Experimental and Optimization Study of Compression Behavior of Sandwich Panels with New Symmetric Lattice Cores

2021 ◽  
pp. 146442072110497
Author(s):  
Hossein Norouzi ◽  
Masoud Mahmoodi
Keyword(s):  
Sandwich Panel ◽  
Sandwich Panels ◽  
Weight Ratio ◽  
Quantitative Relationship ◽  
Compression Tests ◽  
Design Variables ◽  
Optimization Study ◽  
Predicted Values ◽  
Lattice Core ◽  
Initial Peak

The paper presents a novel core design for sandwich panels and conducts an experiment to determine whether the mechanical strength of symmetric aluminum lattice core sandwich panels can be improved. Both Design of Experiments (DOE) and Response Surface Methodology (Box-Behnken) were used to establish a quantitative relationship between the strength-to-weight ratio and the input parameters. The thickness of the sheet, the height of sandwich panels, and the width of the seat were all considered design variables to achieve the optimal state. The maximum Initial Peak Crushing Forces (IPCF) were then determined using quasi-static axial flatwise compression tests. This study found that the model's predicted values were consistent with the experimental results. As a result, the parameters were optimized using the Design-Expert software to maximize the initial peak force while minimizing the weight. The results were validated using the Genetic Algorithm, NSGA2, and LINGO. The results indicated that the height of the sandwich panel and the thickness of the sheet had the most significant impact on the maximum force and panel weight. To this end, it is concluded that introducing a novel core design for the sandwich panel, utilizing a suitable Snap-Fitting method for attaching lattice parts rather than using a paste, and finally optimizing the core were the primary reasons for achieving this level of strength.

Performance assessment of rigid polyurethane foam core sandwich panels under blast loading

2019 ◽  
Vol 11 (1) ◽  
pp. 109-130 ◽  
Author(s):  
Hosein Andami ◽  
Hamid Toopchi-Nezhad
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Polyurethane Foam ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Element Model ◽  
Polyurethane Foams ◽  
Compression Tests ◽  
Foam Layer ◽  
The Finite Element Model

The performance of rigid polyurethane foams, as an energy absorbent core of sandwich panels covered with two exterior steel sheets, was investigated numerically through finite element methods. After verifying the finite element model, numerical studies were conducted to investigate the role of thickness and density of the foam layer in the response behavior of sandwich panels under blast loads. A set of cylindrical polyurethane foam specimens were manufactured at five different nominal densities, 90, 140, 175, 220, and 250 kg/m3, and their stress–strain curves were evaluated using uniaxial compression tests. The test data were then employed to define characteristics of the polyurethane foams in the finite element model. Based on the results of finite element analysis runs, the optimum density of the foam layer was determined by assessing two response parameters including the peak pressure transmitted to the back face of the foam layer and the maximum deflection of sandwich panel. These response parameters were found to be affected differently by variations in the density of the foam layer within the panel. An increase in the thickness of the foam layer, to a certain extent, was found to be beneficial to the mitigation capability of sandwich panel.

Experimental and numerical investigation on bending and compressive behavior of carbon-epoxy sandwich panel with novel M-shaped core

2022 ◽  
pp. 089270572110466
Author(s):  
Himan Khaledi ◽  
Yasser Rostamiyan
Keyword(s):  
Polyurethane Foam ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Bending Tests ◽  
Three Point Bending ◽  
Composite Sandwich ◽  
Compressive Loads ◽  
Lattice Core ◽  
Force Displacement ◽  
Good Agreement

Present paper has experimentally and numerically investigated the mechanical behavior of composite sandwich panel with novel M-shaped lattice core subjected to three-point bending and compressive loads. For this purpose, a composite sandwich panel with M-shaped core made of carbon fiber has been fabricated in this experiment. In order to fabricate the sandwich panels, the vacuum assisted resin transfer molding (VARTM) has been used to achieve a laminate without any fault. Afterward, polyurethane foam with density of 80 kg/m3 has been injected into the core of the sandwich panel. Then, a unique design was presented to sandwich panel cores. The study of force-displacement curves obtained from sandwich panel compression and three-point bending tests, showed that an optimum mechanical strength with a considerable lightweight. It should be noted that the experimental data was compared to numerical simulation in ABAQUS software. According to the results, polyurethane foam has improved the flexural strength of sandwich panels by 14% while this improvement for compressive strength is equal to 23%. As well as, it turned out that numerical results are in good agreement with experimental ones and make it possible to use simulation instead of time-consuming experimental procedures for design and analysis.

Quasi-static Compressive Properties and Behavior of Single-cell Miura Origami Column Fabricated by 3D Printed PLA Material

2020 ◽  
Vol 3 (2) ◽  
pp. 66-73
Author(s):  
Farid Triawan ◽  
Geraldy Cahya Denatra ◽  
Djati Wibowo Djamari
Keyword(s):  
Single Cell ◽  
Peak Stress ◽  
Absorption Capacity ◽  
Compression Tests ◽  
Compressive Properties ◽  
Folding Pattern ◽  
Column Structure ◽  
Thin Walled ◽  
And Behavior ◽  
Initial Peak

The study of a thin-walled column structure has gained much attention due to its potential in many engineering applications, such as the crash box of a car. A thin-walled square column usually exhibits high initial peak force, which may become very dangerous to the driver or passenger. To address this issue, introducing some shape patterns, e.g., origami folding pattern, to the column may become a solution. The present work investigates the compressive properties and behavior of a square box column structure which adopts the Miura origami folding pattern. Several test pieces of single-cell Miura origami column with varying folding angle and layer height are fabricated by a 3D printer. The filament is made of Polylactic Acid (PLA), which is a brittle material. Then, compression tests are carried out to understand its compressive mechanical properties and behavior. The results show that introducing a Miura origami pattern to form a thin-walled square column can dramatically lower down the initial peak stress by 96.82% and, at the same time, increase its ductility, which eventually improves the energy absorption capacity by 61.68% despite the brittle fracture behavior.

scholarly journals Hybrid Seven-bar Press Mechanism

2018 ◽  
Vol 12 (3) ◽  
pp. 181-187
Author(s):  
M. Erkan Kütük ◽  
L. Canan Dülger
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Design Optimization ◽  
Hybrid System ◽  
Degrees Of Freedom ◽  
Dimensional Synthesis ◽  
Design Variables ◽  
Optimization Study ◽  
Metal Stamping

An optimization study with kinetostatic analysis is performed on hybrid seven-bar press mechanism. This study is based on previous studies performed on planar hybrid seven-bar linkage. Dimensional synthesis is performed, and optimum link lengths for the mechanism are found. Optimization study is performed by using genetic algorithm (GA). Genetic Algorithm Toolbox is used with Optimization Toolbox in MATLAB®. The design variables and the constraints are used during design optimization. The objective function is determined and eight precision points are used. A seven-bar linkage system with two degrees of freedom is chosen as an example. Metal stamping operation with a dwell is taken as the case study. Having completed optimization, the kinetostatic analysis is performed. All forces on the links and the crank torques are calculated on the hybrid system with the optimized link lengths

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

Compression tests on aluminum honeycomb and epoxy resin sandwich panels

2015 ◽  
Vol 4 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Shuliang Cheng ◽  
Xuya Zhao ◽  
Bo Xiao ◽  
Yajun Xin
Keyword(s):  
Epoxy Resin ◽  
Sandwich Panels ◽  
Compression Tests ◽  
Aluminum Honeycomb

Experimental and Numerical Investigation on Radial Stiffness of Origami-inspired Tubular Structures

2021 ◽  
pp. 1-30
Author(s):  
Weijun Shen ◽  
Yang Cao ◽  
Xuepeng Jiang ◽  
Zhan Zhang ◽  
Gül E. Okudan Kremer ◽  
...  
Keyword(s):  
Circular Tube ◽  
Weight Ratio ◽  
Design Parameters ◽  
Thin Wall ◽  
Tubular Structures ◽  
Compression Tests ◽  
Element Analysis ◽  
Radial Stiffness ◽  
Paper Folding ◽  
Engineering Problems

Abstract Origami structures, which were inspired by traditional paper folding arts, have been applied for engineering problems for the last two decades. Origami-based thin-wall tubes have been extensively investigated under axial loadings. However, less has been done with radial stiffness as one of the critical mechanical properties of a tubular structure working under lateral loadings. In this study, the radial stiffness of novel thin-wall tubular structures based on origami patterns have been studied with compression tests and finite element analysis (FEA) simulations. The results show that the radial stiffness of an origami-inspired tube can achieve about 27.1 times that of a circular tube with the same circumcircle diameter (100 mm), height (60 mm), and wall-thickness (2 mm). Yoshimura, Kresling, and modified Yoshimura patterns are selected as the basic frames, upon which the influences of different design parameters are tested and discussed. Given that the weight can vary due to different designs, the stiffness-to-weight ratio is also calculated. The origami-inspired tubular structures with superior stiffness performances are obtained and can be extended to crashworthy structures, functional structures, and stiffness enhancement with low structural weight.

Prediction of Sound Transmission Loss for Finite Sandwich Panels Based on a Test Procedure on Beam Elements

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Zhongchang Qian ◽  
Daoqing Chang ◽  
Bilong Liu ◽  
Ke Liu
Keyword(s):  
Sandwich Panel ◽  
Transmission Loss ◽  
Test Procedure ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Expansion Method ◽  
Bending Stiffness ◽  
Sound Transmission Loss ◽  
Modal Expansion ◽  
Beam Elements

An approach on the prediction of sound transmission loss for a finite sandwich panel with honeycomb core is described in the paper. The sandwich panel is treated as orthotropic and the apparent bending stiffness in two principal directions is estimated by means of simple tests on beam elements cut from the sandwich panel. Utilizing orthotropic panel theory, together with the obtained bending stiffness in two directions, the sound transmission loss of simply-supported sandwich panel is predicted by the modal expansion method. Simulation results indicated that dimension, orthotropy, and loss factor may play important roles on sound transmission loss of sandwich panel. The predicted transmission loss is compared with measured data and the agreement is reasonable. This approach may provide an efficient tool to predict the sound transmission loss of finite sandwich panels.

Experimental study on strength of cement stabilized clay

2005 ◽  
Vol 3 (2) ◽  
pp. 116-126 ◽  
Author(s):  
Woo‐Sik Kim ◽  
Nguyen Minh Tam ◽  
Du‐Hwoe Jung
Keyword(s):  
Compressive Strength ◽  
Soil Type ◽  
Unconfined Compressive Strength ◽  
Weight Ratio ◽  
Dry Weight ◽  
Strength Characteristics ◽  
Curing Time ◽  
Compression Tests ◽  
Soil Cement ◽  
Mixing Method

This paper describes the effect of factors on the strength characteristics of cement treated clay from laboratory tests performed on cement mixed clay specimens. It is considered that several factors such as soil type, sample preparing method, quantity of binder, curing time, etc. can have an effect on strength characteristics of cement stabilized clay. A series of unconfined compression tests have been performed on samples prepared with different conditions. The results indicated that soil type, mixing method, curing time, dry weight ratio of cement to clay (Aw), and water‐clay to cement (wc/c) ratio were main factors which can have an influence on unconfined compressive strength, modulus of elasticity, and failure strain of cement stabilized clay. Unconfined compressive strength of soil‐cement samples prepared from dry mixing method was higher than those prepared from wet mixing method.

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