Investigation of sandwich composite failure under three-point bending: Simulation and experimental validation

2018 ◽  
Vol 22 (6) ◽  
pp. 1838-1858 ◽  
Author(s):  
Sudharshan Anandan ◽  
Gurjot Dhaliwal ◽  
Shouvik Ganguly ◽  
K Chandrashekhara

A sandwich structure consists of a two thin and strong facesheets, bonded to a thick lightweight core material. The mechanical response of a sandwich structure depends on the properties of its constituents. A numerical model and experimental validation of the three-point bending test of sandwich composites are presented in this study. The core material is aluminum honeycomb. The facesheets are made of IM7/Cycom5320-1, which is a carbon fiber/epoxy prepreg system. A comprehensive model of the failure under flexural loading was developed. Facesheet failure was modeled using Hashin’s failure criteria. A detailed meso-scale model of the honeycomb core was included in the model. The experiments indicated that failure initiation was due to local buckling in the honeycomb core. Failure propagation was in the form of core failure, facesheet compressive failure, and interlaminar failure. The developed meso-scale model was able to accurately simulate failure initiation and propagation in the composite sandwich structure. The effect of elevated temperature on the three-point bending behavior was studied numerically as well as experimentally. An increase in test temperature to 100°C resulted in a drop of 9.2% in flexural strength, which was also predicted by the numerical model.

Author(s):  
M.R. Ashok ◽  
M. Manojkumar ◽  
P.V. Inbanaathan ◽  
R. Shanmuga Prakash

This paper details the fabrication and flexural testing of sandwich structure with Aluminium honeycomb core with Aluminium face skins. The material for the face skin is aluminium 1100 and for the core is Aluminium AA8011. The cell size obtained by fabrication is 7mm. The specimen is prepared and tested as per the ASTM standard C393/C393M-11 on a three-point bending test to obtain the ultimate core shear strength and the face skin strength. Finite element analysis is also carried out to validate the experimental test.


2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek

This research paper deals with an investigation of the influence of honeycomb core compression on the mechanical properties of sandwich structures. These structures consist of prepreg facing layers and two different material types of honeycomb and are produced by modified compression molding called Crush-Core technology. Produced structures are mechanically tested in three-point bending test and subjected to low-velocity impact and Charpy impact test.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2325 ◽  
Author(s):  
Jingxin Hao ◽  
Xinfeng Wu ◽  
Gloria Oporto ◽  
Jingxin Wang ◽  
Gregory Dahle ◽  
...  

A new type of Taiji honeycomb structure bonded outside with wood-based laminates was characterized from a mechanical standpoint. Both theoretical and experimental methods were employed to analyze comprehensively the deformation behavior and failure mechanism under a three-point bending test. The analytical analysis reveals that a Taiji honeycomb has 3.5 times higher strength in compression and 3.44 times higher strength in shear compared with a traditional hexagonal honeycomb. Considering the strength-weight issue, the novel structure also displays an increase in compression strength of 1.75 times and shear strength of 1.72 times. Under a three-point bending test, indentation and core shear failure played the dominant role for the total failure of a wooden sandwich with Taiji honeycomb core. Typical face yield was not observed due to limited thickness-span ratio of specimens. Large spans weaken the loading level due to the contribution of global bending stress in the compressive skin to indentation failure. A set of analytical equations between mechanical properties and key structure parameters were developed to accurately predict the threshold stresses corresponding to the onset of those deformation events, which offer critical new knowledge for the rational structure design of wooden sandwich composites.


2010 ◽  
Vol 160-162 ◽  
pp. 855-859 ◽  
Author(s):  
Li Qing Meng ◽  
Yan Wu ◽  
Shi Zhe Chen ◽  
Xue Feng Shu

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.


2014 ◽  
Vol 84 (18) ◽  
pp. 1915-1930 ◽  
Author(s):  
Liwei Wu ◽  
Bohong Gu

This paper reports the computational results of the bending fatigue behaviors of four-step three-dimensional rectangular braided composite materials from a meso-scale approach. A full-size meso-scale model of a four-step three-dimensional braided composite was established to numerically analyze the deformation and damage under cyclic bending loading. The stress distribution, energy absorption, hysteresis loop features and damage morphologies were obtained to explain the structural effects on the deformation and damage of the three-dimensional braided composite material subjected to three-point bending cyclic loading. The influences of the microstructure on the fatigue behaviors have been discussed for designing the three-dimensional braided composite material with high fatigue damage tolerance.


2012 ◽  
Vol 490-495 ◽  
pp. 2743-2747 ◽  
Author(s):  
Zong Hong Xie ◽  
Wei Zhao ◽  
Lei Li ◽  
Peng Zhang

This paper focuses on the research and development of the “Multi-functional Composite Embedded Smart-Skin Antenna (MECSSA) Structure” with load-bearing, shape maintaining and communication capabilities. MECSSA structure consists of top and bottom composite thin facesheet, honeycomb core, 4 by 8 micro-strip antenna arrays located among honeycomb core and some adhesive. Simulation and experiment methods were used to study the performance of MECSSA structure. Through the study we found that adhesive is the significant factor of affecting the electrical performance of MECSSA structure, especially for radio frequency (RF) and it must take into account in the research. There may be two ways to avoid the influence of adhesive: compensation and separation. Three point bending test indicated that the strength of MECSSA structure satisfies design requirements.


2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Xinyun Zhang ◽  
Kangwen Sun ◽  
Dongdong Xu ◽  
Shijun Guo

A semirigid solar array is an efficient energy system on the surface of stratospheric airships for utilizing the solar energy, which we believe that it has succeeded in providing some impressive results for conceptual design. This paper developed a lightweight photovoltaic composite structure (LPCS) according to the characteristics of the stratospheric airship capsule. In order to improve the flexibility of the solar cell, we studied the mechanical properties in the different thicknesses of the honeycomb core for LPCS by FEM software and three-point bending test, and we also launched experiments to measure the temperature difference between upper and lower surfaces of the LPCS test samples under different solar radiation flux conditions. The experimental data were examined to evaluate the mechanical properties and thermal insulation performances of LPCS. Considering the quality of the whole structure, the paper finally comes up with the conclusion of the optimal thickness of the honeycomb core with further detailed descriptions.


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