Numerical Simulation of Linear Frequency Modulation Infrared Thermal Wave Detection for GFRP/Nomex Honeycomb Sandwich Structure

2020 ◽  
Author(s):  
Tang Qingju ◽  
Fan Weiming
Keyword(s):  
Numerical Simulation ◽  
Frequency Modulation ◽  
Thermal Wave ◽  
Sandwich Structure ◽  
Linear Frequency Modulation ◽  
Linear Frequency ◽  
Wave Detection ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Honeycomb Sandwich Structure

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.

scholarly journals Micro Fracture Behavior of Composite Honeycomb Sandwich Structure

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 135
Author(s):  
Guangjian Bi ◽  
Jianping Yin ◽  
Zhijun Wang ◽  
Zijian Jia
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Fracture Energy ◽  
Energy Absorption ◽  
Sandwich Structure ◽  
Great Influence ◽  
Energy Curve ◽  
Energy Calculation ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Structure

To study the influence of structure size and composite forms on the mechanical properties of the composite double honeycomb sandwich structure, a composite double honeycomb sandwich structure was initially designed. The dynamic response of a composite double-layer honeycomb sandwich structure under high-speed impact was studied through theoretical analysis and numerical simulation. Ls-dyna software was used to simulate the initially designed composite structure. According to the numerical simulation results and the proposed method for calculating the fracture energy of the composite double honeycomb sandwich structure, the effects of different composite forms on the mechanical properties were analyzed. The results show that the proposed fracture energy calculation method can effectively describe the variation trend of the honeycomb structure and the micro-element fracture situation in the valid time. The fracture energy curve has a high sensitivity to cell density and material, and the strength of the top core has a great influence on the overall energy absorption. Compared with the traditional honeycomb protection structure, the energy absorption of the initially designed composite honeycomb sandwich structure was improved effectively.

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.

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.

scholarly journals Thermal barrier coating debonding defects detection based on infrared thermal wave testing technology under linear frequency modulation heat exitation

2019 ◽  
Vol 23 (3 Part A) ◽  
pp. 1607-1613
Author(s):  
Yuanlin Liu ◽  
Guojin Zhao ◽  
Yongzhi Du ◽  
Yang Zhang
Keyword(s):  
Light Source ◽  
Frequency Modulation ◽  
Thermal Wave ◽  
Signal To Noise Ratio ◽  
Linear Frequency Modulation ◽  
Thermal Barrier ◽  
Signal To Noise ◽  
Linear Frequency ◽  
Barrier Coating ◽  
Testing Technology

Thermal barrier coating debonding defects detection based on infrared thermal wave testing technology under linear frequency modulation heat excitation was studied. The principle the infrared thermal wave testing technology under linear frequency modulation was presented. The effects of different light source power and Chirp modulation frequency on signal-to-noise ratio were compared and analyzed. The results show that, defects can be more easily detected with the bigger power of light source, and the signal-to-noise ratio can be increased by using lower initial and termination frequencies.

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