scholarly journals Buckling Analysis of a Large Shelter with Composites

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7196
Author(s):  
Sheldon Wang ◽  
Jianyao Mou
Keyword(s):  
Finite Element ◽  
Structural Model ◽  
Nonlinear Finite Element ◽  
Orthotropic Materials ◽  
Finite Element Analyses ◽  
Three Point Bending ◽  
Critical Issues ◽  
Proper Design ◽  
Linear And Nonlinear ◽  
Simulation Results

We present here linear and nonlinear finite element analyses of a newly designed deployable rapid assembly shelter (DRASH J) manufactured by DHS Systems. The structural analysis is carried out in three stages. Firstly, single composite tubes (struts) under three-point bending are modeled with five layers of orthotropic materials in three different orientations and the simulation results are compared with the actual test data for validation. Secondly, a comprehensive structural model for the entire shelter is constructed with the consideration of two types of strut scissor points, namely natural and forced scissor (crossing) points, as well as partial-fixed hub joints, which allow rotations along individual hub slots (grooves). Finally, a simplified structural model is created by introducing fixed joints for the scissor points as well as rigid links for the hubs. With sufficient verifications with experiments and different modeling methods, linear and nonlinear finite element analyses are then carried out for both the comprehensive and simplified shelter models. Based on the simulation results, we are able to identify a few critical issues pertaining to proper design and modifications of such shelter systems, such as various end wall supports pertaining to the overall structural stability.

Experimental and Numerical Analyses of the Lightweight Potential for Hybrid Thin-Walled Members

2015 ◽  
Vol 825-826 ◽  
pp. 732-740 ◽  
Author(s):  
Josef Denk ◽  
Sergej Diel ◽  
Otto Huber
Keyword(s):  
Finite Element ◽  
Epoxy Resin ◽  
Weight Reduction ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Collapse Load ◽  
Three Point Bending ◽  
Two Component ◽  
Glass Foam ◽  
Thin Walled

Within this study, the lightweight potential of thin-walled closed hat members, partially supported by hollow cores, consisting of glass foam granulate and a two component epoxy resin, is investigated. Nonlinear finite element analyses are applied to simulate the behavior under quasi-static three-point bending and to find out the lightweight potential. The simulations are validated by experiments on thin-walled side members of the chassis of a recreational vehicle with and without supporting cores. The results show a significant potential for weight reduction by using supporting cores. Related to the weight (Fmax/Fg), experiments have shown that the collapse load is 38 % larger in comparison to thin-walled members without supporting cores.

Design of flexure revolute joint based on compliance and stiffness ellipsoids

2021 ◽  
pp. 095441002110169
Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson
Keyword(s):  
Finite Element ◽  
Single Point ◽  
Synthesis Method ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Rotational Stiffness ◽  
Rotational Angle ◽  
Parameterized Model ◽  
Flexure Joints ◽  
Translational Stiffness

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.

Numerical Investigation on Behaviors of Stiffened Large Suction Cap for Offshore Suction Cofferdam

2020 ◽  
Author(s):  
Jeongsoo Kim ◽  
Yeon-Ju Jeong ◽  
Min-Su Park ◽  
Sunghoon Song
Keyword(s):  
Finite Element ◽  
Structural Design ◽  
Nonlinear Finite Element ◽  
Finite Element Models ◽  
Suction Pressure ◽  
Sheet Pile ◽  
Large Size ◽  
Critical Issues ◽  
Stress And Deformation ◽  
Pile Type

Abstract This study introduces a large offshore cofferdam installed by suction, unlike conventional ones such as a sheet-pile type, and proposes an effective suction cap for the cofferdam. In structural design view of the cofferdam, there are several critical issues due to its large size. This study conducted structural analyses of stiffened caps for large offshore suction cofferdam using fully nonlinear finite element models, and analyzed changes in behaviors of the cap due to stiffener arrangements to provide design insights. For finite element models, the diameter and the thickness of the suction cap (circular plate only) are 20m and 0.07m, respectively. Suction pressure on the cap was assumed to be 100kPa, all parts of the cofferdam except the cap are considered as boundary conditions. By investigating conventional suction anchors, several stiffener arrangement patterns on the cap of suction cofferdam were derived, and each arrangement was estimated by comparing stress and deformation of the cap. Also, reaction distributions on the edge of the cap were investigated to analyze effects of the stiffener arrangement on the interface behaviors between cap and cofferdam.

ESTABLISHMENT AND APPLICATION OF LOWER LIMB FINITE ELEMENT MODEL BASED ON MUSCLE GROUPS

2018 ◽  
Vol 18 (08) ◽  
pp. 1840024
Author(s):  
MONAN WANG ◽  
RONGPENG LI ◽  
JUNTONG JING
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Finite Element Model ◽  
Lower Limb ◽  
Element Model ◽  
Upper And Lower Bounds ◽  
Three Point Bending ◽  
Living Body ◽  
Prosthetic Socket ◽  
Simulation Results

Living body or corpse could be replaced with the virtual human tissue model for biomechanical experimental study, which effectively avoids the non-reusability, great social controversy, huge costs and difficulty in extracting parameters, and finally, the accurate analysis results are obtained. Unlike the previous lower limb models, the finite element models of hip and thigh were established based on the concept of muscle group in this paper. The cortical bones of hip bone and femur were set as *MAT_PIECEWISE_LINEAR_ PLASTICITY. The material of cancellous bone was set as *MAT_ELASTIC_PLASTIC_ WITH_DAMAGE_FAILURE. The material of articular cartilage was set as *MAT_ISOTROPIC_ELASTIC. The materials of muscle and fat were set as *MAT_VISCOELASTIC. The accuracy of the finite element model was verified by dynamic three-point bending experiment of the thighs. Mechanical simulation was carried out to the stump-prosthetic socket and the comfort of socks by the established model. The simulation results were all between the upper and lower bounds of the experimental results in the dynamic three-point bending experiment of the thighs where the loads were separately applied to one-third of the distal end of thighs and the middle part of thighs. The simulation results of the stump-prosthetic socket example show that the optimal elastic modulus of silicone pad is 2.5[Formula: see text]MPa. Simulation results of socks comfort show that the distribution of stress and deformation of the anterior and posterior thighs is different when the human lower limbs are in stockings. The established simulation model meets the accuracy requirement and can replace the living body or corpse to carry out biomechanical experimental study. The finite element simulation results converge, and the time to complete a finite element calculation is less than or equal to 10[Formula: see text]min.

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