Mechanical properties of spider-web hierarchical honeycombs subjected to out-of-plane impact loading

2018 ◽  
Vol 22 (3) ◽  
pp. 771-796 ◽  
Author(s):  
Qiang He ◽  
Jun Feng ◽  
Yunjiang Chen ◽  
Honggen Zhou
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Structural Parameters ◽  
Element Model ◽  
Spider Web ◽  
Crushing Force ◽  
Out Of Plane ◽  
Structural Variables ◽  
New Type ◽  
Deformation Patterns

Spider-web hierarchy can be introduced by adding smaller hexagons at the centers of original cells in an underlying hexagonal network and connecting the adjacent vertices by straight beams. To examine the out-of-plane crashworthiness of this new type of hierarchical honeycomb concept, a finite element model is established and validated by existing theoretical and experimental results. Then, a parametric study on structural variables [Formula: see text] and [Formula: see text] was carried out with three different densities. The mechanical properties of hierarchical honeycombs are also compared with that of regular honeycombs. The research results show that the deformation patterns of hierarchical honeycombs can be divided into three categories. The energy absorption capability can be controlled effectively by proper adjustment of the hierarchical structural parameters. The specific energy absorption per unit mass ([Formula: see text]) of first-order spider-web hierarchical honeycomb with [Formula: see text] and second-order spider-web hierarchical honeycomb with [Formula: see text] and [Formula: see text] increases by 62.1% and 82.4%, respectively. Meanwhile, the spider-web hierarchical characteristics have less influence on the corresponding Peak Crushing Force ( PCF). Further, the mean crushing force is derived by dividing the profile into basic angle elements based on the Simplified Super Folding Element (SSFE) method. The theoretical calculation is in good agreement with the simulation results as the spider-web hierarchical honeycombs deform in Mode I. These results can provide valuable suggestions in the study and design of the new type hierarchical honeycombs.

Dynamic Characteristics Analysis of Cable-Rib Tension Deployable Antenna

2016 ◽  
Author(s):  
Liu Ruiwei ◽  
Hongwei Guo ◽  
Zhang Qinghua ◽  
Rongqiang Liu ◽  
Tang Dewei
Keyword(s):  
Dynamic Characteristics ◽  
Structural Parameters ◽  
Element Model ◽  
Structure Design ◽  
Antenna Structure ◽  
Characteristics Analysis ◽  
New Type ◽  
Dynamic Characteristics Analysis ◽  
The Finite Element Model ◽  
Weight Dynamic

Balancing stiffness and weight is of substantial importance for antenna structure design. Conventional fold-rib antennas need sufficient weight to meet stiffness requirements. To address this issue, this paper proposes a new type of cable-rib tension deployable antenna that consists of six radial rib deployment mechanisms, numerous tensioned cables, and a mesh reflective surface. The primary innovation of this study is the application of numerous tensioned cables instead of metal materials to enhance the stiffness of the entire antenna while ensuring relatively less weight. Dynamic characteristics were analyzed to optimize the weight and stiffness of the antenna with the finite element model by subspace method. The first six orders of natural frequencies and corresponding vibration modes of the antenna structure are obtained. In addition, the effects of structural parameters on natural frequency are studied, and a method to improve the rigidity of the deployable antenna structure is proposed.

scholarly journals Experimental and FEM Research on Airport Cement Concrete Direct-Thickening Double-Deck Pavement Slabs under Aircraft Single-Wheel Dynamic Loads

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Qingkun Yu ◽  
Liangcai Cai ◽  
Jianwu Wang
Keyword(s):  
Mechanical Properties ◽  
Structural Parameters ◽  
Element Model ◽  
Tension Stress ◽  
Cement Concrete ◽  
Wheel Load ◽  
Critical Position ◽  
Ansys Simulation ◽  
Longitudinal Edge ◽  
Airport Runway

The wide-use airport cement concrete direct-thickening double-deck pavement slabs (ACCDDPS) were selected as the research object to study their mechanical properties. The airport runway simulation test station (ARSTS) was used to conduct indoor tests to demonstrate the distribution of tension stress at the bottom of slabs and slabs deflection. Furthermore, ANSYS software was applied to establish finite element model (FEM) of ACCDDPS and analyze the mechanical laws under different loads. The indoor tests results are in good agreement with the ANSYS simulation results, and some consistent conclusions can be obtained that the maximum tension stress increases with wheel load, and the slab middle of the longitudinal edge is a critical position. In addition, we studied the influence of covered layer thickness, elastic modulus, and slab size on pavement slab mechanical properties by ANSYS, and we concluded that although the structural parameters are different, the critical position of ACCDDPS is still in the middle of the longitudinal edge. However, for the covered layer and the original surface layer, the law that the tension stress values vary with the structural parameters is different, but the maximum deflection value is about 0.1.

Prediction of Mechanical Properties of the Cancellous Bone of the Mandibular Condyle

2003 ◽  
Vol 82 (10) ◽  
pp. 819-823 ◽  
Author(s):  
L.J. van Ruijven ◽  
E.B.W. Giesen ◽  
M. Farella ◽  
T.M.G.J. van Eijden
Keyword(s):  
Mechanical Properties ◽  
Cancellous Bone ◽  
Volume Fraction ◽  
Bone Structure ◽  
Structural Parameters ◽  
Mandibular Condyle ◽  
Element Model ◽  
Micro Computed Tomography ◽  
Bone Volume Fraction ◽  
Apparent Stiffness

The mechanical properties of cancellous bone depend on the bone structure. The present study examined the extent to which the apparent stiffness of the cancellous bone of the human mandibular condyle can be predicted from its structure. Two models were compared. The first, a structure model, used structural parameters such as bone volume fraction and anisotropy to estimate the apparent stiffness. The second was a finite element model (FEM) of the cancellous bone. The bone structure was characterized by micro-computed tomography. The calculated stiffnesses of 24 bone samples were compared with measured stiffnesses. Both models could predict 89% of the variation in the measured stiffnesses. From the stiffness approximated by FEM in combination with the measured stiffness, the stiffness of the bone tissue was estimated to be 11.1 ± 3.2 GPa. It was concluded that both models could predict the stiffness of cancellous bone with adequate accuracy.

scholarly journals Finite Element Modelling Approach for Progressive Crushing of Composite Tubular Absorbers in LS-DYNA: Review and Findings

2021 ◽  
Vol 6 (1) ◽  
pp. 11
Author(s):  
Ali Rabiee ◽  
Hessam Ghasemnejad
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Low Cost ◽  
Peak Load ◽  
Experimental Studies ◽  
Single Layer ◽  
Element Model ◽  
Point Of View ◽  
Element Formulation ◽  
Crushing Force

Robust finite element models are utilised for their ability to predict simple to complex mechanical behaviour under certain conditions at a very low cost compared to experimental studies, as this reduces the need for physical prototypes while allowing for the optimisation of components. In this paper, various parameters in finite element techniques were reviewed to simulate the crushing behaviour of glass/epoxy tubes with different material models, mesh sizes, failure trigger mechanisms, element formulation, contact definitions, single and various numbers of shells and delamination modelling. Six different modelling approaches, namely, a single-layer approach and a multi-layer approach, were employed with 2, 3, 4, 6, and 12 shells. In experimental studies, 12 plies were used to fabricate a 3 mm wall thickness GFRP specimen, and the numerical results were compared with experimental data. This was achieved by carefully calibrating the values of certain parameters used in defining the above parameters to predict the behaviour and energy absorption response of the finite element model against initial failure peak load (stiffness) and the mean crushing force. In each case, the results were compared with each other, including experimental and computational costs. The decision was made from an engineering point of view, which means compromising accuracy for computational efficiency. The aim is to develop an FEM that can predict energy absorption capability with a higher level of accuracy, around 5% error, than the experimental studies.

Fabrication and mechanical properties of three-dimensional enhanced lattice truss sandwich structures

2018 ◽  
Vol 22 (5) ◽  
pp. 1594-1611 ◽  
Author(s):  
Wen Yang ◽  
Jian Xiong ◽  
Li-Jia Feng ◽  
Chong Pei ◽  
Lin-Zhi Wu
Keyword(s):  
Mechanical Properties ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Truss Structures ◽  
Unit Cell Size ◽  
Out Of Plane ◽  
Parent Alloy ◽  
Shear Characteristics ◽  
New Type ◽  
Alloy Properties

Topological-reinforcement and material-strengthening were used and employed to improve the mechanical properties of lattice truss sandwich structures. This new type of three-dimensional aluminum alloy lattice truss (named enhanced lattice truss) sandwich structure, with a relative density ranging from 1.7% to 4.7%, was designed and fabricated by interlocking and vacuum-brazing method. The out-of-plane compression and shear properties of the enhanced lattice truss sandwich structures (both as-brazed and age-hardened cores) were experimentally and analytically investigated. Good correlations between analytical predictions and experiment results were achieved. Experimental results showed that the mechanical properties of the enhanced lattice truss cores were sensitive to the unit-cell size and parent-alloy properties (i.e. inelastic buckling and tangential modulus). The compressive and shear characteristics of enhanced lattice truss sandwich structures were discussed and found superior to competing lattice truss structures in low density area (0.046–0.124 g/cm3) of material property charts. The combination of topological-reinforcement and material-strengthening provided a way to achieve lightweight sandwich structures with high specific strengths and low densities.

Bi-tubular corrugated composite conical–cylindrical tube for energy absorption in axial and oblique loading: Analysis and optimization

2020 ◽  
Vol 54 (18) ◽  
pp. 2399-2432 ◽  
Author(s):  
Amirreza Sadighi ◽  
Mahshid Mahbod ◽  
Masoud Asgari
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Cylindrical Tube ◽  
Element Model ◽  
Geometrical Parameters ◽  
Compression Tests ◽  
Static Compression ◽  
Optimization Study ◽  
Crushing Force ◽  
Optimum Model

In this paper, a new bi-tubular corrugated composite tube, consisting of inner and outer cylindrical and conical tubes is proposed. Different models with various geometrical parameters including the radius of curvatures and their numbers are considered and studied numerically in axial and oblique crushing in order to achieve favorable crashworthiness parameters. Moreover, quasi-static compression tests have been conducted to obtain results in order to validate the finite element model. There has been a sensible agreement between the numerical results and experimental data. Finite element models are also validated using the analytical solutions for both straight and corrugated composite tubes. Regardless of the number and radius of curvatures, as the crashworthiness of bi-tubular corrugated structures both in axial and oblique crushing is investigated and compared with their single-wall and bi-tubular straight peers, a considerable improvement is achieved in all crashworthiness parameters, including desirable increase in specific energy absorption, favorable reduction in peak force, and consequently a beneficial rise in crushing force efficiency. In addition, an optimization study using a suitable multi-objective function is done to choose the best model among the existing models, in addition to finding an optimum model via genetic algorithm. In the next step, a parametric study is conducted on the best model to inspect how well it undergoes oblique crushing at different angles. Finally, this best model and two other candidates have been chosen to investigate the effect of using foams and then the energy absorption capability of the empty and foam-filled tubes has been compared.

Effect of core corrugation angle on static compression of self-reinforced PP sandwich panels and bending energy absorption of sandwich beams

2020 ◽  
pp. 002199832096053
Author(s):  
Ali Imran ◽  
Shijie Qi ◽  
Pengcheng Shi ◽  
Muhammad Imran ◽  
Dong Liu ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Structural Parameters ◽  
Maximum Energy ◽  
Absorption Capacity ◽  
Ex Situ ◽  
Static Compression ◽  
Reinforced Polymer ◽  
Optimization Study ◽  
Out Of Plane ◽  
Optimal Stiffness

The structural weight of an electric vehicle and its material’s recyclability are the important parameters to optimize the overall cost as well as the mileage of a vehicle. Self-reinforced polymer composites (SRCs) can be potentially used for these applications because of their 100% recyclability as compared with multicomponent traditional epoxy matrix based fibre reinforced composites. In case of SRCs the fibres and matrix are synthesized from same family of polymers. An optimization study is required based on integration of material and structural parameters to reduced overall weight of the vehicles while keeping the strength up to the safety mark. We fabricated self-reinforced polypropylene (SrPP) sandwich structures through an ex-situ consolidation based fabrication method. An FEA based study was conducted to optimize the effect of core corrugation angle of sandwiched structures on out of plane compressive strength and flexural strength of SrPP sandwiched beams. The finite element study was preferred in order to save the experimental cost. Beams with 60° core corrugation angle have optimal flexural properties. The sandwiched panels with 45° corrugated core exhibited optimal stiffness while maximum energy absorption capacity was shown with 60° corrugated core sandwiched structures.

Impact Analysis of Different Cable Types on Saddle-Shaped Cable-Net in Construction Process

2012 ◽  
Vol 479-481 ◽  
pp. 190-193
Author(s):  
Zhan Sheng Liu ◽  
Ran Zhang
Keyword(s):  
Mechanical Properties ◽  
Impact Analysis ◽  
Steel Wire ◽  
Steel Structure ◽  
Element Model ◽  
Wire Rope ◽  
Construction Process ◽  
New Type ◽  
Prestressed Steel Structure ◽  
The Impact

Cable is widely used in the actual project of prestressed steel structure for its mechanical properties can be fully used. Saddle-shaped cable net is a new type of large-span prestressed structure, but there is little study on the impact of different cable types on the mechanical properties of saddle-shaped cable net during the construction. In order to meet the thought of integration of design and construction, a finite element model of saddle-shaped cable net has been established. The four types of cables such as semi-parallel steel tendon cable, steel wire rope cable, steel strand cable and full-locked coil rope are chosen. The impact on mechanical properties of the structure was analyzed by different cable types.

DYNAMIC CRUSHING SIMULATION OF METALLIC FOAMS WITH RESPECT TO DEFORMATION AND ENERGY ABSORPTION

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5381-5387
Author(s):  
Y. F. ZHANG ◽  
L. M. ZHAO
Keyword(s):  
Energy Absorption ◽  
Deformation Rate ◽  
Element Model ◽  
Pore Fluid ◽  
Two Dimensional ◽  
Metallic Foams ◽  
Fluid Loading ◽  
Mass Spring ◽  
Nonlinear Elastic ◽  
Deformation Patterns

In this paper, a two-dimensional nonlinear elastic-plastic mass-spring-damper-rod element model is employed to simulate the crush behavior of metallic foams. The density heterogeneity and pore fluid of metallic foams are considered. The metallic foams are compressed by applying a planar pulse loading or by giving a deformation rate. Several numerical results show the deformation patterns and the energy absorption regime of metallic foams under crush loading. The influence of heterogeneous density, cell fluid, loading intensity, deformation rate on the deformation and the energy absorption of metallic foams is assessed.

scholarly journals Crashworthiness Optimization Design of Aluminum Alloy Thin-Walled Triangle Column Based on Bioinspired Strategy

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 666
Author(s):  
Kangjie Li ◽  
Yixiong Feng ◽  
Yicong Gao ◽  
Hao Zheng ◽  
Hao Qiu
Keyword(s):  
Aluminum Alloy ◽  
Energy Absorption ◽  
Optimization Design ◽  
Element Model ◽  
Design Strategy ◽  
Parameter Study ◽  
Bioinspired Design ◽  
Thin Walled Structures ◽  
Out Of Plane ◽  
Thin Walled

Aluminum alloy thin-walled structures have been well used in applications of energy absorption. In the present work, a bioinspired design strategy for aluminum alloy thin-walled structures is proposed to improve the performance of out-of-plane crashworthiness by altering the material distribution. According to the proposed strategy, a novel fractal thin-walled triangle column (FTTC) is designed, which is composed by iteratively applying the affine transformation of a base triangle up to 2nd-order. The finite element model is established to investigate the out-of-plane crashworthiness of FTTC and validated by experiment results. The numerical analysis of the crashworthiness of FTTC with different fractal orders (0th, 1st and 2nd) are performed, and the results show that 1st- and 2nd-order FTTC enhance the energy absorption of structures and crush force efficiency. In particular, 2nd-order FTTC has better energy absorption ability due to the optimal distribution of materials, which are efficiently organized by the proposed bioinspired design strategy. In addition, a parameter study is performed to investigate the effect of FTTC geometric details on the crushing procedure. The collapse mode shows that it tends to change from unstable to stable with the increase in thickness and side length and the decrease in height. Moreover, a positive relevant relationship is identified between the thickness and the crashworthiness for FTTC.

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