Thermal and Thermomechanical Performances of Pyramidal Core Sandwich Panels Under Aerodynamic Heating

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Gongnan Xie ◽  
Ruiping Zhang ◽  
Oronzio Manca
Keyword(s):  
Sandwich Panel ◽  
Thermal Protection ◽  
Sandwich Panels ◽  
Core Structure ◽  
Heat Transfer Analysis ◽  
Aerodynamic Heating ◽  
Load Bearing ◽  
Sequential Coupling ◽  
Protection Property ◽  
Integrated Thermal Protection System

According to the particular aerodynamic heating loads which hypersonic aerospace aircrafts suffered from in-service environment, a lightweight integrated thermal protection system (ITPS) named pyramidal core sandwich panel is designed. This is considered not only as an insulation structure but also a load-bearing structure. Compared to traditional thermal protection systems (TPSs), the sandwich panel has simultaneous lightweight, load-bearing, and excellent thermal protection property. The finite-element heat transfer analysis for the pyramidal core sandwich structure is performed, and the distributions of temperature in the structure are presented. Then sequential coupling method is adopted to analyze the thermomechanical performance of the structure and presentations of field of stress and displacement under aerodynamic and thermal load are provided. A comparison between corrugated-core sandwich panels and pyramidal core sandwich panels from the perspectives of heat insulation, strength, and mass is carried out. The results indicate that the particular performance of pyramidal-core structure is superior to that of corrugated-core structure.

scholarly journals Optimization and Re-Design of Integrated Thermal Protection Systems Considering Thermo-Mechanical Performance

2021 ◽  
Vol 11 (15) ◽  
pp. 6916
Author(s):  
Qiuyi Xu ◽  
Shu Li ◽  
Yang Meng
Keyword(s):  
Thermal Insulation ◽  
Mechanical Performance ◽  
Thermal Protection ◽  
Elastic Strain Energy ◽  
Topological Optimization ◽  
Bottom Surface ◽  
Optimized Design ◽  
Buckling Mode ◽  
Load Bearing ◽  
Integrated Thermal Protection System

Integrated thermal protection system (ITPS) is regarded as one of the most promising thermal protection concepts with both thermal insulation and load-bearing capacities. However, the traditional layout of webs could inevitably lead to thermal short effects and high risk of buckling failure of the ITPS. A topological optimization method for the unit cell of the ITPS was established to minimize the equivalent thermal conductivity and elastic strain energy with the constraint of maintaining structural efficiency. The ITPS was re-designed consulting the optimized cell configuration. In order to control the buckling-mode shape and the associated buckling load of the ITPS, the new design was further optimized, subjected to the total weight of the initial design. Detailed finite element models were established to validate the structural responses. By contrast, the optimized design presents lower bottom surface temperature and better thermal buckling characteristics, performing a better balance between thermal insulation and load-bearing constraints.

Composite sandwich panel with multifunction of load bearing, heat insulation, and thermal protection

2014 ◽  
Vol 49 (25) ◽  
pp. 3077-3087 ◽  
Author(s):  
Changping Yin ◽  
Qing Zheng ◽  
Jingcheng Zeng ◽  
Jinshui Yang ◽  
Jiayu Xiao
Keyword(s):  
Sandwich Panel ◽  
Thermal Protection ◽  
Heat Insulation ◽  
Load Bearing ◽  
Composite Sandwich

Compressive behaviour of a nickel superalloy Superni 263 honeycomb sandwich panel

2018 ◽  
Vol 22 (5) ◽  
pp. 1426-1449
Author(s):  
SS Satheesh Kumar ◽  
M Sudhakara Rao ◽  
I Balasundar ◽  
Amit Kumar Singh ◽  
T Raghu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cell Wall ◽  
Cell Size ◽  
Sandwich Panel ◽  
Thermal Protection ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Compressive Behaviour ◽  
Honeycomb Sandwich ◽  
Core Thickness

Metallic thermal protection systems comprising of sandwich panels consisting of hexagonal honeycomb sandwich structures are envisaged to be used in advanced transportation systems like hypersonic vehicles and reusable launch vehicles. The assessment of compressive mechanical behaviour is necessary to understand the response of sandwich structures to aerothermal loads. The fabrication methodology for realizing Ni based superalloy Superni 263 hexagonal honeycomb sandwich panels is established. This work is aimed at understanding the effect of sandwich panel geometry parameters like hexagonal cell size and core thickness on the out-of-plane flatwise compressive behaviour at room temperature. The ultimate compressive strength decreases with increasing core height irrespective of the cell sizes investigated. The dependence of specific compressive strength on the cell size is established by a power law relationship. The compressed sandwich panels subjected to understand the deformation behaviour indicated the dominance of cell wall bending and occasional fracture, however in the case of sandwich panels with higher core thickness cell wall buckling coupled with shearing at the face sheet vicinity is noticed.

scholarly journals Experimental Investigation of Dynamic Response and Deformation of Aluminium Honeycomb Sandwich Panels Subjected to Underwater Impulsive Loads

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Da-Lin Xiang ◽  
Ji-Li Rong ◽  
Xuan He
Keyword(s):  
High Speed ◽  
Sandwich Panel ◽  
Blast Resistance ◽  
Three Dimensional ◽  
Sandwich Panels ◽  
Core Structure ◽  
Image Correlation ◽  
High Speed Photography ◽  
Full Field ◽  
Deformation Modes

The response of aluminium sandwich panels with three thicknesses’ core subjected to different underwater loading levels has been studied in the fluid-structure interaction (FSI) experiments. The transient response of the panels is measured using a three-dimensional (3D) Digital Image Correlation (DIC) system, along with high-speed photography. The full-field shape and displacement profiles of dry face sheets were recorded in real time compared with those of monolithic plate. The out-of-plane deflection and in-plane strain were quantified and analyzed. Three typical deformation modes of sandwich panel were identified. The results show that the core structure is crushed resulting in an initial large circular shape of deformation in the center area of panels. From this moment on, the panel is starting to act as a free vibration beam with initial velocities. The deformation modes consisted of homogeneous large deformation for both face sheets, obvious deformation border on wet face sheet, core node imprinting, remarkable wrinkled skin of deformation border, and a partial delamination and partial tear failure of the dry face. The blast-resistance of sandwich panel can be highly efficiently improved by increasing the thickness of core structure.

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

Prediction of Sound Transmission Loss for Finite Sandwich Panels Based on a Test Procedure on Beam Elements

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Zhongchang Qian ◽  
Daoqing Chang ◽  
Bilong Liu ◽  
Ke Liu
Keyword(s):  
Sandwich Panel ◽  
Transmission Loss ◽  
Test Procedure ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Expansion Method ◽  
Bending Stiffness ◽  
Sound Transmission Loss ◽  
Modal Expansion ◽  
Beam Elements

An approach on the prediction of sound transmission loss for a finite sandwich panel with honeycomb core is described in the paper. The sandwich panel is treated as orthotropic and the apparent bending stiffness in two principal directions is estimated by means of simple tests on beam elements cut from the sandwich panel. Utilizing orthotropic panel theory, together with the obtained bending stiffness in two directions, the sound transmission loss of simply-supported sandwich panel is predicted by the modal expansion method. Simulation results indicated that dimension, orthotropy, and loss factor may play important roles on sound transmission loss of sandwich panel. The predicted transmission loss is compared with measured data and the agreement is reasonable. This approach may provide an efficient tool to predict the sound transmission loss of finite sandwich panels.

scholarly journals Obtention of Antimicrobial Fibers Type Core/Shell Pla/Pvoh-Lae By Coaxial Electrospinning

2021 ◽  
Author(s):  
C. Patiño Vidal ◽  
E. Velásquez ◽  
M. J. Galotto ◽  
C. López de Dicastillo
Keyword(s):  
Food Packaging ◽  
Thermal Protection ◽  
Average Diameter ◽  
Core Structure ◽  
Coaxial Electrospinning ◽  
Electrospinning Technique ◽  
Active Compounds ◽  
Antimicrobial Materials ◽  
Palabras Clave ◽  
Fatty Food

Coaxial electrospinning (EC) is a technology that allows the encapsulation of active compounds, such as ethyl lauroyl arginate (LAE), in shell/core structures, in order to develop new antimicrobial materials for food packaging that slow down the release of active compounds and extend the food’s shelf life. For this reason, the objective of this study was to develop antimicrobial fibers shell/core type by EC. Two polymers with different hydrophilic character, polylactic acid (PLA) for the shell and polyvinyl alcohol (PVOH) and LAE for the core, were used to obtain PLA/PVOH-LAE fibers and slow the release of the antimicrobial compound. The morphology of fibers was evaluated by optical microscopy and their thermal properties through thermogravimetric analyses (TGA). LAE release studies were carried out in a fatty food simulant (ETOH 95%), and was compared with the minimum inhibitory concentration (MIC) values of LAE against a gram-positive bacteria, Listeria innnocua. The optical micrographs showed the obtaining of the shell/core structure with an average diameter of approximately 0.6 µm, and the TGA analyses demonstrated the thermal protection of LAE by the shell of the fibers. Released LAE reached the equilibrium state in ETOH 95% during the first 3 hours, maintaining a higher concentration than the MIC value obtained in L. innnocua (10 ppm). The results demonstrate that new packaging materials with antimicrobial activity such as PLA/PVOH-LAE polymeric fibers with a shell/core structure can be obtained through the coaxial electrospinning technique. Keywords: coaxial electrospinning, ethyl lauroyl arginate, fibers, shell/core, food packaging. Resumen El electrohilado coaxial (EC) es una tecnología que permite encapsular compuestos activos como el etil lauroil arginato (LAE) en estructuras tipo pared/núcleo con la finalidad de desarrollar nuevos materiales antimicrobianos para el envasado de alimentos que ralenticen la liberación del compuesto y extiendan la vida útil del alimento. Por tal razón, el objetivo de este estudio consistió en desarrollar fibras antimicrobianas tipo pared/núcleo mediante EC. Dos polímeros con distinto carácter hidrofílico como el poli (ácido láctico) (PLA) para la pared y poli (alcohol vinílico) (PVOH) y LAE para el núcleo se utilizaron para obtener las fibras PLA/PVOH-LAE, y ralentizar la liberación del compuesto antimicrobiano. La morfología de las fibras se evaluó mediante microscopía óptica y sus propiedades térmicas mediante análisis termogravimétricos (TGA). Se realizaron estudios de liberación del LAE en un simulante de alimentos graso (ETOH 95%), y se comparó con la concentración mínima inhibitoria (MIC) hacia una bacteria Gram positiva Listeria innnocua. Las micrografías ópticas evidenciaron la obtención de la estructura pared/núcleo con un diámetro promedio de 0,6 µm aproximadamente, y el análisis TGA demostró la protección térmica del LAE por la pared de las fibras. El LAE liberado alcanzó el estado de equilibrio en ETOH 95% durante las 3 hr iniciales, manteniendo una concentración superior a la MIC obtenida para L. innnocua (10 ppm). Los resultados demuestran que nuevos materiales de envase con actividad antimicrobiana como fibras poliméricas PLA/PVOH-LAE con estructura pared/núcleo pueden ser obtenidos mediante la técnica de electrohilado coaxial. Palabras clave: electrohilado coaxial, etil lauroil arginato, fibras, pared/núcleo, envase de alimentos.

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