Out-of-plane shear property analysis of Nomex honeycomb sandwich structure

2020 ◽  
pp. 073168442094328 ◽  
Author(s):  
Yue Liu ◽  
Wei Liu ◽  
Weicheng Gao
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Sandwich Structure ◽  
Honeycomb Core ◽  
Plane Shear ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Nomex Honeycomb ◽  
Analytical Expressions ◽  
Honeycomb Sandwich Structure

Honeycomb sandwich structure finds immense applications in aerospace manufacturing and other similar fields. The Nomex honeycomb sandwich structural material exhibits a complex structure and boundary conditions, making it difficult to obtain exact solutions for the equivalent out-of-plane shear modulus and shear strength of the Nomex honeycomb using current analytical methods. To this end, based on the energy method, the Kelsey model is simplified in this paper. Then, distribution of the shear forces in the longitudinal and transverse directions of the Nomex honeycomb core is analysed using the simplified model. Considering the effect of the wall thickness of the honeycomb core on the ultimate strength, the analytical expressions of the out-of-plane shear modulus and shear strength of the Nomex honeycomb are proposed. The shear properties and failure process of the Nomex honeycomb in two directions are then analysed experimentally. The accuracy of the analytical expressions of the equivalent shear modulus and shear strength is verified experimentally. The equivalent out-of-plane shear modulus and shear strength of the honeycomb was demonstrated to be effectively predicted by the analytical approach.

Experimental Study on the Mechanical Properties of Two Sandwich Structure Composite Materials

2013 ◽  
Vol 561 ◽  
pp. 466-471
Author(s):  
Chuan Sheng Wang ◽  
Qing Kun Liu
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Composite Materials ◽  
Sandwich Structure ◽  
National Standards ◽  
Honeycomb Sandwich ◽  
Pros And Cons ◽  
Nomex Honeycomb ◽  
Honeycomb Sandwich Structure

According to the relevant national standards, this paper produced Corecell ™ G foam sandwich structure and Nomex honeycomb sandwich structure composite materials specimens. These two materials were carried out tensile, compression, bending and shear experiment. Analyzing and comparing the pros and cons of the two materials in the mechanical properties of tensile strength, compressive strength, shear strength, flexural strength.

Detection of Unbonds in Honeycomb Sandwich Structure Using Lock-In Thermography

2010 ◽  
Vol 97-101 ◽  
pp. 4363-4366
Author(s):  
Hui Liu ◽  
Jun Yan Liu ◽  
Yang Wang ◽  
Hui Juan Li
Keyword(s):  
Sandwich Structure ◽  
Sandwich Structures ◽  
Modulation Frequency ◽  
Influencing Factor ◽  
Face Sheet ◽  
Honeycomb Core ◽  
Honeycomb Sandwich ◽  
Testing Technology ◽  
Lock In ◽  
Honeycomb Sandwich Structure

Lock-in thermography (LT), that is active infrared testing technology, mainly includes optical lock-in thermography (OLT) and ultrasound lock-in thermography (ULT). LT can be used to detect unbonds between honeycomb core and face sheet of sandwich structures. However, modulation frequency is an important influencing factor. In this paper, the principles of LT are represented, in experimental detections of simulated unbonds in honeycomb sandwich structures with Al-face sheet and CFRP-face sheet using OLT and ULT, detectability of OLT and ULT is compared and analyzed, effect of modulation frequency is researched and the optimal frequencies are obtained.

Ballistic performance of honeycomb sandwich structures reinforced by functionally graded face plates

2017 ◽  
Vol 21 (1) ◽  
pp. 211-229 ◽  
Author(s):  
Recep Gunes ◽  
Kemal Arslan ◽  
M Kemal Apalak ◽  
JN Reddy
Keyword(s):  
Sandwich Structure ◽  
Sandwich Structures ◽  
Threshold Energy ◽  
Functionally Graded ◽  
Honeycomb Core ◽  
Ballistic Performance ◽  
Damage Area ◽  
Honeycomb Sandwich ◽  
Aluminum Honeycomb ◽  
Honeycomb Sandwich Structure

This study investigates damage mechanisms and deformation of honeycomb sandwich structures reinforced by functionally graded face plates under ballistic impact. The honeycomb sandwich structure consists of two identical functionally graded face sheets, having different material compositions through the thickness, and an aluminum honeycomb core. The functionally graded face sheets consist of ceramic (SiC) and aluminum (Al 6061) phases. The through-thickness mechanical properties of face sheets are assumed to vary according to a power-law. The locally effective material properties are evaluated using the Mori–Tanaka scheme. The effect of material composition of functionally graded face sheets on the ballistic performance of honeycomb sandwich structures was investigated using the finite element method and the penetration and perforation threshold energy values on ballistic performance and ballistic limit of the sandwich structures are determined. The contribution of the honeycomb core on the ballistic performance of the sandwich structure was evaluated by comparing with spaced plates (without honeycomb core) in terms of the residual velocity, kinetic energy, and damage area.

scholarly journals Defect detection of GFRP/Nomex honeycomb sandwich structure by linear frequency modulation infrared thermal imaging

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4611-4619
Author(s):  
Qing-Ju Tang ◽  
Wei-Ming Fan ◽  
Juan Ji ◽  
Ya-Fei Song
Keyword(s):  
Principal Component Analysis ◽  
Sandwich Structure ◽  
Signal To Noise Ratio ◽  
Principal Component ◽  
Component Analysis ◽  
Signal To Noise ◽  
Honeycomb Sandwich ◽  
Water Accumulation ◽  
Nomex Honeycomb ◽  
Honeycomb Sandwich Structure

Honeycomb sandwich material is a new material widely used in many fields, but it is easy to produce defects such as delamination and ponding in the process of manufacturing and service. First, a honeycomb sandwich sample containing delamination defects and water accumulation was built. Then, a linear frequency modulated driving halogen lamp is used as the excitation source. Finally, the surface thermal image sequence of the test sample is acquired by infrared thermal imager. Image sequences are processed by inter-frame difference-multi-frame cumulative average method, principal component analysis, Fourier transform method, and logarithmic polynomial fitting method, respectively. Define and calculate the signal-to-noise ratio of the heat map processed by each algorithm. Compared with the other three algorithms, the principal component analysis method processed the image with the highest signal-to-noise ratio and high contrast. This algorithm achieves effective identification of delamination defects and water accumulation in GFRP/Nomex honeycomb sandwich structure.

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