Harbin FRP Institute

Harbin, China

Harbin FRP Institute

Harbin, China

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Yang L.,Beihang University | Yan Y.,Beihang University | Kuang N.,Harbin FRP Institute
Polymer Testing | Year: 2013

The low velocity impact performance of domestic aramid fibre reinforced laminates is investigated experimentally and numerically. Laminates with different thicknesses are impacted by drop-weight test machine under different impact energies. The time histories of impact force are recorded and ultrasonic C-scan technology is used to inspect the internal damage of the laminates. Numerical simulation is conducted using finite element method (FEM), taking into account both intralaminar and interlaminar damage. The intralaminar damage model is based on the continuum damage mechanics (CDM) approach, which consists of the strain-based Hashin failure criteria and the exponential damage evolution law, and considers the nonlinear shear behaviour of the material. The interlaminar damage is simulated by interface elements with cohesive zone model. The numerical results show good agreements with the experiments, thus verifying the validity of the presented numerical model. © 2013 Elsevier Ltd. All rights reserved. Property modelling.

Ran Z.,Beihang University | Yan Y.,Beihang University | Li J.,Beihang University | Cong Q.,China Academy of Space Technology | And 2 more authors.
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2014

To solve thermal stress induced delamination in composite laminates that used in flying vehicles, experimental tests and numerical analysis were carried out. Bilinear controlled cohesive elements were adopted to simulate the delamination in laminates, quadratic failure criterion was used to predict the initiation of stiffness softening process, and power law criterion was applied to determine the delamination propagation under mix-mode fractures. The mechanical and thermal expansion properties of lamina applied in those numerical models were tested at high temperature (70°C), room temperature (23°C) and low temperature (-50°C) respectively. The delamination experiments were carried out by use of apparatus DIL-402C. Each composite laminate experienced a same temperature changes, and the maximum temperature difference was 120°C. After experiments, the laminates in given plies were found that delamination appeared in their mid-ply in both ends. Comparisons were made between experimental results and numerical analysis. Compared results show that the predicted delamination zone was well according with the experimental results, which would certify the rightness and reliability of this analysis method.

Chen X.,Harbin Institute of Technology | Xie H.,Harbin Institute of Technology | Chen H.,Harbin FRP Institute | Zhang F.,Shanghai Maritime University
International Journal of Material Forming | Year: 2010

The temperature and the degree of cure of carbon fiber reinforced polymer (CFRP) are coupled during pultrusion. In this paper, the governing equations for heat transfer and resin curing are solved by the combination of finite element method, finite different method and indirect decoupling method. The kinetic parameters needed for simulation are obtained from differential scanning calorimetry (DSC) measurement. The temperature of composites on real time during pultrusion is monitored by the fiber Bragg grating (FBG) sensor. And the final degree of cure of composites is also measured through Sorbitic extraction. It shows that the simulation procedure is effective and reliable and predicts temperature and degree of cure which are in good agreement with the experimental results. On the basis of the simulated results, the relationship between processing parameters and degree of cure is formed by artificial neural network. And genetic algorithm combines with the artificial neural network to solve the bi-objective optimization for CFRP pultrusion. It shows that there are considerable improvements in pull speeds and die temperatures after optimization by ANN and GA. © 2010 Springer/ESAFORM.

Lin Z.,Harbin Institute of Technology | Lin Z.,Harbin FRP Institute | Du S.,Harbin Institute of Technology | Liang Y.,Harbin FRP Institute | And 4 more authors.
Polymers and Polymer Composites | Year: 2011

This work studies the static mechanical properties of grid stiffened polymer composites. This developed composite is expected to have an ultra-higher mechanical performance than traditional composite structures. Static mechanical measurements show that the combination of gridding reinforcement and epoxy polymer (Diglycidyl 4,5-epoxy cyclohexane-1,2-dicarboxylate) helps the advanced composite to possess extremely high mechanical properties, such as resistive properties in axial pressure (more than 160% improvement) and external pressure (more than 102% improvement) for comparison. Subsequently, the effects of wetting angle of reinforcement, quantity of gridding reinforcement, and type of grid on the mechanical properties of the advanced polymer composites have been studied and analyzed. Finally, the finite element model (FEM) method is employed to substantiate these experimental results. The FEM simulation results are in such great agreement with the experimental results that the standard deviations between them are strictly limited to 15%. Furthermore, it demonstrates that the FEM technology is an effective approach for predicting and optimizing structure design, as well as the mechanical behaviors. © Smithers Rapra Technology, 2011.

Xie W.,Harbin Institute of Technology | Zhang W.,Harbin Institute of Technology | Kuang N.,Harbin FRP Institute | Li D.,Harbin Institute of Technology | And 5 more authors.
Composites Part B: Engineering | Year: 2016

In this work, in order to investigate the impact perforation behavior of Carbon Fiber Reinforced Plastics (CFRPs), the ballistic impact tests were conducted on the CFRPs using a one-stage gas gun at impact angles of 0°, 30° and 45° with the speeds varying from 70 to 280 m/s. A high speed camera was used to capture and record the experimental images and data during the impacting process. A simple energy model has been established to evaluate the effect of the impact angle and ballistic limit on the energy dissipated by laminate at velocity close to the ballistic limit. In addition, different failure patterns on the surface of CFRPs were observed under normal and oblique impact by in situ observation. Finally C-Scan and optical microscope were used to detect the delamination and damage beneath the impact point respectively. © 2016 Elsevier Ltd. All rights reserved.

Yin J.,Harbin Institute of Technology | Li D.,Harbin Institute of Technology | Lin Z.,Harbin FRP Institute | Zhang D.,Harbin Institute of Technology | Lu H.,Harbin Institute of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

Through summarizing and analyzing the physical corrosion theories of polymer, a theoretical model is constructed to depict the relationship between relaxation time with temperature, stress and humidity. The correlation between physical corrosion behavior and external factors is predicted from semi-experimental profile. In sequence, the morphology of polymer and fiber was investigated by the scanning electron microscopy (SEM) in comparison with that of nonimmersed samples. The dynamic mechanical thermal analysis (DMTA) methods were used to study the evolution of thermomechanical properties against immersed time. It is found that the glass transition temperature (Tg) and storage modulus were significantly reduced with immersion time increase. Then the hardness, tensile strength and bending strength of GFRP were tested by their corresponding mechanical measurements. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Yang B.,Harbin Engineering University | Zhang J.,Harbin Engineering University | Zhou L.,Hong Kong Polytechnic University | Lu M.,Harbin FRP Institute | And 2 more authors.
Composites Part B: Engineering | Year: 2015

Water absorption and aging behaviors of fiber reinforced polymerized poly (cyclic butylene terephthalate) (GF/pCBT) composites are investigated. We coated nano-silica on glass fiber surface by physical vapor deposition (PVD) method. Subsequently, we immersed pCBT composites reinforced with nano-treated/untreated fibers in 25 °C and 60 °C distilled water until their saturated moisture. We also exposed some specimens in various hydrothermal aging environments. We tested the mechanical performance of these test specimens and found that the mechanical performance of both pCBT cast and GF/pCBT composites reduces obviously after water absorption and hydrothermal aging. However, nano-silica modified fiber reinforced composites have higher remaining strength than GF/pCBT. Scanning electron microscope (SEM) is used to study the microscopic phase and nanoparticle modified mechanism, and better interface characteristic between fibers and matrix is observed. © 2015 Elsevier Ltd. All rights reserved.

Wu H.,Harbin FRP Institute | Hou D.,Harbin FRP Institute | Sun L.,Harbin FRP Institute
Yingyong Lixue Xuebao/Chinese Journal of Applied Mechanics | Year: 2012

It is extremely important that composite damping properties are analyzed and forecasted effectively and the effective control for the structural vibration impact, noise and fatigue failure can be achieved for engineering applications. The cantilever beam method is used for damping testing of glass fiber and carbon fiber composite materials. Meanwhile, the Adams-Bacon and the Ni-Adams method are used to analyze the test results. It is showed that the damping capacity peak of glass fiber and carbon fiber composites is near the fiber orientation of 30° and damping property at the low frequency load is better than that at the high frequency load.

Zhang C.,Harbin Engineering University | Zhang C.,Harbin FRP Institute | Song H.,Harbin Engineering University | Ding H.,Harbin Engineering University | And 4 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

Abstract In this study, three novel thermoplastic poly(benzoxazinone-imide)s (PBEI-I, II, III) were prepared by the dealcoholization of the poly(amide-imide)s (PAMI-I, II, III) with an ester group as the pendent group, which were synthesized by a two-step method via the corresponding polyamic acids (PAA-I, II, III) obtained through the reaction of 4,4′-diamino-6-ethoxycarbonyl benzanilide with 2,3,3′,4′-biphenyltetracarboxylic dianhydride, 2,3,3′,4′-diphenyl ether tetracarboxylic dianhydride and 3,3′,4,4′-benzophenonetetra-carboxylic dianhydride, respectively. The imidization kinetics of the PAAs was investigated by differential scanning calorimetry (DSC) followed by simulation with two different kinetic models, Kissinger and Ozawa. For the three PAAs, the activation energy values determined by the models were in the range of 117.56-141.64 kJ mol-1, the frequency factors were different, and the reaction orders were all approximately one. The value of the activation energy (E a) of PAA-I was lower than those of PAA-II and PAA-III, suggesting that the imidization process of PAA-I occurred more easily than those of PAA-II and PAA-III. This is probably due to the fact of the distorted structures in the α-BPDA as the dianhydride made the molecular packing looser and the energy barrier of the collision reaction among the active groups lower, while the presence of biphenyl linkage has a rigid effect. The thermal performances of the thermoplastic polyimides were then investigated by DSC, infrared spectroscopy and thermogravimetry (TG). The results of the DSC and TG indicated that the thermoplastic polyimides including PAMI-I, II, III and PBEI-I, II, III had good thermal properties. The results of the wide-angle X-ray diffraction showed that all the PAMI-I, II, III poly(amide-imide)s were amorphous. © 2015 Akadémiai Kiadó, Budapest, Hungary.

Zhang C.,Harbin Engineering University | Zhang C.,Harbin FRP Institute | Su G.,Harbin Engineering University | Chen H.,Harbin FRP Institute | And 3 more authors.
Journal of Applied Polymer Science | Year: 2015

Novel polyimides were successfully synthesized through copolymerization of diamine monomers p-phenylenediamine (p-PDA) and 4,4′-diaminodiphenylmethane (MDA) with different proportions and 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) using 4-phenylethynylphthalic anhydride (4-PEPA) as an end-capping agent. The melt rheological properties, thermal properties, and crystallinity of PI oligomers were investigated via rheometer, dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results indicate that melt viscosity and solubility of the PI oligomers were improved, but the glass transition temperature (Tg) and crystallinity decreased with the increasing molar ratio of MDA. PI oligomer 3 with the molar ratio of MDA/p-PDA = 2/1 shows a lower minimum melt viscosity (66 Pa.s) at 313°C and better solubility in aprotic solvents. The corresponding PI-3 exhibits a high glass transition temperature of 406°C and excellent thermal stability. This copolyimide shows good processability and thermal properties, and could become a good candidate of matrix resins for high performance composites in aerospace field. © 2014 Wiley Periodicals, Inc.

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