The Through-Thickness Compressive Strength of a Composite Sandwich Panel With a Hierarchical Square Honeycomb Sandwich Core

2009 ◽  
Vol 76 (6) ◽  
Author(s):  
F. Côté ◽  
B. P. Russell ◽  
V. S. Deshpande ◽  
N. A. Fleck
Keyword(s):  
Finite Element ◽  
Compressive Strength ◽  
Sandwich Panel ◽  
Analytical Models ◽  
Composite Sandwich ◽  
Hierarchical Topology ◽  
Collapse Mechanisms ◽  
Strength Based ◽  
Out Of Plane ◽  
Plane Compression

Sandwich panels with aluminum alloy face sheets and a hierarchical composite square honeycomb core have been manufactured and tested in out-of-plane compression. The prismatic direction of the square honeycomb is aligned with the normal of the overall sandwich panel. The cell walls of the honeycomb comprise sandwich plates made from glass fiber/epoxy composite faces and a polymethacrylimide foam core. Analytical models are presented for the compressive strength based on three possible collapse mechanisms: elastic buckling of the sandwich walls of the honeycomb, elastic wrinkling, and plastic microbuckling of the faces of the honeycomb. Finite element calculations confirm the validity of the analytical expressions for the perfect structure, but in order for the finite element simulations to achieve close agreement with the measured strengths it is necessary to include geometric imperfections in the simulations. Comparison of the compressive strength of the hierarchical honeycombs with that of monolithic composite cores shows a substantial increase in performance by using the hierarchical topology.

The Damage Tolerance of a Sandwich Panel Containing a Cracked Honeycomb Core

2009 ◽  
Vol 76 (6) ◽  
Author(s):  
I. Quintana Alonso ◽  
N. A. Fleck
Keyword(s):  
Finite Element ◽  
Sandwich Panel ◽  
Finite Element Simulations ◽  
Analytical Models ◽  
Tensile Fracture ◽  
Linear Elastic ◽  
Statistical Variation ◽  
Wall Strength ◽  
Elastic Fracture ◽  
Weibull Theory

The tensile fracture strength of a sandwich panel, with a center-cracked core made from an elastic-brittle diamond-celled honeycomb, is explored by analytical models and finite element simulations. The crack is on the midplane of the core and loading is normal to the faces of the sandwich panel. Both the analytical models and finite element simulations indicate that linear elastic fracture mechanics applies when a K-field exists on a scale larger than the cell size. However, there is a regime of geometries for which no K-field exists; in this regime, the stress concentration at the crack tip is negligible and the net strength of the cracked specimen is comparable to the unnotched strength. A fracture map is developed for the sandwich panel with axes given by the sandwich geometry. The effect of a statistical variation in the cell-wall strength is explored using Weibull theory, and the consequences of a stochastic strength upon the fracture map are outlined.

Six-Dimensional Compliance Analysis and Validation of Orthoplanar Springs

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Chen Qiu ◽  
Peng Qi ◽  
Hongbin Liu ◽  
Kaspar Althoefer ◽  
Jian S. Dai
Keyword(s):  
Finite Element ◽  
Parallel Mechanism ◽  
Fem Simulation ◽  
Analytical Models ◽  
Compliance Matrix ◽  
Out Of Plane ◽  
Continuum Manipulator ◽  
First Time ◽  
Good Agreement

This paper for the first time investigates the six-dimensional compliance characteristics of orthoplanar springs using a compliance-matrix based approach, and validates them with both finite element (FEM) simulation and experiments. The compliance matrix is developed by treating an orthoplanar spring as a parallel mechanism and is revealed to be diagonal. As a consequence, corresponding diagonal compliance elements are evaluated and analyzed in forms of their ratios, revealing that an orthoplanar spring not only has a large linear out-of-plane compliance but also has a large rotational bending compliance. Both FEM simulation and experiments were then conducted to validate the developed compliance matrix. In the FEM simulation, a total number of 30 types of planar-spring models were examined, followed by experiments that examined the typical side-type and radial-type planar springs, presenting a good agreement between the experiment results and analytical models. Further a planar-spring based continuum manipulator was developed to demonstrate the large-bending capability of its planar-spring modules.

Study on the Residual Compressive Strength of a Composite Sandwich Panel with Foam Core after Low Velocity Impact

2012 ◽  
Vol 430-432 ◽  
pp. 484-487 ◽  
Author(s):  
Zong Hong Xie ◽  
Jiang Tian ◽  
Jian Zhao ◽  
Wei Li
Keyword(s):  
Compressive Strength ◽  
Failure Criterion ◽  
Sandwich Panel ◽  
Low Velocity Impact ◽  
Foam Core ◽  
Low Velocity ◽  
Velocity Impact ◽  
Residual Compressive Strength ◽  
Composite Sandwich ◽  
The Impact

The residual compressive strength of a foam core sandwich panel after low-velocity impact was studied by using experimental and analytical methods. The test specimens were compressed uniaxially after they were subjected to a low-velocity-impact. From the observation in the test, one can conclude that the subsequent core crushing around the impact region is the major failure mode in the sandwich structure. A failure criterion named Damage Propagation Criterion was proposed to predict the residual compressive load bearing capability of the low-velocity impacted composite sandwich panel. The characteristic value used in this failure criterion can be calculated by an analytical model developed or by conducting the Sandwich Compression after Impact test.

Finite Element Study on the Influence of Shear Key Diameter on the Shear Performance of Composite Sandwich Panel with PU Foam Core

2013 ◽  
Vol 376 ◽  
pp. 103-107
Author(s):  
A. Mostafa ◽  
K. Shankar
Keyword(s):  
Finite Element ◽  
Failure Mode ◽  
Sandwich Panel ◽  
Mechanical Response ◽  
Shear Loading ◽  
Foam Core ◽  
Element Analysis ◽  
Composite Sandwich ◽  
The Core ◽  
Pu Foam

The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.

Confined masonry walls subjected to combined axial loads and out-of-plane uniform pressures

2012 ◽  
Vol 39 (4) ◽  
pp. 439-447 ◽  
Author(s):  
Jorge Varela-Rivera ◽  
Manuel Polanco-May ◽  
Luis Fernandez-Baqueiro ◽  
Eric I. Moreno
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Axial Load ◽  
Analytical Models ◽  
Maximum Pressure ◽  
Masonry Walls ◽  
The Finite Element Method ◽  
Axial Loads ◽  
Confined Masonry ◽  
Out Of Plane

This paper presents the results of a study on the behavior of three full-scale confined masonry walls subjected to combined axial loads and out-of-plane uniform pressures. The variable studied was the wall axial load. Analytical models were developed to predict out-of-plane cracking and maximum pressures. The former was predicted using the finite element method and the latter using the spring-strut method. This last method was modified to include the effect of the wall axial load. Experimental cracking and maximum pressures were compared with those obtained from analytical models. Based on the experimental results, it was concluded that as the axial load increases, the out-of-plane maximum pressure also increases. However, this latter value is limited by crushing of the masonry. By comparing experimental and analytical results, it was concluded that the out-of-plane cracking and maximum pressures are in general well predicted by the analytical models developed in this work.

Numerical Analysis of Quasi-Static Out-of-Plane Compression of Miura-Ori Patterned Sheets

2019 ◽  
Author(s):  
Xinmei Xiang ◽  
Guoxing Lu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cell Wall ◽  
Parametric Analysis ◽  
Reasonable Agreement ◽  
Dihedral Angles ◽  
Element Analysis ◽  
Out Of Plane ◽  
Plane Compression ◽  
Simulation Results

Abstract In this paper, quasi-static out-of-plane compression behaviors of Miura-ori patterned sheets were investigated numerically by using finite element analysis (FEA). The simulation results show a reasonable agreement with the experimental results. In addition, the parametric analysis of the Miura-ori patterned sheets with different cell wall thicknesses, side lengths, dihedral angles and sector angles were carried out using FEA method. The influences of different parameters on the peak force and mean force were determined.

Out-of-plane compression of a novel hybrid corrugated core sandwich panel

2021 ◽  
pp. 114222
Author(s):  
Shanyouming Sun ◽  
Dan Liu ◽  
Yinglong Sheng ◽  
Shangsheng Feng ◽  
Hongbin Zhu ◽  
...  
Keyword(s):  
Sandwich Panel ◽  
Out Of Plane ◽  
Plane Compression
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