In-Plane Quasi-Static Crushing of Cissoidal Hexagonal Honeycomb Cores

2012 ◽  
Vol 446-449 ◽  
pp. 3736-3739 ◽  
Author(s):  
De Qiang Sun ◽  
Miao Liu ◽  
Ying Xue Zhu
Keyword(s):  
Fe Simulation ◽  
Edge Length ◽  
Mechanical Behaviors ◽  
Response Curves ◽  
Plateau Stress ◽  
Deformation Processes ◽  
Simulation Results ◽  
Data Tables ◽  
Honeycomb Cores ◽  
Force Displacement

The mechanical behaviors of cissoidal hexagonal cores (CHCs) are investigated by using the finite element (FE) simulations under the in-plane quasi-static crushing loadings. The calculated deformation processes, response curves and values of plateau stress are presented in the forms of diagrams, force-displacement curves or data tables, respectively. The influences of ratio of cell wall thickness to edge length and expanding angle on the quasi-static plateau stress are discussed in detail. The empirical expressions of quasi-static plateau stress in terms of configuration parameters are given based on the FE simulation results.

In-Plane Crushing of Triangular Honeycomb Cores, Part I: Under Quasi-Static Loadings

2012 ◽  
Vol 476-478 ◽  
pp. 2501-2504
Author(s):  
De Qiang Sun ◽  
Yan Feng Guo ◽  
Guo Tu Xu
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Deformation Mode ◽  
Edge Length ◽  
Cell Wall Thickness ◽  
Response Curves ◽  
Plateau Stress ◽  
Honeycomb Cores ◽  
Force Displacement ◽  
Scale Coefficient

Mechanical behaviors of triangular honeycombs cores (THCs) are investigated by using the finite element (FE) simulations under the in-plane quasi-static crushing loadings. The deformation process is described in the form of response curves and deformation mode diagrams. The force-displacement curves include four deformation regimes with distinct characteristics. The quasi-static plateau stresses are calculated for the THCs with different configuration parameters. The influences of ratio of cell wall thickness to edge length and expanding angle on the quasi-static plateau stress are discussed in detail. The quasi-static plateau stress is proportional to the relative density of THCs and the expanding angle determines the scale coefficient. The empirical formula of quasi-static plateau stress in terms of ratio of cell wall thickness to edge length and expanding angle is given based on the FE simulation results.

In-Plane Crushing of Square Honeycomb Cores, Part I: Mechanical Behaviors

2012 ◽  
Vol 170-173 ◽  
pp. 3220-3223 ◽  
Author(s):  
De Qiang Sun ◽  
Wen Ting Cao ◽  
Meng Cai
Keyword(s):  
Finite Element ◽  
Impact Velocity ◽  
Inertia Effect ◽  
Mechanical Behaviors ◽  
Empirical Formulas ◽  
Plateau Stress ◽  
Honeycomb Cores ◽  
Dynamic Enhancement ◽  
Deformation Modes ◽  
Force Displacement

Mechanical behaviors of square honeycombs cores (SHCs) are investigated by using the finite element (FE) simulations under the in-plane dynamic crushing loadings. With the increasing impact velocities, different deformation modes are observed. The force-displacement curves include four regimes with distinct characteristics. The plateau stresses are calculated for the SHCs with different configuration parameters. The dynamic plateau stress is the sum of the static plateau stress and the dynamic enhancement due to the inertia effect. The static plateau stress is proportional to the relative density of SHCs. The dynamic enhancement stress is proportional to the square of impact velocity and the relation coefficient depends on the configuration parameters. The empirical formulas of dynamic plateau stress in terms of configuration parameters and impact velocity are given.

scholarly journals Zero Watermarking for the TIN DEM Data Based on the Edge Length

2021 ◽  
Vol 10 (8) ◽  
pp. 559
Author(s):  
Qifei Zhou ◽  
Changqing Zhu ◽  
Na Ren
Keyword(s):  
Edge Length ◽  
Majority Voting ◽  
Data Simulation ◽  
Triangulated Irregular Network ◽  
Digital Elevation ◽  
Crucial Problem ◽  
Simulation Results ◽  
Elevation Model ◽  
Zero Watermarking ◽  
Voting Mechanism

How to keep the fidelity of the digital elevation model (DEM) data is a crucial problem in the current watermarking research, as the watermarked DEM data need to preserve their accuracy. We proposed a zero watermarking method for the triangulated irregular network (TIN) DEM data. It takes full advantage of the characteristics of the edge length in the TIN DEM data. First, the radio of the edge lengths is quantified to the watermark index, and then the comparison of the edge lengths is quantified to the watermark bit. Finally, the watermark is constructed by combing the watermark bits according to the watermark indices with the help of the majority voting mechanism. In the method, the TIN DEM data are only used to construct the watermark, not to be embedded by the watermark. Therefore, the data quality is preserved to the greatest extent. Experiments verify the theoretical achievements of this method and demonstrate the method is lossless to the TIN DEM data. Simulation results also show that the method has good robustness on translation, rotation, scaling, and cropping attacks.

Research into Contact Interaction of an Elastic Tool during Rotational Pattern Cutting of Sheet Parts

2016 ◽  
Vol 685 ◽  
pp. 408-412 ◽  
Author(s):  
E.G. Gromova ◽  
A.G. Bakanova
Keyword(s):  
Finite Element ◽  
Mathematical Simulation ◽  
Elastic Medium ◽  
Design Process ◽  
Experimental Research ◽  
Simulation Method ◽  
Medium Pressure ◽  
Element Simulation ◽  
Deformation Processes ◽  
Simulation Results

The paper describes a method of pattern cutting of sheet articles using the elastic medium pressure. Research works have been conducted into feasibility of the suggested pattern cutting using finite element simulation method. The experimental research was conducted into deformation processes during rotational separating stamping of sheet articles by means of elastic medium pressure so that to confirm relevance of the mathematical simulation results. The optimum design process parameter value combinations have been determined for implementing the rotary pattern cutting process.

Bearing Capacity Analysis on Slotted End Plate Connection Joints of Different Types

2012 ◽  
Vol 166-169 ◽  
pp. 764-769
Author(s):  
Ruo Hui Qiang ◽  
Ming Zhou Su ◽  
Junfen Yang ◽  
Jinbo Cui
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Great Influence ◽  
Mechanical Behaviors ◽  
End Plate ◽  
Different Types ◽  
Plastic Stage ◽  
Plate Connection ◽  
Force Displacement ◽  
Main Factor

Four different types of full-scale slotted end plate (SEP) connection joints are tested to determine their failure modes and damage mechanisms under ultimate loading. Researches on mechanical behaviors of I-type, T-type, U-type and Groove SEP connection joints bearing compression are studied, which also analyze their force-displacement behaviors and developing processes of deformation and strain. The results show that the bearing capacities of I, grooved, T and U types SEP connections are increased gradually, which indicate the SEP’s type has great influence on the ultimate strength of joints. The instability of SEP is the main factor to cause the loss of bearing capacity of the connection, which is shown through the development of strain, that SEP enters into plastic stage and the other regions still are elastic.

General Equations of a Helical Spring With a Cup Damper and Static Verification

1997 ◽  
Vol 119 (2) ◽  
pp. 319-326 ◽  
Author(s):  
Ming Hsun Wu ◽  
Jing Yuan Ho ◽  
Wensyang Hsu
Keyword(s):  
Experimental Data ◽  
Pitch Angle ◽  
Equations Of Motion ◽  
Maximum Error ◽  
Dynamic Equations ◽  
Helical Spring ◽  
Static Force ◽  
Static Verification ◽  
Simulation Results ◽  
Force Displacement

In this study, we derive the general equations of motion for the helical spring with a cup damper by considering the damper’s dilation and varying pitch angle of the helical spring. These dynamic equations are simplified to correlate with previous models. The static force-displacement relation is also derived. The extra stiffness due to the damper’s dilation considered in the force-displacement relation is the first such modeling in this area. In addition, a method is presented to predict the compressing spring’s coil close length and is then verified by experimental data. Moreover, the simulation results of the static force-displacement relation are found to correspond to the experimental data. The maximum error is around 0.6 percent.

Dynamic analysis of elastically and plastically graded spherical and cylindrical contact

2019 ◽  
Vol 233 (11) ◽  
pp. 1712-1728 ◽  
Author(s):  
Tamonash Jana ◽  
Anirban Mitra ◽  
Prasanta Sahoo
Keyword(s):  
Dynamic Analysis ◽  
Material Properties ◽  
Static Force ◽  
Contact Interface ◽  
Response Curves ◽  
Initial Displacement ◽  
Finite Element Software ◽  
Displacement Behavior ◽  
Force Displacement ◽  
Plastically Graded

A dynamic analysis of a hemispherical and cylindrical contact, material properties of which are graded elastically and plastically along the radius, is presented. The static force–displacement behavior of a hemisphere and a semi-cylinder in contact with a rigid flat is obtained using finite element software. The force–displacement is used in a further dynamic analysis for undamped-free as well as for forced-damped vibration of the contact interface. For the undamped free vibration, variation of natural frequency w.r.t. initial displacement is furnished for different values of elastic and plastic gradation parameter. In addition, variation of maximum initial displacement for contact loss is also demonstrated. The forced-damped vibration characteristics of the spherical and cylindrical contact interfaces are presented in the form of frequency response curves with jump up and jump down frequencies. Spherical and cylindrical contact interfaces are found to exhibit softening and hardening type nonlinearity, respectively.

In-Plane Crushing of Square Honeycomb Cores, Part II: Energy Absorption and Cushioning Optimization

2012 ◽  
Vol 170-173 ◽  
pp. 3237-3240
Author(s):  
De Qiang Sun ◽  
Zu Yong Jiang ◽  
Yan Bin Wei
Keyword(s):  
Energy Absorption ◽  
Impact Velocity ◽  
Physical Analysis ◽  
Fe Model ◽  
Mechanical Parameters ◽  
Empirical Formulas ◽  
Plateau Stress ◽  
Optimal Energy ◽  
Honeycomb Cores ◽  
Dynamic Densification

The finite element (FE) model designed in Part I is used to obtain the cushioning mechanical parameters of square honeycomb cores (SHCs) under in-plane dynamic loadings. A simplified energy absorption model is proposed to evaluate the energy absorption performance of SHCs, which shows that the optimal energy absorption per unit volume is related to dynamic plateau stress and dynamic densification strain that are affected by configuration parameters and impact velocity. The optimal energy absorption efficiency is the reciprocal of dynamic densification strain. The dynamic plateau stress has been discussed in Part I. For SHCs, the dynamic densification strain is independent of impact velocity and determined by configuration parameters. The empirical formulas of cushioning mechanical parameters are derived from physical analysis of FE results. Based on these empirical formulas, the practical cushioning optimization algorithm is presented.

Comparing Study on Real Drawbead and Equivalent Drawbead Based on Finite Element Analysis

2012 ◽  
Vol 430-432 ◽  
pp. 1056-1059
Author(s):  
Xiao Gang Qiu ◽  
Hao Huang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deformation Behavior ◽  
Fe Simulation ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
The Real ◽  
Finite Element Software ◽  
Simulation Results ◽  
Virtual Velocity

The dynamic explicit finite element software DYNAFORM was used to simulate the real and equivalent drawbead model. Analyzed the influence of the blank hold force (BHF) and virtual velocity on blank’s deformation behavior after passing through drawbead, compared the results of the FE simulation. The simulation results were confirmed by experiments. The study shows that the equivalent drawbead model can’t simulate the blank’s behavior precisely when it passing the real drawbeads, the effect of BHF on real drawbead model is larger than equal drawbead model; the proper range of virtual velocity was obtained at the same time.

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