignored. In addition, the distance between the region of interest and sinuses is another important parameter when studying the local effect of sinuses.

The Non-Newtonian Fluid in the Collision

2014 ◽  
Vol 538 ◽  
pp. 72-75
Author(s):  
Lei Hou ◽  
Jun Jie Zhao ◽  
Lin Qiu
Keyword(s):  
High Performance ◽  
Plastic Material ◽  
Three Dimensional ◽  
Strain Curve ◽  
Step Length ◽  
Stress And Strain ◽  
Equation Analysis ◽  
Elastic Plastic Material ◽  
Discrete Finite Element ◽  
Distribution Of Stress

This paper studies elastic-plastic material deformation in terms of Cauchy and PTT. It gives certain convergence to the equation analysis in the discrete finite element method; it reaches o (h2+Δt) under the certain step length. Then we carry on Three-dimensional numerical simulation by the high performance software LS-DYNA and the distribution of stress and strain curve is observed.

scholarly journals Analysis of the dependence of stresses and deformations on the surfaces of shoe soles of different thicknesses and materials

2021 ◽  
Vol 273 ◽  
pp. 05001
Author(s):  
Olesya Golubeva ◽  
Alina Pogorelova
Keyword(s):  
Three Dimensional ◽  
Stress And Strain ◽  
Medium Density ◽  
Suitable Material ◽  
Two Component ◽  
Shoe Soles ◽  
Three Dimensional Models ◽  
Materials Used ◽  
Distribution Of Stress ◽  
Shape And Size

For this study, three-dimensional models of the soles of work shoes of different thicknesses and consisting of different materials were created. These models were analyzed to obtain the distribution of stress and strain on their surfaces. To build the model, we used experimental data on the shape and size of the sole, as well as the properties of specific materials used in the manufacture of soles for work shoes used in agriculture. The goal was to determine the most suitable material, that is, which of the materials has the most suitable characteristics for the sole, has the best wear resistance when used in agriculture. We noticed a significant reduction in deformations on the surface of the sole with an increase in the thickness of the sole, as well as when using two-component casting of the sole from a combination of materials: low-density EVA and flexible PU, medium-density EVA and soft PVC. This indicates their advantages and maximum suitability.

Influence of Extrusion Ratio on Forming of Thick-Walled Tube

2011 ◽  
Vol 217-218 ◽  
pp. 952-957
Author(s):  
Jian Zhang ◽  
Jian Hua Song ◽  
Xiao Lan Wang ◽  
Xue Qin Jin ◽  
Zhi Hua Wang
Keyword(s):  
Large Diameter ◽  
Three Dimensional ◽  
Extrusion Process ◽  
Extrusion Ratio ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Modeling Software ◽  
Distribution Of Stress

Employed DEFORM software to simulate vertical extrusion of large diameter thick-walled pipe, by using the Finite Element Method in the three-dimensional modeling software Pro/E of the CAD platform. Analyze the law of blank flow in extrusion process, distribution of stress and strain, and the influence of different extrusion ratio on deformation of thick-walled tube comparatively.

Three-Dimensional Computational Study of Natural Convection in a Non-Uniformly Heated Vertical Open-Ended Channel

2014 ◽  
Author(s):  
Oxana A. Tkachenko ◽  
Svetlana A. Tkachenko ◽  
Victoria Timchenko ◽  
John A. Reizes ◽  
Guan Heng Yeoh ◽  
...  
Keyword(s):  
Natural Convection ◽  
Computational Study ◽  
Three Dimensional

Wake Flow of Single and Multiple Yawed Cylinders

2004 ◽  
Vol 126 (5) ◽  
pp. 861-870 ◽  
Author(s):  
A. Thakur ◽  
X. Liu ◽  
J. S. Marshall
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Side Wall ◽  
Wake Flow ◽  
Upstream Region ◽  
Two Dimensional ◽  
Cylinder Wake ◽  
Dimensional Approximation ◽  
The Face ◽  
Drag And Lift

An experimental and computational study is performed of the wake flow behind a single yawed cylinder and a pair of parallel yawed cylinders placed in tandem. The experiments are performed for a yawed cylinder and a pair of yawed cylinders towed in a tank. Laser-induced fluorescence is used for flow visualization and particle-image velocimetry is used for quantitative velocity and vorticity measurement. Computations are performed using a second-order accurate block-structured finite-volume method with periodic boundary conditions along the cylinder axis. Results are applied to assess the applicability of a quasi-two-dimensional approximation, which assumes that the flow field is the same for any slice of the flow over the cylinder cross section. For a single cylinder, it is found that the cylinder wake vortices approach a quasi-two-dimensional state away from the cylinder upstream end for all cases examined (in which the cylinder yaw angle covers the range 0⩽ϕ⩽60°). Within the upstream region, the vortex orientation is found to be influenced by the tank side-wall boundary condition relative to the cylinder. For the case of two parallel yawed cylinders, vortices shed from the upstream cylinder are found to remain nearly quasi-two-dimensional as they are advected back and reach within about a cylinder diameter from the face of the downstream cylinder. As the vortices advect closer to the cylinder, the vortex cores become highly deformed and wrap around the downstream cylinder face. Three-dimensional perturbations of the upstream vortices are amplified as the vortices impact upon the downstream cylinder, such that during the final stages of vortex impact the quasi-two-dimensional nature of the flow breaks down and the vorticity field for the impacting vortices acquire significant three-dimensional perturbations. Quasi-two-dimensional and fully three-dimensional computational results are compared to assess the accuracy of the quasi-two-dimensional approximation in prediction of drag and lift coefficients of the cylinders.

scholarly journals Data-Informed Decomposition for Localized Uncertainty Quantification of Dynamical Systems

Vibration ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 49-63
Author(s):  
Waad Subber ◽  
Sayan Ghosh ◽  
Piyush Pandita ◽  
Yiming Zhang ◽  
Liping Wang
Keyword(s):  
Dynamical Systems ◽  
Computational Cost ◽  
Three Dimensional ◽  
Region Of Interest ◽  
System Response ◽  
Computational Domain ◽  
User Interest ◽  
Numerical Resolution ◽  
Multi Scale ◽  
Operation Conditions

Industrial dynamical systems often exhibit multi-scale responses due to material heterogeneity and complex operation conditions. The smallest length-scale of the systems dynamics controls the numerical resolution required to resolve the embedded physics. In practice however, high numerical resolution is only required in a confined region of the domain where fast dynamics or localized material variability is exhibited, whereas a coarser discretization can be sufficient in the rest majority of the domain. Partitioning the complex dynamical system into smaller easier-to-solve problems based on the localized dynamics and material variability can reduce the overall computational cost. The region of interest can be specified based on the localized features of the solution, user interest, and correlation length of the material properties. For problems where a region of interest is not evident, Bayesian inference can provide a feasible solution. In this work, we employ a Bayesian framework to update the prior knowledge of the localized region of interest using measurements of the system response. Once, the region of interest is identified, the localized uncertainty is propagate forward through the computational domain. We demonstrate our framework using numerical experiments on a three-dimensional elastodynamic problem.

scholarly journals How Effective Is the Green Development Policy of China’s Yangtze River Economic Belt? A Quantitative Evaluation Based on the PMC-Index Model

2021 ◽  
Vol 18 (14) ◽  
pp. 7676
Author(s):  
Shengli Dai ◽  
Weimin Zhang ◽  
Jiamin Zong ◽  
Yingying Wang ◽  
Ge Wang
Keyword(s):  
Yangtze River ◽  
Three Dimensional ◽  
Local Area ◽  
Surface Model ◽  
Policy Effectiveness ◽  
Index Model ◽  
Advantages And Disadvantages ◽  
Green Development ◽  
Development Policies ◽  
Policy Texts

Although many countries around the world, especially China, highlight the strategy of green development, there has been little research evaluating the effectiveness of green development policies in local area. This study explores 16 policy texts with the theme of green development in the Yangtze River Economic Belt in China. Using the Policy Modeling Consistency Index (PMC-Index) model, the paper establishes a multi-input–output policy table and scientifically and systematically evaluates these policies. The results show that the average PMC index of the 16 policy texts is 6.83, indicating a high overall quality of policy texts. The index identifies two states of policy effectiveness as being good and excellent; 50% of the total texts fall into these categories and do not fall into the category of having a low level of policy effectiveness. Five indicators, including policy timeliness, social benefits, policy audience scope, and incentives and constraints, significantly impact the PMC-Index of the policy. Six representative policy samples were selected and analyzed. The advantages and disadvantages of the policy can be more fully understood by the degree of depression of the PMC’s three-dimensional curved surface (PMC-Surface) model. Finally, the paper provides theoretical recommendations for the optimization of the green development policies.

scholarly journals Crystal Structure and Computational Study on Methyl-3-Aminothiophene-2-Carboxylate

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Yaping Tao ◽  
Ligang Han ◽  
Andong Sun ◽  
Kexi Sun ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Crystal Packing ◽  
Computational Study ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Dispersion Energy ◽  
Monoclinic Crystal ◽  
Hydrogen Bond Interactions ◽  
Calculation Results ◽  
Reduced Density Gradient ◽  
Reduced Density

Methyl-3-aminothiophene-2-carboxylate (matc) is a key intermediate in organic synthesis, medicine, dyes, and pesticides. Single crystal X-ray diffraction analysis reveals that matc crystallizes in the monoclinic crystal system P21/c space group. Three matc molecules in the symmetric unit are crystallographically different and further linked through the N–H⋯O and N–H⋯N hydrogen bond interactions along with weak C–H⋯S and C–H⋯Cg interactions, which is verified by the three-dimensional Hirshfeld surface, two-dimensional fingerprint plot, and reduced density gradient (RDG) analysis. The interaction energies within crystal packing are visualized through dispersion, electrostatic, and total energies using three-dimensional energy-framework analyses. The dispersion energy dominates in crystal packing. To better understand the properties of matc, electrostatic potential (ESP) and frontier molecular orbitals (FMO) were also calculated and discussed. Experimental and calculation results suggested that amino and carboxyl groups can participate in various inter- and intra-interactions.

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