Papers by Author: Xiao Yan Tong

Abstract: Finite element model of folding wings was designed in the light of structural scheme, and each part of the model used composites. Different aeroelastic analysis models were built from emission to cruise, and then the models were made the study focus on flutter analysis. The result showed the change relationship of the critical flutter speed of wings and flutter frequency with sweep angle in state of expansion process, and the change relationship of the critical flutter speed of wings and flutter frequency of folding wings with cruising altitude and cruise Mach number in state of cruise. The whole flight state was analyzed if the folding wings might flutter, and if it took place the structure optimization of wings was needed. Simulation results have a certain guiding significance for practical engineering application.

Abstract: Folding wings of UAV may lead to high bending and torsion deformation under flight load. In order to solve the problem, an improved folding wing mechanism is proposed, which makes support mechanism stiffness become enough big. By means of CATIA and ADAMS, a virtual prototype is set up, which can simulate dynamics of the deployment mechanism. Therefore the relationship among deployment time and friction coefficient and tension is arrived. Meanwhile finite element analysis is made on folding wing with support structure and without support structure by MSC.Nastran. And the results show that the stiffness and strength change obviously. Simulation results have a certain guiding significance for practical engineering application.

Abstract: An experimental study was carried out to study the low-velocity impact characteristics and the influence of impact energy on the damage of plain woven carbon fiber reinforced silicon carbide composite. Visual, ultrasonic scanning, X-ray, industrial CT and infrared thermal imaging were then utilized respectively for Nondestructive Testing of the test specimens after impact test. The results show that the material damage area increase significantly with the increase of the impact energy. But as the specimen is run through, when the impact energy comes to12J, the damage area decrease. Compare the changing curves of the damage areas obtained by different detection methods, we can find that the changing trends of the damage areas obtained by ultrasonic C-scan and infrared thermal imaging are the same with the impact energies, indicating that the damage of the specimen are more credible by the two methods.

Abstract: In the light of growing global competition, organizations around the world today are constantly under pressure to produce high-quality products at an economical price. The integration of design and manufacturing activities into one common engineering effort has been recognized as a key strategy for survival and growth. Design for manufacturability (DFM) requires product designers to simultaneously consider the manufacturing issues of a product along with the geometrical and design aspects. In this paper, part manufacturability was analyzed in detail. An evaluation system of DFM was proposed. Product design can be guided according to feedback information by evaluating the part manufacturability.

Abstract: The aim of this paper is to study the influence of manufacturing defects on coefficient of thermal expansion (CTE) of Plain Weave C/SiC by using the finite element computational micromechanics (FECM) method. Utilizing photomicrographs taken by scanning electron microscope (SEM), we established an accurate representative volume element (RVE) model for the plain weave C/SiC composites with consideration of manufacturing defects, which have different influence on CTE. The study shows that matrix cracks make CTE increase by 2.7% and matrix porosities make CTE decrease by 2.4% compared with the no defects RVE model. The variation law of CTE along with cracks density and porosity volume is also obtained: CTE of plain weave C/SiC is decreasing correspondingly while the speed gradually slows with the increasing of matrix crack density and matrix porosity volume fraction.

Abstract: In the light of growing global competition, organizations around the world today are constantly under pressure to produce high-quality products at an economical price. The integration of design and manufacturing activities into one common engineering effort has been recognized as a key strategy for survival and growth. Design for manufacturability (DFM) requires product designers to simultaneously consider the manufacturing issues of a product along with the geometrical and design aspects. In this paper, part manufacturability was analyzed in detail. An evaluation system of DFM was proposed. Product design can be guided according to feedback information by evaluating the part manufacturability.

Abstract: Utilized photomicrographs taken by scanning electron microscope (SEM), an accurate representative volume element (RVE) model for plain weave C/SiC composites is established. Based on the steady-analysis method, the in-plane and thickness direction thermal conductivity of the C/SiC composites are calculated as 25.6Wm-1K-1 and 12.1Wm-1K-1, respectively. The manufacturing flaws have different effect on thermal conductivity. Compared with RVE without flaws, the result shows that matrix cracks make thermal conductivity decrease by 7.2% in the in-plane direction and have little effect in the thickness direction; matrix porosities have a significant effect on thermal conductivity, which make the thermal conductivity decrease by 16.7% in the in-plane direction and decrease by 25.4% in the thickness direction. The variation law of thermal conductivity along with porosity volume is also observed: as matrix porosity volume fraction is increasing, the thermal conductivity of material shows significant decrease.

Abstract: Lightweight design was carried out in order to meeting the requirement of long endurance. Structure form was designed based on loading characteristics. Rationality of structure form was verified by finite element method and static tests, which proved deformation of wing measuring up mechanical properties of cell panel. Finite element modal analysis was performed. Then mode test was carried to correcting analysis results. Low order modes by testing are coincided with that computed in finite element method (FEM).

Abstract: This paper is to explain the application of DELMIA in 3D digital virtual assembly. It takes ARJ21 aircraft central wing assembly simulation process as an example. It introduces the related modules of DELMIA software and discusses the application of DELMIA in aircraft assembly simulation through the central wing assembly process simulation and human task simulation in the ARJ21 aircraft central wing assembly simulation.

Abstract: This work evaluated a new ultra-light photovoltaic embedded structure for solar-powered aircrafts, in which the mono-crystalline silicon (m-Si) solar cells encapsulated by epoxy were adhesively bonded to the upper wing skin made of rigid polyurethane foam (RPUF). To evaluate the effect on the cell encapsulation, static tests were carried out. The results showed that the encapsulated cells had better flexibility. The bonded-point and multi-cell models for the embedded structure were analyzed by FEA software. As the number of the bonded points increasing, the stress and deformation of the embedded structure decreased; once exceeded 16 points, the stress and deformation changed little. The deformation of the non-reinforced multi-cell model was very large; the stiffness improved greatly after reinforced by the glass fiber ribbons.