COMPOSITES SCIENCE AND ENGINEERING

STUDY ON VISCOSITY MODEL AND RHEOLOGICAL PROPERTIES OF UPR APPLIED IN VARI PROCESS

ZHANG Man-man , LI Wei

2014, 0(7): 5-9.

Asbtract ( 47 )

PDF (1169KB) ( 84 )

References | Related Articles | Metrics

This paper tested and analyzed the viscosity of DS326PT-1 resin system under dynamic temperature and constant temperature,established the engineering viscosity model and predicted the VARI processing window according to the viscosity model. The results indicated that the experimental viscosity value agreed well with the predicted viscosity,which proved the validity of the model. The viscosity model of the resin system can provide important data for the simulation and parameter optimization of VARI processing.

EXPERIMENTAL INVESTIGATION ON TENSILE PERFORMANCE OF FRP GRIDS AND ITS APPLICATION AS STRENGTHENING MATERIALS FOR UNDERWATER CONCRETE

WEI Yang, JI Jun, ZHANG Min

2014, 0(7): 10-15.

Asbtract ( 48 )

PDF (6744KB) ( 129 )

References | Related Articles | Metrics

With the advantages of lightweight, corrosion resistance, remarkable strengthening effect, FRP grids have good application prospects in the field of civil engineering. However, the manufacturing technology of traditional hand lay-up affects the quality of the products and the stability of their performance and limits their applications in engineering. The technology of Vacuum Assisted Resin Infusion (VARI) was employed and developed to manufacture the FRP grids in this paper, and two types of FRP grids made of basalt fiber and carbon fiber were manufactured. The corresponding three kinds of tensile specimens cut from the FRP grids were tested. The experimental results indicate that the elastic modulus of FRP grids is stable, whereas the ultimate strength and ultimate strain show large deviation. With the increasing of the fibers of FRP grids, the failure probability due to defects of fibers increases, and the available strength and strain ability decrease, and the elastic modulus is not significantly varied. The different FRP grids reinforced with various types of fibers exhibit different mechanical properties. Basalt fiber reinforced plastic grids have lower ultimate strength and elastic modulus than carbon fiber reinforced plastic grids, but the former has larger ultimate strain than the latter. The effectiveness of underwater concrete columns strengthened with FRP grids was validated, and the strengthened columns have a significant increase in load carrying and deformation ability.

STUDY FOR MECHNICAL PROPERTIES OF THE COMPOSITE LAMINATES EMBEDDED WITH THE OPTICAL FIBERS

LIU Gang, ZHANG Bin, ZHOU Yu-jing, LI Wei-dong

2014, 0(7): 16-22.

Asbtract ( 56 )

PDF (3049KB) ( 87 )

References | Related Articles | Metrics

In this paper, Fiber Bragg Grating (FBG) was embedded into the composite laminates and the effect of the number of the FBG on the tensile and compression properties of the composite laminates were studied, also the micrograph of interlayer. Furthermore, the embedded FBGs were used as the sensors to monitor the tensile strains and compared with the strain gage. It was shown that, when FBGs were embedded into the laminates along the fiber direction, the 0° tensile strength and modulus of the composites were slightly declined. Whereas, when FBGs were embedded into the laminates perpendicular to the fiber direction, the 90° tensile strength and modulus of the composites were slightly increased. For the compression performance, because of the broken-down strength of FBG was lower which will induced the stress concentration inside the composite laminates, and therefore lead to the decrease of the compression properties. It was shown from the micrographs of interlayer that when FBGs were embedded perpendicular to the fiber direction, resin-rich area will be clearly observed around the FBGs.

PREDICTING MACROSCOPIC EFFECTIVE ELASTIC PROPERTIES OF COMPOSITE LAMINATED PLATE BY HOMOGENIZATION FEM

XIE Gui-lan, ZHAO Jin-xiao, TIAN Jie, WU Tao

2014, 0(7): 23-27.

Asbtract ( 91 )

PDF (1435KB) ( 170 )

References | Related Articles | Metrics

This paper puts forward the effective elastic modulus definition of composite materials based on equivalent energy principle for the first time. By the small parameter gradual homogenization theory , deducing the equivalent elastic tensor of composite laminated plate and by combining with finite element method (FEM) to establish a multi-scale model of composite laminated plate, we could predict the macroscopic effective elastic modulus of carbon nanotubes and nanofilm laminated composite material. By the homogenization method to obtain macro average of elastic modulus, and put it in the commercial software ANSYS system, coupled with two scales of the macro and micro, we could analysis the equivalent elastic performance of composite laminated plate. The conclusions are of significance for guiding the preparation of new composites.

STRESS ANALYSIS OF A GFRP TANK UPON LOW-TEMPTERATURE ENVIRONMENT AND LIQUID FREEZING

LI Yue, ZHU Si-rong, WEN Huan, CHEN Jian-zhong

2014, 0(7): 28-32.

Asbtract ( 48 )

PDF (4068KB) ( 69 )

References | Related Articles | Metrics

According to the mesoscopic mechanics analysis on thermal expansion coefficients of composite materials, the thermal expansion coefficients of different layers in a GFRP tank are determined. Stress of the GFRP tank upon low-temperature environment and liquid freezing is simulated by using ANSYS. The change laws of the stresses and strains upon different ice thickness are discussed. The results show that additional stress is generated by low temperature and liquid freeze. There is no obvious difference between the stress and strain upon different ice thickness due to different thickness of the GFRP tank at different places. When being used in low temperature environments, it is recommended that low temperature and freezing condition should be involved in tank-design.

THE FINITE ELEMENT ANALYSIS OF THE BEST PRETENSION OF THE COMPOSITE PRESSURE VESSEL

DONG Wen-wu , WANG Peng-fei, LI Yang, HE Ke-bin

2014, 0(7): 33-36.

Asbtract ( 62 )

PDF (1484KB) ( 85 )

References | Related Articles | Metrics

The paper analyzes the stress of the composite pressure vessel under internal pressure by ANSYS. The results show that the vessel lining stress will be significantly reduced when applying preloaded forces, and the stress distribution will become more uniform, the utilization of the strength of the carbon fiber is improved, as well the fatigue life of the vessel.

THE DOOR STIFFNESS RESEARCH OF CIVIL AIRCRAFT

YUAN Xiu-qi

2014, 0(7): 37-41.

Asbtract ( 54 )

PDF (1460KB) ( 87 )

References | Related Articles | Metrics

Based on the structural characteristics of a class of typical civil aircraft door, several sandwich structures are designed and compared. Several conditions of sandwich structure are considered, i.e. structure of different inner and outer skin thickness, structure of different honeycomb height, structure of adding and no reinforcing plate, structure with and without honeycomb groove and raising the height of the local cellular. A finite element model of the honeycomb sandwich door is developed. A contrastive analysis of distorted displacement for different structure is obtained. The calculation implies that the thickness of inner skin and honeycomb height plays a dominant role on the door stiffness, and that there is a certain inner skin thickness and honeycomb height for the door, which will make door′s bending deformation in cruise state meet the requirement. The analysis results and conclusion provide some design guide and reference value for the same kind of aircraft door.

LOW-VELOCITY IMPACT AND POST-IMPACT BENDING PERFORMANCE OF STITCHED BRAIDED COMPOSITES

LIANG Qian-nan, YAN Jian-hua

2014, 0(7): 42-46.

Asbtract ( 45 )

PDF (5835KB) ( 106 )

References | Related Articles | Metrics

In this paper, two kinds of stitched braided composites with similar thicknesses were prepared. They were consisted of two thick braided sheets and four thin braided sheets respectively. This paper analyzed surface and internal damage characteristics and distribution in the composites induced by impacting and post-impact bending test, and explored their post-impact bending properties. The results are discussed. In the case of the impact energy in 3.2J/mm, the damage of stitched braided composites of four thin braided sheets are more serious than that of stitched braided composites of two thick braided sheets. In post-impact bending test, resin cracks can be hardly observed between adjacent braided sheets on the compression face. Meanwhile, resin cracks on the tension face extend along the cracks induced by impacting; bending strength and modulus of stitched braided composites of four thin braided sheets are greater than that of stitched braided composites of two thick braided sheets. But, its bending fracture deformation is less than that of the later.

STUDY ON CURING CHARACTERISTICS OF UNSATURATED POLYESTER RESIN WITH TBPB/TBPO

NI Qiu-ru, ZHOU Quan, NI Li-zhong, DONG Qing-zhi

2014, 0(7): 47-49.

Asbtract ( 52 )

PDF (1007KB) ( 82 )

References | Related Articles | Metrics

The curing behavior of unsaturated polyester with complex initiation system TBPB/TBPO was studied by dynamic DSC. The effects of curing system by different content of TBPO were compared. With the increase of content of TBPO from 10% to 100%, the curing temperature was decreased from 142℃ to 120.8℃. Simultaneously, the gel time was reduced from 214s to 79.5s and the cure time were found to decrease from 634.4s to 171.5s.

THERMAL PROPERTY OF SILICON CARBIDE USED AS THERMAL LAYER OF WIND TURBINE BLADE MOLD

LI Yi-quan, PANG Zeng-kai, CHENG Wang-kang, ZHANG Zuo-chao

2014, 0(7): 50-52.

Asbtract ( 51 )

PDF (1247KB) ( 76 )

References | Related Articles | Metrics

A type of glass fiber reinforced epoxy composite was prepared to simulate wind turbine blade using vacuum infusion molding process. Silicon carbide (SIC) was used as thermal layer in the blade. The thermal conductivity of silicon carbide granularity was studied. When the mass ratio of 220 mesh to 100 mesh silicon carbide was 1∶1, SiC exhibit uniform thermal conductivity. When the viscosity value of the SiC/epoxy system was 2.9 Pa·s, the system was able to be used as a blade mold thermal layer for its decent property of scraping. When SIC was applied to the blade mold, the average surface temperature of the mold was 63℃, and the overall temperature distribution was uniform.

THE COMBINED SURFACE PROPERTIES OF RTM COMPOSITES WITH CO-CURINIG

LUO Hai-tao, LI Ya-na, KANG Yong-qing

2014, 0(7): 53-56.

Asbtract ( 51 )

PDF (5536KB) ( 118 )

References | Related Articles | Metrics

This paper studied the combined surface of structure composite materials by RTM, tested and analyzed the combined surface properties of different formed ways. Finally, an optimal pre-forming method was determined.

INVESTIGATION ON IMPACT AND POST-IMPACT FLEXURAL PROPERTY OF 3D FIVE-DIRECTION BRAIDED CARBON/GLASS HYBRID EPOXY COMPOSITES

FANG Dan-dan, YAN Jian-hua

2014, 0(7): 57-61.

Asbtract ( 54 )

PDF (3835KB) ( 99 )

References | Related Articles | Metrics

The impact property and residual flexural property of three-dimensional (3D) five-direction braided glass/carbon hybrid epoxy composites after impact was studied. In this work, the drop weight impact test and three point bending test were conducted. The results indicate that, after the drop weight impact test, the impact surface is less damaged than the back surface. In the back surface, the disperse of the cracks was mainly along the longitudinal direction, and the three point bending test shows that the flexural modulus of glass fiber composites is increased when mixed with carbon fibers. When the axial yarn arrangement were CF∶GF∶CF, the impact resistance of the hybrid composite is the best. The property of impact resistance is related to hybrid methods.

STUDY OF SEALING TO PREVENT OIL LEAKAGE FOR THE THERMOPLASTIC CYLINDER HEAD COVER

WANG Jing, YANG De-xu, SONG Lei, CUI Qiao-li

2014, 0(7): 62-64.

Asbtract ( 53 )

PDF (2043KB) ( 90 )

References | Related Articles | Metrics

Oil leakage of engine cylinder head cover is one of the important problems that influences the engine performance and the overall vehicle performance. In this paper, the principle of cylinder head cover permeability was studied. And the influencing factors affecting the performance of the head cover sealing deformation forms, gaskets structural design and hardness, bolt preload and other major factors were analyzed systematically. Finally, the anti-leakage solutions were proposed.

STUDY ON COMPOSITE MULTI-FREQUENCY SELECTIVE SUB-REFLECTOR OF ANTENNA

WANG Hai-dong, LI Jin-liang, NING Xiao-lei, JIN Chao

2014, 0(7): 65-68.

Asbtract ( 47 )

PDF (1021KB) ( 80 )

References | Related Articles | Metrics

After optimization of envelop materials, sandwich materials and bonding materials, the composite of wave transparent materials have been proposed and adopted, which can be suitable for frequency selective surface of sub-reflectors with S/X/Ku/Ka four bands. Forming technologies of precisely curved dipole oscillator, which has good processing stability and high yield, were applied based on the research of curved oscillator forming and sub-reflector forming. A four-band frequency selective surface of sub-reflectors was obtained with the accuracy of 0.08mm (r.m.s) and the transmission loss of less than 0.25dB at S/Ku-band.

INFLUENCE OF 3D BRAIDING STRUCTURE PARAMETERS ON TENSILE PROPRETIES OF COMPOSITES

LI Su-hong, LIU Li-fang, YAN Jian-hua, YU Jian-yong

2014, 0(7): 69-73.

Asbtract ( 37 )

PDF (3020KB) ( 75 )

References | Related Articles | Metrics

In this paper, based on seven experimental comparisons and analyses, the influences of three dimensional braiding structure parameters (such as braiding angle, fibre volume fraction, the number of axial yarns to the number of braiding yarns ratio, 3D four-directional/five-directional, thickness) on tensile properties of composites are evaluated, and the failure mode of composites is studied. The results show that the 3D braided composites have good tensile performance, and the yarn braiding angle, composites size, fibre volume fraction and the number of axial yarns to the number of braiding yarns ratio are important factors to the improvement of properties. Moreover, composites have two kinds of failure modes: one is the crack propagation along the fibre bundles, another is bundle fracture. And, the latter is the main failure mode. These results provide a basis for the design of 3D braided composites.

THE STUDY ON THE TORSIONAL PROPERTIES OF THE CARBON FIBER COMPOSITE DRIVE SHAFT

CUI Guang-qun, XIAO Wen-gang, WANG Peng-fei

2014, 0(7): 74-77.

Asbtract ( 72 )

PDF (2018KB) ( 138 )

References | Related Articles | Metrics

A composite transmission shaft is designed in this paper, which can withstand 100kN·m torque. The study is based on the torsional properties of the carbon fiber composite drive shaft, and the influence of the ply angle and the ply thickness on torsion property of drive shaft is explained in this paper, and its static torsional properties and the critical buckling load is also checked by the finite element method.

THE APPLICATION RESEARCH OF RESIN-BASED COMPOSITES FOR AERO-DYNAMIC THERMAL PROTECTION SYSTEM

JIANG Ling-lan, CHEN Yang

2014, 0(7): 78-84.

Asbtract ( 69 )

PDF (5837KB) ( 92 )

References | Related Articles | Metrics

Resin-based composites have become the basic materials of the Aero-dynamic thermal protection system. In this paper, the present applications,the development tendency and the requirements of resin-based composites in the Aero-dynamic thermal protection system were presented. And, the problems to be solved about high performance,low cost,integration of design and evaluation in resin-based composite materials were discussed.

GENERAL OVERVIEW ABOUT ROOT JOINT OF WIND TURBINE BLADE

WU Sheng-jun, SHI Jun-hu, PEI Peng-yu

2014, 0(7): 85-87.

Asbtract ( 51 )

PDF (1881KB) ( 451 )

References | Related Articles | Metrics

The root joint of composite wind turbine blade is the only and pivotal component to connect blade and hub of rotor. All the loads applied on the blade are transferred to the hub through the root joint, so the approaches of root joint affected the length of blade and carrying capacity definitely. By exploring the root joint of wind turbine blade, this overview conducts research on three approaches of root joints on current market and analyzes the manufacturability and structural characters of the three approaches of root joints.

Table of Content