On application of catenary principles to sandwich structure design—Sandwich/ catenary hybrid beams under uniformly distributed load

2017 ◽  
Vol 22 (2) ◽  
pp. 127-155
Author(s):  
Jørgen Asbøll Kepler
Keyword(s):  
Sandwich Structure ◽  
Load Transfer ◽  
Equilibrium Shape ◽  
Sandwich Beam ◽  
Structure Design ◽  
Face Sheet ◽  
Elastic Response ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Hybrid Beams

Application of catenary principles to sandwich structure design, whereby one face sheet follows the equilibrium shape of a catenary according to the applied load, is investigated. The difference between load transfer through a sandwich beam and through a catenary is outlined. An initial comparison between an inclined elastic string and a sandwich core under shear deformation provides an indication of the potential stiffness advantages of catenary design. A stiffness comparison is made between an ordinary sandwich beam with thin, parallel face sheets, a catenary suspended by the end-points, and a sandwich/catenary hybrid. It is demonstrated that, for mass parity and a uniformly distributed load, and depending on the constituent materials moduli, the sandwich/catenary hybrid may be designed for superior stiffness. A numerical modeling method is outlined for evaluating the deflection of a catenary, and subsequently expanded to predict deflection of a sandwich/catenary hybrid beam. The method is verified through comparison with experimentally measured deflection. It is demonstrated that first-order shear deformable theory, commonly applied to sandwich structures, is inherently unsuited for describing the elastic response of sandwich/catenary hybrids. For a typical range of face-sheet/core moduli, comparisons of relative stiffness for parallel-face sandwich beams and sandwich/catenary hybrid beams are calculated over a range of core heights, for equivalent core height and equivalent core volume.

scholarly journals Structure design and reliability analysis of Al-Ti lugs

2021 ◽  
Vol 39 (1) ◽  
pp. 1-8
Author(s):  
Yunwen Feng ◽  
Jiale Zhang ◽  
Xiaofeng Xue ◽  
Xiaoping Zhong ◽  
Wei Xie
Keyword(s):  
Reliability Analysis ◽  
Structural Design ◽  
Design Principle ◽  
Load Transfer ◽  
Design Method ◽  
Static Strength ◽  
Structure Design ◽  
Safety Design ◽  
Design Requirements ◽  
Metal Materials

Aircraft lug joint is the key part of load transfer. In order to improve the safety of lug joint, on the premise of meeting the design requirements of static strength and fatigue, the composite connection lug structure design technology of different metal materials is proposed in this paper. Firstly, the damage safety design and life reliability analysis of the lug structure are studied theoretically. Secondly, based on the concept of damage safety design and the design principle of deformation coordination, the design method of composite connection lug with deformation coordination is proposed, and the thickness ratio of single ear is 0.8:1:0.8. Finally, the reliability of the composite lug is analyzed. The results show that the structural design scheme of aluminum-titanium composite ear piece can meet the requirements of static strength and damage tolerance, and compared with the conventional ear structure, the failure probability of structure mission life is greatly reduced when the weight of the composite connection lug is only increased by 4.9%. The proposed method can effectively guide the structural design of composite ear piece.

scholarly journals Effects of additional load at different heights on gait initiation: A statistical parametric mapping of center of pressure and center of mass behavior

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0242892
Author(s):  
Marcus Fraga Vieira ◽  
Fábio Barbosa Rodrigues ◽  
Alfredo de Oliveira Assis ◽  
Eduardo de Mendonça Mesquita ◽  
Thiago Santana Lemes ◽  
...  
Keyword(s):  
Time Series ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Statistical Parametric Mapping ◽  
Gait Initiation ◽  
Experimental Conditions ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Reaction Forces ◽  
Controlled Object

The purpose of this study was to investigate the effects of different vertical positions of an asymmetrical load on the anticipatory postural adjustments phase of gait initiation. Sixty-eight college students (32 males, 36 females; age: 23.65 ± 3.21 years old; weight: 69.98 ± 8.15 kg; height: 1.74 ± 0.08 m) were enrolled in the study. Ground reaction forces and moments were collected using two force platforms. The participants completed three trials under each of the following random conditions: no-load (NL), waist uniformly distributed load (WUD), shoulder uniformly distributed load (SUD), waist stance foot load (WST), shoulder stance foot load (SST), waist swing foot load (WSW), and shoulder swing foot load (SSW). The paired Hotelling’s T-square test was used to compare the experimental conditions. The center of pressure (COP) time series were significantly different for the SUD vs. NL, SST vs. NL, WST vs. NL, and WSW vs. NL comparisons. Significant differences in COP time series were observed for all comparisons between waist vs. shoulder conditions. Overall, these differences were greater when the load was positioned at the shoulders. For the center of mass (COM) time series, significant differences were found for the WUD vs. NL and WSW vs. NL conditions. However, no differences were observed with the load positioned at the shoulders. In conclusion, only asymmetrical loading at the waist produced significant differences, and the higher the extra load, the greater the effects on COP behavior. By contrast, only minor changes were observed in COM behavior, suggesting that the changes in COP (the controller) behavior are adjustments to maintain the COM (controlled object) unaltered.

scholarly journals Theoretical and Numerical Analysis of an Aluminum Foam Sandwich Structure

2020 ◽  
Vol 15 (3) ◽  
pp. 113-124
Author(s):  
Alaa Al-Fatlawi ◽  
Károly Jármai ◽  
György Kovács
Keyword(s):  
Sandwich Structure ◽  
Aluminum Foam ◽  
Face Sheet ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Design Variables ◽  
Reinforced Plastic ◽  
Size Constraints ◽  
Theoretical And Numerical Analysis ◽  
Composite Face

The aim of the research was to develop a new lightweight sandwich structure, which can be used for elements of air containers. The structure consists of aluminum foam core with fiber reinforced composite face-sheets. Nine different laminated glass or/and carbon fiber reinforced plastic face-sheet combinations were investigated. Finite element analysis of the sandwich structures was introduced. Single-objective optimization of the new sandwich structure was achieved for minimal weight. Five design constraints were considered: stiffness of the structure, face-sheet failure, core shear, face-sheet wrinkling, size constraints for design variables. The elaborated composite structure results significant weight savings due to low density.

scholarly journals Analysis of Cantilever Beam Deflection under Uniformly Distributed Load using Artificial Neural Networks

2019 ◽  
Vol 255 ◽  
pp. 06004
Author(s):  
T.M.Y.S Tuan Ya ◽  
Reza Alebrahim ◽  
Nadziim Fitri ◽  
Mahdi Alebrahim
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Cantilever Beam ◽  
Training Data ◽  
Beam Deflection ◽  
Problem Solver ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Non Linear ◽  
Artificial Neural

In this study the deflection of a cantilever beam was simulated under the action of uniformly distributed load. The large deflection of the cantilever beam causes the non-linear behavior of beam. The prupose of this study is to predict the deflection of a cantilever beam using Artificial Neural Networks (ANN). The simulation of the deflection was carried out in MATLAB by using 2-D Finite Element Method (FEM) to collect the training data for the ANN. The predicted data was then verified again through a non linear 2-D geometry problem solver, FEM. Loads in different magnitudes were applied and the non-linear behaviour of the beam was then recorded. It was observed that, there is a close agreement between the predicted data from ANN and the results simulated in the FEM.

scholarly journals Calculation of orthotropic plates for creep taking into account shear deformations

2018 ◽  
Vol 196 ◽  
pp. 01002 ◽  
Author(s):  
Anton Chepurnenko ◽  
Batyr Yazyev ◽  
Angelica Saibel
Keyword(s):  
Differential Equations ◽  
Transverse Shear ◽  
System Of Differential Equations ◽  
Orthotropic Plates ◽  
Shear Deformations ◽  
Tangential Stresses ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Basic Hypothesis

A system of differential equations is obtained for calculating the creep of orthotropic plates taking into account the deformations of the transverse shear. The basic hypothesis is a parabolic change in tangential stresses over the thickness of the plate. An example of the calculation is given for a GRP plate hinged on the contour under the action of a uniformly distributed load.

Deployable Process Analysis of Packaged SMP Sandwich Beam

2010 ◽  
Vol 123-125 ◽  
pp. 943-946 ◽  
Author(s):  
Zheng Fa Li ◽  
Zheng Dao Wang
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Sandwich Structure ◽  
Shape Recovery ◽  
Process Analysis ◽  
Sandwich Beam ◽  
Shape Memory Polymers ◽  
Recovery Stress ◽  
Recovery Response

Shape memory polymers own many advantages compared with traditional shape memory alloys or ceramics. In order to improve their shape recovery stress and realize a stable recovery response during the deployable process, the structure of SMP sandwich beam composed of two metallic skin and one SMP core is considered. The recovery behaviors of pure SMP and SMP beams reinforced by one-layer metallic skin are also discussed for comparison. The results confirm that the deployable properties of SMP matrix can be significantly improved by using sandwich structure.

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