scholarly journals Experimental Analysis of Perimeter Shear Strength of Composite Sandwich Structures

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 12
Author(s):  
Łukasz Święch ◽  
Radosław Kołodziejczyk ◽  
Natalia Stącel
Keyword(s):  
Experimental Analysis ◽  
Sandwich Structures ◽  
Maximum Load ◽  
Core Material ◽  
Foam Core ◽  
Honeycomb Core ◽  
Loading Test ◽  
Composite Sandwich ◽  
Destruction Mechanism ◽  
Static Loading Test

The work concerns the experimental analysis of the process of destruction of sandwich structures as a result of circumferential shearing. The aim of the research was to determine the differences that occur in the destruction mechanism of such structures depending on the thickness and material of the core used. Specimens with a Rohacell foam core and a honeycomb core were made for the purposes of the research. The specimen destruction process was carried out in a static loading test with the use of a system introducing circumferential shear stress. The analysis of the tests results was made based on the load-displacement curves, the maximum load, and the energy absorbed by individual specimens. The tests indicated significant differences in the destruction mechanism of specimens with varied core material. The specimen with the honeycomb core was characterized by greater stiffness, which caused the damage to occur locally in the area subjected to the pressure of the punch. In specimens with the foam core, due to the lower stiffness of that core, the skins of the structure were bent, which additionally transfers compressive and tensile loads. This led to a higher maximum force that the specimens obtained at the time of destruction and greater energy absorption.

Evaluation of skin-core adhesion bond of out-of-autoclave honeycomb sandwich structures

2012 ◽  
Vol 31 (5) ◽  
pp. 331-339 ◽  
Author(s):  
R.R. Butukuri ◽  
V.P. Bheemreddy ◽  
K. Chandrashekhara ◽  
T.R. Berkel ◽  
K. Rupel
Keyword(s):  
Cell Size ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Core Material ◽  
Honeycomb Core ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Film Adhesive ◽  
Adhesive Thickness ◽  
Out Of Autoclave

Composite sandwich structures offer several advantages over conventional structural materials such as lightweight, high bending and torsional stiffness, superior thermal insulation and excellent acoustic damping. One failure mechanism in a composite sandwich structure is the debonding of the composite facesheets from the core structure. A well-formed adhesive fillet at the interface of the honeycomb core cell walls and the laminate is a significant factor in preventing bond failure. In the present work, honeycomb composite sandwich panels are manufactured using a low-cost vacuum-bag-pressure-only out-of-autoclave manufacturing process. CYCOM®5320 out-of autoclave prepreg is used for the facesheet laminates and FM® 300-2U film adhesive is used for the facesheet-to-core bond. The manufactured composite sandwich panels are of aerospace quality with a facesheet laminate void content of around 1%. In this study, adhesive fillet formation and adhesive mechanical strength are evaluated as a function of several different sandwich construction design variables. Both aluminum and aramid Nomex® honeycomb core materials are considered to study the effect of core cell size and core material. The effect of film adhesive thickness is studied. A process for reticulation of the adhesive is applied and studied. A quantitative investigation of the adhesive fillet geometry is carried out for all the panels. Manufactured panels are evaluated for flatwise tensile strength in accordance with test method ASTM C297. Optimized combinations of core material, core density, cell size and adhesive thickness are identified. Results show that the reticulation process improves fillet formation and increases flatwise tensile properties.

Comparing the Impact Response of 3D Fiber Reinforced Foam Core with Monolithic Foam Core in Composite Sandwich Structures

2021 ◽  
Author(s):  
Michael J. Wu ◽  
Steffen Tai ◽  
Jacob Rome ◽  
Vinay K. Goyal ◽  
Zachary T. Kier ◽  
...  
Keyword(s):  
Sandwich Structures ◽  
Impact Response ◽  
Foam Core ◽  
Fiber Reinforced ◽  
Composite Sandwich ◽  
Composite Sandwich Structures ◽  
The Impact

Low Velocity Impact Response of Composite/Sandwich Structures

2016 ◽  
Vol 725 ◽  
pp. 127-131 ◽  
Author(s):  
Kumar V. Akshaj ◽  
P. Surya ◽  
M.K. Pandit
Keyword(s):  
Sandwich Structures ◽  
Weight Ratio ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Design Parameters ◽  
Low Velocity ◽  
Velocity Impact ◽  
Composite Sandwich ◽  
Set Up

Dent resistance of structures is one of the important design parameters to consider in automotive, aerospace, packaging and transportation of fragile goods, civil engineering and marine industries. It is important to study the dynamic impact response of various combinations of skin and core materials which can provide desired fracture toughness and highest strength to weight ratio for such applications. This paper discusses the low velocity impact response of sandwich structures having unique combination of mild steel as skin material bonded to thermoplastics/PU foam as core material. HDPE, LDPE and polypropylene were the choice of thermoplastics and an optimum combination of materials for the sandwich structure was evaluated using drop-weight experimental set up. It is observed that LDPE is the best choice of core material for the sandwich structures considered.

Experimental investigations on the sandwich composite beams and panels with elastomeric foam core

2017 ◽  
Vol 21 (3) ◽  
pp. 865-894 ◽  
Author(s):  
AR Nazari ◽  
H Hosseini-Toudeshky ◽  
MZ Kabir
Keyword(s):  
Carrying Capacity ◽  
Sandwich Structures ◽  
Failure Mechanisms ◽  
Composite Beams ◽  
Core Material ◽  
Foam Core ◽  
Sandwich Beams ◽  
Load Carrying Capacity ◽  
The Core ◽  
Load Carrying

In this paper, the load-carrying capacity and failure mechanisms of sandwich beams and panels with elastomeric foam core and composite laminate face sheets are investigated. For this purpose, the flexural behavior of laminated composite beams and panels (applied as face sheets) is firstly investigated under three-point bending and central concentrated loads, respectively. Then, the same examination is conducted for the sandwich beams and panels, in which the proposed elastomeric foam is utilized as the core material. It is shown that the failure mechanisms which are associated to the core in the sandwich structures with crushable foams are not considered in the examined sandwich structures. The collapse of the sandwich specimens, examined here, is observed due to the failure of the skins in some steps. By multi-step collapse of these specimens via separately failure of the top and bottom skins, a considerable amount of energy is absorbed between these steps. Due to non-brittle behavior of the core material under loading, a large compression resistance is observed after failure of the top skin which led to the recovery of the load-carrying capacity in the sandwich beams. A similar behavior for the sandwich panels led to the increase of the ultimate strength after appearance of the failure lines on the top skin. The general outcomes of this investigation promise a good influence for the application of elastomeric foam as core material for sandwich structures.

Fatigue of Foam and Honeycomb Core Composite Sandwich Structures: A Tutorial

2006 ◽  
Vol 8 (4) ◽  
pp. 263-319 ◽  
Author(s):  
Nitin Sharma ◽  
Ronald F. Gibson ◽  
Emmanuel O. Ayorinde
Keyword(s):  
Sandwich Structures ◽  
Honeycomb Core ◽  
Composite Sandwich ◽  
Composite Sandwich Structures

Quasi-Static Failure Analysis of Honeycomb Sandwich Beam with Composite Facesheets

2010 ◽  
Vol 160-162 ◽  
pp. 855-859 ◽  
Author(s):  
Li Qing Meng ◽  
Yan Wu ◽  
Shi Zhe Chen ◽  
Xue Feng Shu
Keyword(s):  
Sandwich Beam ◽  
Indentation Test ◽  
Core Material ◽  
Honeycomb Core ◽  
Three Point Bending ◽  
Composite Sandwich ◽  
Sandwich Construction ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Static Failure

Sandwich construction consists of two thin composite or metal facesheets separated by a core material. Despite extensive researches on the sandwich constructions, their mechanical properties and failure behaviours are still not fully understand. The objective of the paper is to use a experimental and theoretical predicting failure mode for sandwich beam consisting of GFRP facesheets and Nomex honeycomb core. Two kinds of composite sandwich beams are observed in quasi-static three-point bending and indentation test.

scholarly journals Mechanical Performance of Honeycomb Sandwich Structures Using Three-Point Bend Test

2019 ◽  
Vol 9 (2) ◽  
pp. 3955-3958
Author(s):  
T. Subhani
Keyword(s):  
Mechanical Performance ◽  
Sandwich Structures ◽  
Bend Test ◽  
Core Material ◽  
Honeycomb Core ◽  
Adhesive Film ◽  
Honeycomb Sandwich ◽  
Point Bend Test ◽  
Three Point Bend Test ◽  
Point Bend

In this study, honeycomb sandwich structures were prepared and tested. Facesheets of sandwich structures were manufactured by carbon fiber epoxy matrix composites while Nomex® honeycomb was used as core material. An epoxy-based adhesive film was used to bond the composite facesheets with honeycomb core. Four different curing temperatures ranging from 100oC to 130oC were applied with curing times of 2h and 3h. Three-point bend test was performed to investigate the mechanical performance of honeycomb sandwich structures and thus optimize the curing parameters. It was revealed that the combination of a temperature of 110oC along with a curing time of 2h offered the optimum mechanical performance together with low damage in honeycomb core and facesheets.

Load-Carrying Characteristics of Foam Core and Joint Geometry in Sandwich Structures

2020 ◽  
Author(s):  
Jonas W. Ringsberg
Keyword(s):  
Structural Integrity ◽  
Side Wall ◽  
Core Material ◽  
Fe Model ◽  
Foam Core ◽  
Stress Concentrations ◽  
Production Time ◽  
Composite Sandwich ◽  
The Core ◽  
Load Carrying

Abstract Composite sandwich ships have laminated joints that contribute to a significant part of the ship’s weight. Their construction requires an extensive number of man-hours. There is great potential for weight and production-time-reduction through alternative joint designs. According to class rules, one is not allowed to benefit from the load-carrying capability of the core, i.e. the strength characteristics of the core shall be disregarded and geometry at the joint location is disregarded as well. The objective of the current investigation was to investigate the possibility of constructing a joint where the load-carrying capability of the foam core is accounted for, leading to a reduction in weight and production time. One specific joint in a 23 m composite sandwich catamaran was selected for study — a side wall-wet deck T-joint. This joint is considered to be crucial for the structural integrity of the current vessel. A global finite element (FE) model of the catamaran was designed and analysed in ANSYS. The loads and boundary conditions were applied to the global model according to DNV GL’s HSLC rules. Two local FE models of the joints (2D and 3D) were utilized for a parametric analysis with respect to structure response (stress concentrations and compliance with failure and fracture criteria). Finally, the results and conclusions from the study show the possibilities and advantages of incorporating the foam core material as a load-carrying member in joint design without compromising safety.

NUMERICAL MODEL OF TUBULAR COMPOSITE SANDWICH STRUCTURES UNDER LOW-VELOCITY IMPACT

2021 ◽  
Author(s):  
CHAO ZHANG ◽  
ISAIAH KAISER ◽  
K. T. TAN
Keyword(s):  
Sandwich Structures ◽  
Matrix Cracking ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Low Velocity ◽  
Damage Mechanisms ◽  
Velocity Impact ◽  
Composite Sandwich ◽  
Composite Sandwich Structures

This study aims to investigate the dynamic impact response of tubular composite structures with honeycomb sandwich core under transverse low-velocity impact (LVI) test. We establish a finite element analysis (FEA) model of composite sandwich structures. Simulation results are compared with experimental results to verify the correctness of the model and analysis method. This model can accurately predict the impact response and damage mechanisms of a composite sandwich structure, as validated by experimental testing, specifically capturing major failure modes. LVI experiments are conducted utilizing cylindrical impact striker to enact both point and line impact. Damage mechanisms, such as matrix cracking, delamination, and fiber breakage/rupture, occur in the facesheet, as well as honeycomb crushing and breakage in the core. The combination of experimental and numerical results illustrates the effects of facesheet thickness and core thickness on failure mechanisms. A three-dimensional model can also be used to clearly visualize the effect of different core material properties on the failure mechanism and dynamic response during an impact event.

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