scholarly journals Manufacturing process, mechanical behavior and modeling of composites structures sandwich panel

2021 ◽  
Vol 13 (1) ◽  
pp. 183-191
Author(s):  
Adriana STEFAN ◽  
George PELIN ◽  
Cristina-Elisabeta PELIN ◽  
Alexandra-Raluca PETRE ◽  
Monica MARIN
Keyword(s):  
Mechanical Behavior ◽  
Technological Process ◽  
Manufacturing Process ◽  
Sandwich Structure ◽  
Sandwich Panel ◽  
Sandwich Structures ◽  
Point Of View ◽  
Structural Approach ◽  
Experimental Basis ◽  
Sandwich Construction

The complexity of sandwich structures is a challenge for aeronautics designers. Sandwich construction is widely used in both the aerospace and commercial industries because it is an extremely lightweight structural approach with high rigidity and strength/weight ratios. Although today's technology offers the possibility to combine a variety of materials for these structure solutions, in aviation only a few materials are accepted. This paper presents the technological process of making these sandwich structures, as well as a study of the characterization and testing of a sandwich structure to analyze the behavior from a mechanical point of view. The conclusions of the paper represent an experimental basis on which further research will be built.

A combined experimental-numerical analysis of a novel deformable sandwich structure for morphing wing applications

2020 ◽  
pp. 109963622097931
Author(s):  
Amin Hajarian ◽  
Mohammad Reza Zakerzadeh ◽  
Hamid Salehi ◽  
Mostafa Baghani
Keyword(s):  
Numerical Analysis ◽  
Mechanical Behavior ◽  
Numerical Method ◽  
Cantilever Beam ◽  
Manufacturing Process ◽  
Sandwich Structure ◽  
Numerical Results ◽  
Experimental Results ◽  
Morphing Wing ◽  
Comprehensive Review

In this paper, a new flexible sandwich structure is introduced, which can be employed in morphing aircrafts capable of intelligently changing their shape in different flight conditions. To accomplish this goal, first, a review of the various ideas in the literature is presented. In the following, features of the proposed structure and its differences from other ideas are expressed. Then, the process of fabrication and the various stages of shaping the structure are described. In an aircraft with variable wings camber, the deformable section can be assumed to be a cantilever beam. Thus, samples of the proposed structure are fabricated as the cantilever beam and are tested as tip-loaded beams. Since the numerical analysis of the new structure involves the recognition of the mechanical behavior of its components, a comprehensive review of the mechanical behavior of each component of the structure is performed. Afterwards, the numerical method is utilized to model samples of the structure, and the changes in the samples’ deformation are examined under different loads. According to the observation of the broken samples, to arrive at more accurate numerical results, a distribution for the cavities, caused by the manufacturing process, is considered. Finally, with the same assumptions, another sample is analyzed, and it is shown that the results of the second model are consistent with experimental results.

scholarly journals The energy absorption behavior of novel composite sandwich structures reinforced with trapezoidal latticed webs

2021 ◽  
Vol 60 (1) ◽  
pp. 503-518
Author(s):  
Juan Han ◽  
Lu Zhu ◽  
Hai Fang ◽  
Jian Wang ◽  
Peng Wu
Keyword(s):  
Bearing Capacity ◽  
Energy Absorption ◽  
Sandwich Structure ◽  
Ultimate Load ◽  
Sandwich Structures ◽  
Elastic Displacement ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Composite Sandwich ◽  
Composite Sandwich Structures

Abstract This article proposed an innovative composite sandwich structure reinforced with trapezoidal latticed webs with angles of 45°, 60° and 75°. Four specimens were conducted according to quasi-static compression methods to investigate the compressive behavior of the novel composite structures. The experimental results indicated that the specimen with 45° trapezoidal latticed webs showed the most excellent energy absorption ability, which was about 2.5 times of the structures with vertical latticed webs. Compared to the traditional composite sandwich structure, the elastic displacement and ultimate load-bearing capacity of the specimen with 45° trapezoidal latticed webs were increased by 624.1 and 439.8%, respectively. Numerical analysis of the composite sandwich structures was carried out by using a nonlinear explicit finite element (FE) software ANSYS/LS-DYNA. The influence of the thickness of face sheets, lattice webs and foam density on the elastic ultimate load-bearing capacity, the elastic displacement and initial stiffness was analyzed. This innovative composite bumper device for bridge pier protection against ship collision was simulated to verify its performance. The results showed that the peak impact force of the composite anti-collision device with 45° trapezoidal latticed webs would be reduced by 17.3%, and the time duration will be prolonged by about 31.1%.

Material Selection for CFRP-Aluminium-Foam-Sandwiches Manufactured by a PUR Spraying Process

2017 ◽  
Vol 742 ◽  
pp. 317-324
Author(s):  
Peter Rupp ◽  
Peter Elsner ◽  
Kay André Weidenmann
Keyword(s):  
Manufacturing Process ◽  
Sandwich Structures ◽  
Bending Stiffness ◽  
Effective Density ◽  
Sandwich Composites ◽  
Open Cell ◽  
The Core ◽  
Bending Modulus ◽  
The Face ◽  
Spraying Process

Sandwich structures are ideal for planar parts which require a high bending stiffness ata low weight. Usually, sandwich structures are manufactured using a joining step, connecting theface sheets with the core. The PUR spraying process allows to include the infiltration of the facesheet fibres, the curing of the matrix and the joining of the face sheets to the core within one processstep. Furthermore, this manufacturing process allows for the use of open cell core structures withoutinfiltrating the core, which enables a comparison of different material configurations, assembled bythe same manufacturing process. The selection of these materials, with the aim of the lowest possiblemass of the sandwich composite at a constant bending stiffness, is displayed systematically within thiswork.It could be shown that the bending modulus calculated from the component properties matched theexperimentally achieved values well, with only few exceptions. The optimum of the bending modulus,the face sheet thickness and the resulting effective density could be calculated and also matched theexperimental values well. The mass-specific bending stiffness of the sandwich composites with corestructures of open cell aluminium foams was higher than with closed cell aluminium foams, but wasexceeded by sandwich composites with Nomex honeycomb cores.

scholarly journals Theories and heat pulse experiments of non-Fourier heat conduction

2016 ◽  
Vol 7 (2) ◽  
pp. 150-166 ◽  
Author(s):  
Péter Ván
Keyword(s):  
Heat Conduction ◽  
Heat Pulse ◽  
Theoretical Background ◽  
Point Of View ◽  
Experimental Basis ◽  
Equilibrium Thermodynamics ◽  
Fourier Heat Conduction ◽  
Non Equilibrium

Abstract The experimental basis and theoretical background of non-Fourier heat conduction is shortly reviewed from the point of view of non-equilibrium thermodynamics. The performance of different theories is compared in case of heat pulse experiments.

Sandwich Structures for Naval Ships: Design and Experience

2000 ◽  
Author(s):  
Karl-Axel Olsson
Keyword(s):  
Lightweight Design ◽  
Weight Ratio ◽  
Point Of View ◽  
Economic Point ◽  
Plastic Foams ◽  
Reinforced Plastics ◽  
Sandwich Construction ◽  
Glass Fibre Reinforced Plastic ◽  
Glass Fibre Reinforced ◽  
Common Face

Abstract In Sweden we have a long experience with different types of vehicles and ships in sandwich construction, especially Navy ships such as minesweepers, mine-counter-measure-vessels and corvettes. GRP (Glass fibre Reinforced Plastic) and FRP (Fibre Reinforced Plastics) have been the most common face materials, but metallic materials such as Al-alloys, coated carbon steel and stainless steel have also been used. Core materials have usually been cellular plastic foams of cross-linked PVC (Polyvinyl-chloride), but also extruded PS (Poly-styrene), PUR (Poly-urethane), PEI (Poly-ether-imide) and PMI (Poly-methacryl-imide). Different continuous and discontinuous manufacturing processes have been used. Vacuum assisted infusion has been introduced recently, because it is a closed process, gives high fibre content and a good quality of the laminates. Sandwich design has mainly been used in the transportation area, where lightweight design is needed to give higher performance and load bearing capacity. The use of sandwich construction will give high stiffness- and strength-to weight ratio. This is usually not enough from an economic point of view to justify the introduction of sandwich construction, but other integrated functions must be considered, i.e. insulation, energy consumption, damping, fewer components, lower manufacturing costs, low maintenance, signature effects (military) etc.

Geometric recognition methodology of honeycomb structure based on dynamic window

2020 ◽  
pp. 109963622091172
Author(s):  
Wei Zhou ◽  
Wanhui Wei ◽  
Zhonggang Wang ◽  
Can Cui
Keyword(s):  
Quality Assessment ◽  
Manufacturing Process ◽  
Sandwich Structure ◽  
High Standard ◽  
Honeycomb Structure ◽  
Maximum Average Degree ◽  
Honeycomb Cell ◽  
Degree Deviation ◽  
Relationship Of

Defect determination is important for guaranteeing the quality of sandwich structure. The present study, a geometric recognition methodology based on dynamic window was constructed for honeycomb structure, by identifying the vertices from given images captured in the manufacturing process. The combination of traversing window, annihilation window, and tracking window was developed to reconstruct the contoured maximums, locate the vertices positions, and determine the cell–node relationships, respectively. Moore boundary tracking was practically used to deal with the problem caused by the edge effect. Based on these, all relevant vertices as well as their relationship of each honeycomb cell can be determined. Afterward, quality assessment of the honeycomb product was carried out in terms of the maximum, the average, and the maximum average degree deviation. Illustrations validate the present methodology well. All these achievements shed a light on design of the consistency, reliability, and homogeneity of high-standard sandwich structure.

scholarly journals Occurrence of Furosine and Hydroxymethylfurfural in Breakfast Cereals. Evolution of the Spanish Market from 2006 to 2018

Foods ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 158 ◽  
Author(s):  
Marta Mesías ◽  
Laura Sáez-Escudero ◽  
Francisco J. Morales ◽  
Cristina Delgado-Andrade
Keyword(s):  
Manufacturing Process ◽  
Protein Quality ◽  
Sugar Content ◽  
Point Of View ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Breakfast Cereal ◽  
Breakfast Cereals ◽  
Damage Indices ◽  
Amadori Compounds

The demand for healthier products has led the breakfast cereal sector to develop new formulations to improve the nutritional profile of breakfast cereals; however, the increase in chemical risks should also be evaluated. Amadori compounds and 5-hydroxymethylfurfural (HMF) are Maillard reaction products applied as heat damage indices in breakfast cereals. Furosine (a synthetic amino acid formed by acid hydrolysis of Amadori compounds) is linked to the loss of protein quality, while HMF has exhibited toxicological effects in cells and animals. Furosine and HMF content was evaluated in Spanish breakfast cereals whereas the effect of protein, fibre, and sugar content, the type of grain, the presence of honey, and the manufacturing process were discussed, as well as compared with a previous prospective study. The average furosine and HMF contents were 182 mg/kg and 21.7 mg/kg, respectively. Protein and fibre content were directly related to the furosine content, whereas sugar level, honey addition, and the manufacturing process affected the content of HMF. Occurrence of furosine and HMF decreased nearly 40% in a decade (2006–2018). These findings are relevant in terms of nutritional score, since lysine availability is preserved, but also from a toxicological point of view, due to the decreased daily exposure to both compounds, which dropped 30%.

scholarly journals Thermomechanical Performance of Bio-Inspired Corrugated-Core Sandwich Structure for a Thermal Protection System Panel

2019 ◽  
Vol 9 (24) ◽  
pp. 5541 ◽  
Author(s):  
Vinh Tung Le ◽  
Nam Seo Goo
Keyword(s):  
Sandwich Structure ◽  
Thermal Protection ◽  
Sandwich Structures ◽  
High Strength ◽  
Thermal Protection System ◽  
Boundary Layer Transition ◽  
Protection System ◽  
Aerodynamic Heating ◽  
Dense Structure ◽  
Skin Structure

A skin structure for thermal protection is one of the most interesting components that needs to be considered in the design of a hypersonic vehicle. The thermal protection structure, if a dense structure is used, is heavy and has a large heat conduction path. Thus, a lightweight, high strength structure is preferable. Currently, for designing a lightweight structure with high strength, natural materials are of great interest for achieving low density, high strength, and toughness. This paper presents bio-inspired lightweight structures that ensure high strength for a thermal protection system (TPS). A sinusoidal shape inspired by the microstructure of the dactyl club of Odontodactylus scyllarus, known as the peacock mantis shrimp, is presented with two different geometries, a unidirectionally corrugated core sandwich structure (UCS) and a bidirectionally corrugated core sandwich structure (BCS). Thermomechanical analysis of the two corrugated core structures is performed under simulated aerodynamic heating, and the total deflection and thermal stress are presented. The maximum deflection of the present sandwich structure throughout a mission flight was 1.74 mm for the UCS and 2.04 mm for the BCS. Compared with the dense structure used for the skin structure of the TPS, the bio-inspired corrugated core sandwich structures achieved about a 65% weight reduction, while the deflections still satisfied the limits for delaying the hypersonic boundary layer transition. Moreover, we first fabricated the BCS to test the thermomechanical behaviors under a thermal load. Finally, we examined the influence of the core thickness, face-sheet thickness, and emittance in the simulation model to identify appropriate structural parameters in the TPS optimization. The present corrugated core sandwich structures could be employed as a skin structure for metallic TPS panels instead of the honeycomb sandwich structure.

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