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Table of Content

    25 April 2012, Volume 40 Issue 4
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    Computer Science & Technology
    SIP Security Scheme of Internet Multimedia Communication
    Hu Jin-long Zhang Ling Xu Yong Ye Zhao
    2012, 40(4):  1-7. 
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    As the traditional software-based SIP security schemes are vulnerable to embezzlement,deception and invasion,a dual authentication framework combined with the trusted computing technology is proposed for endpoint system and user identity. Then,a new SIP security scheme for Internet multimedia communication is presented,which takes advantage of the trusted platform module and the direct anonymous attestation algorithm to design a new registration sub-protocol for improving the security of multimedia communication systems. Moreover,the security of the registration sub-protocol is verified by using the provable security model,and the characteristics of the whole scheme are finally analyzed.

    Super-Resolution Image Reconstruction Based on Manifold Learning and Gradient Constraint
    Liao Xiu-xiu Han Guo-qiang Wo Yan Huang Han-quan Li Zhan
    2012, 40(4):  8-15. 
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    Proposed in this paper is a novel super-resolution reconstruction algorithm of single-frame images,which integrates the improved super-resolution reconstruction based on manifold learning with the regularized reconstruction based on gradient constraint. In this algorithm,a new feature extraction method,which combines the two feature vectors of the normalized luminance and the detail sub-band coefficient of stationary wavelet transform,is put forward for the super-resolution reconstruction based on manifold learning,and is used to improve the reconstruction performance. Then,a regularized reconstruction based on gradient constraint is implemented to obtain the final high-resolution image,with the learned high-resolution image and its gradient respectively as the initial estimate and the target gradient field. As compared with some existing algorithms,the proposed algorithm is of better reconstruction performance in terms of both visual effect and objective evaluation.

    Image Tampering Detection Algorithm Based on Double Detection Mechanisms
    Hu Yong-jian Zhang Shang-fan Liu Bei-bei Tan Li-ling
    2012, 40(4):  16-22. 
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    As the classical correlation-based image tampering detection algorithms cannot avoid false alarm and misdetection,a novel algorithm based on double detection mechanisms is proposed. In this algorithm,first,tampered image blocks under suspicion are picked out according to the correlation between the camera fingerprint in each region of the detected image and that for reference. Then,image features are extracted from each suspicious image block and are sent to a trained SVM ( Support Vector Machine) to construct an image features-based SVM classifier for distinguishing the mis-detected blocks from the real tampered ones. Experimental results demonstrate that the proposed method outperforms the classical one only based on the correlation of camera fingerprints.

    Accurate and Fast Harmonic Transform of Polar Coordinates
    Wo Yan Xu Jiao
    2012, 40(4):  23-29. 
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    This paper deals with the extension of the computation method of Zernike moments in polar coordinates to the computation of PHT moments in Cartesian coordinates. In the investigation,polar coordinates are designed and modulated for the computation of PHT moments,which can eliminate the geometric error and the integral approximate error of the computation in Cartesian coordinates. And,during the calculation of the kernel coefficients of PHT,the symmetry and the inquiry table of trigonometric function are used to reduce the computational complexity. Thus,the computation is accelerated and the iterative cumulative error is eliminated. The proposed fast PHT algorithm based on polar coordinates is finally verified by experiments and is compared with the existing one based on Cartesian coordinates. Experimental results show that the proposed algorithm is superior to the PHT algorithm based on Cartesian coordinates in terms of reconstruction accuracy,rotation scale invariance and calculation speed.

    Routing Algorithm for Wireless Sensor Networks Based on Borel Metacyclic Topology
    Li lan Xiao Wen-jun Wei Wen-hong
    2012, 40(4):  30-36. 
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    In this paper,a novel five-regular Borel metacyclic graph with symmetric structure,small diameter and high clustering coefficient is created by using the Borel matrix group and the semi-direct product method in the group theory. Then,by embedding wireless sensor nodes in this metacyclic graph,a structured data-centric storage and routing algorithm is designed,which is further compared with the CSN based on Chord and the VRR. The results show that the proposed algorithm is superior to some existing algorithms in terms of routing query length,routing table size,end-to-end delay and energy dissipation,which benefits the prolonging of the life of sensor network nodes.

    Cooperation-Guaranteeing Mechanism Based on Altruism Punishment in Mobile Peer-to-Peer Networks
    Liu Jia-qi Chen Zhi-gang Li Deng Liu Hui
    2012, 40(4):  37-42. 
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    In this paper,a cooperation-guaranteeing mechanism based on altruism punishment in mobile peer-topeer networks is presented,which takes into consideration the existence of altruism punishment widely observed in a lot of experiments in behavioral economics. In this mechanism,it is supposed that some nodes in the system have the predisposition to punish the selfish nodes with non-cooperation behaviors,even though they may receive lower payoffs or nothing. The selfish nodes are thereby restricted and their non-cooperation probability is reduced. Theoretical analysis and numerical simulation show that the proposed mechanism is reasonable and effective in reducing the number of selfish nodes and improving the cooperation.

    Design of Dynamic Virtual Fixture for Robotic Teleoperation with Early Warning Function
    Du Guang-long Zhang Ping
    2012, 40(4):  43-48,63. 
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    In order to remedy the disadvantages of the existing virtual fixtures,namely the inflexibility of design,the splicing roughness of geometric model and the insufficiency of early warning,a dynamic generation algorithm of the security pipe is proposed based on the finite element,and the dynamic expansion algorithm of the security extension pipe as well as the dynamic generation algorithm of the early warning pipe is also presented. Then,a case study is carried out to verify the proposed algorithm. The results show that the designed security extension pipe can be extended to avoid dynamic obstacles and can alarm when the robot runs across the security extension pipe,and that the designed early warning pipe can dynamically shrink according to the robot’s jitter and can alarm when the robot runs across the early warning pipe. It is thus concluded that the proposed dynamic generation algorithm helps to improve the safety and accuracy of robotic teleoperation because it can generate virtual fixtures with early warning function according to the paths in real time.

    GBLHT: a GPU-Accelerated Linear Hash Table with Batch Insertion
    Huang Yu-long Xi Jian-qing Zhang Ping-jian Fang Xiao-lin Liu Yong
    2012, 40(4):  49-56. 
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    In order to improve the insertion performance of linear Hash table known as an effective index structure,the existing insertion methods are analyzed,and a linear Hash table GBLHT with batch records insertion,which is combined with the CUDA parallel programming model,is designed and implemented. With the help of the atomic function atomicAdd,GBLHT takes full advantage of the high parallel throughput of graphic processing unit ( GPU) to implement the lock-free batch insertion of massive records. Some experiments are then carried out to compare the insertion performances of the traditional serial insertion method,the CPU-based batch insertion method and GBLHT. The results show that,under various parameter conditions,the insertion performance of GBLHT is 7~14 times higher than that of the traditional serial method,and is 3~6 times higher than that of the CPU-based batch insertion method with four threads.

    Construction Algorithm of ranking Model Based on Non-Convex Upper Bound
    Cheng Fan Wang Xu-fa Li Long-shu
    2012, 40(4):  57-63. 
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    As the existing ranking algorithms all construct models by minimizing the convex upper bound of the original objective functions,the constructed models are imprecise. In order to solve this problem,a ranking algorithm based on non-convex upper bound is proposed. In this algorithm,first,a framework based on multi-class support vector machine ( SVM) is constructed and an objective function directly optimizing the NDCG ( Normalized Discounted Cumulative Gain) is defined. Then,a tighter non-convex upper bound is designed to approximate the original objective function. Moreover,a concave-convex procedure is carried out and the cutting plane algorithm is used to remedy the non-convex and non-smooth characteristics of the objective function. The proposed algorithm is finally verified on the benchmark datasets. The results show that,as compared with the existing ranking algorithms based on convex upper bound,the proposed algorithm is more effective in constructing models with high accuracy and strong stability.

    A Two-Domain No-Reference Video Quality Assessment Algorithm
    Lin Xiang-yu Chen Yao-wu
    2012, 40(4):  64-70,78. 
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    In order to improve the accuracy and reduce the computational complexity of video quality assessment,a two-domain no-reference video quality assessment algorithm is proposed. In this algorithm,first,encoding information is extracted from the bitstream and video similarity is calculated according to the complexity of video contents in the compressed domain. Then,by taking into consideration the characteristics of human visual system,the video distortion is calculated by measuring the influence of blockiness and the blur artifacts in the pixel domain. Thus,the video quality is assessed according to the video similarity and the video distortion. The proposed algorithm is finally tested on the LIVE Video Quality Database. The results show that the proposed algorithm,which possess a prediction accuracy and a monotonicity respectively up to 0.8013 and 0.7861,is better than the existing ten video quality assessment techniques,and that it meets the requirements of real-time application because it is of low computational complexity.

    Parallel Optimization of Three-Dimension Particle Simulation Based on Mixed MPI /OPENMP Programming
    Yan Xiao-yang Zhang Wei-wen Bu She-hui Deng Hui-fang
    2012, 40(4):  71-78. 
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    In order to remedy the shortcomings of the parallel MPI program and the parallel OPENMP program,a mixed parallel programming combining MPI and OPENMP is implemented. Then,the parallel processes of the MPI program,the OPENMP program and the mixed parallel MPI /OPENMP programming are respectively analyzed through experiments. The results show that the mixed parallel MPI /OPENMP programming greatly reduces the communication traffic,achieves an efficiency and a speedup rate higher than those of the parallel MPI program,and avoids the performance degradation of parallel MPI program due to the load imbalance caused by uneven particle distribution. Thus,more nodes in the cluster can be used to perform a computation and the communication delay can be successfully decreased. Moreover,the mixed parallel programming significantly enlarges the simulation scale because it overcomes the dependency of parallel OPENMP program on the processing capacity and the storage space of a single computer.

    Materials Science & Technology
    Effect of Cementitious Material Content on Properties of Fresh Self-Compacting Concrete
    Li Fang-xian Wei Jiang-xiong Wang Hui-cheng Wang Jing-ping Pei Xin-yi Yu Qi-jun
    2012, 40(4):  79-84. 
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    Self-compacting concrete with a cementitious material content varying from 460 to 550 kg /m3 was prepared,and the workability of the concrete was tested via the normal method. Then,the air void parameters of the self-compacting concrete mixture and the rheological parameters of the mortar with gravels being filtered out were tested by using an air void analyzer and a rotary rheometer,and the temperature-rising process of the concrete was analyzed by using an adiabatic temperature-rising analyzer. The results show that the self-compacting concrete is of better flowability,passing ability,segregation resistance as well as better pore structure when the cementitious material content varies from 480 to 500 kg /m3 ,while it is of poor pore structure when the content reaches 550 kg /m3 ;and that,with the increase of the cementitious material content,both the plastic viscosity and the yield stress of the concrete increase,the stability of thixotropic structure degrades,and the maximum adiabatic temperature rising as well as the peak of temperature rising rate increases.

    Influence of Cementitious Material Composition on Durability of Reinforced Concrete
    Fan Zhi-hong Li Peng-ping Su Da-gen Wang Sheng-nian
    2012, 40(4):  85-89,94. 
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    This paper deals with the influences of cementitious material composition on the durability of reinforced concrete with extravasated chloride via electrochemical impedance spectroscopy and MIP test. The results show that,with the increases of fly ash or slag content in the cementitious material,the durability,the resistivity and the charge transfer resistance of reinforced concrete all increase first and then decrease,while the corrosion rate of steel varies in an opposite trend; and that the chloride threshold concentration decreases with the increase of dissolved oxygen content and with the decrease of Ca(OH)2 content around the steel. Moreover,it is found that,when cement is partially substituted with fly ash or slag,the density of the concrete increases,which results in the increase of charge transfer resistance,the improvement of stability of the passive film,the decrease of Ca(OH)2 content,and,finally,the decrease of the chloride threshold concentration.

    Effect of Cement Calcination with Municipal Sewage Sludge on Nitrogen Oxide Emission
    Zhang Ling-hui Su Da-gen
    2012, 40(4):  90-94. 
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    In this paper,the effect of cement calcination with municipal sewage sludge on the nitrogen oxide( NOx ) emission was investigated by means of XPS,DSC-TG and NOx monitoring. The results indicate that ( 1) two distinct exothermic peaks appear during the combustion of sewage sludge of which the volatiles and nitrogen contents are higher than those of coal; ( 2) the fuel-NOx produced by the combustion of sewage sludge in oxidizing atmosphere at 900℃ is less than that produced by the combustion of coal under the same conditions; ( 3) cement raw material accelerates the emission of fuel-NOx by the combustion of sewage sludge or coal in oxidizing atmosphere at 900 ℃; ( 3) the addition of sewage sludge in coal helps to reduce the emission of fuel-NOx; ( 4) dry sludge
    with equal amount but higher moisture content helps to produce less fuel-NOx; and ( 5) comprehensively speaking,the appropriate moisture content of sewage sludge is about 10%.

    Preparation and Formation Mechanism of Narrow-Dispersed Poly( Aminopropyl /Phenylsilsesquioxane) Microspheres
    Liu Shu-mei Sun Zhi-song Zhang Yu Zhang Li-ping Zhao Jian-qing
    2012, 40(4):  95-100,106. 
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    Narrow-dispersed poly( aminopropyl /phenylsilsesquioxane) ( PAPSQ) microspheres were prepared via the hydrolytic cocondensation of γ-aminopropyltriethoxysilane ( APS) and phenyltriethoxysilane ( PTES) under the action of alkali catalysts,and the effects of the APS-to-PTES molar ratio,the water-to-silicon molar ratio,the cosolvent type,the tetramethylammonium hydroxide ( TMAOH) concentration and the total monomer concentration on the morphology and size of PAPSQ microspheres were explored by using a scanning electron microscope and a particle size analyzer. Moreover,the formation mechanism of the microspheres under different reaction conditions was investigated. The results indicate that ( 1) when ethanol is used as the co-solvent,narrow-dispersed microspheres with a diameter ranging from 0.7 to 1.0 μm are obtained at an APS-to-PTES molar ratio of 1 /4,a water-to-silicon molar ratio of 50,a TMAOH concentration of 0.025mol /L and a total monomer concentration of 0.25mol /L; ( 2) with ammonia as the catalyst and with isopropanol as the co-solvent,microspheres with large size and broad distribution can be obtained; ( 3) only partial spherical particles may form at lower water-to-silicon molar ratio and TMAOH concentration; and ( 4) no spherical particles can form if the total monomer concentration is too high.

    Reinforcement of Natural Rubber with Nanocrystalline Cellulose as a Substitution for Carbon Black
    Gu Ju Lin Lu Luo Yuan-fang Jia De-min
    2012, 40(4):  101-106. 
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    Natural rubber /nanocrystalline cellulose /carbon black ( NR/NCC /CB) composite was prepared by using NCC as a partial substitution for CB,and the effect of NCC on the properties of NR/CB composite was investigated. The results show that ( 1) with the addition of NCC,the elongation at break of NR/CB composite increases to more than 500%,while the permanent set decreases to less than 30%; ( 2) both the tensile strength and the tear strength of NR/NCC /CB composite are similar or superior to those of NR/CB composite,while the hardness keeps unchanged; ( 3) the abrasion resistance of the composite keeps well when the NCC substitution rate for CB ranges from 5 to 20 phr; ( 4) the flex cracking resistance of the composite improves when the NCC substitution rate is less than 15 phr; ( 5) the addition of NCC improves the thermal oxidative aging property and reduces the heat buildup due to dynamic compression; and ( 6) the temperature of heat buildup reaches its minimum value of 13.0℃ when the NCC substitution rate is 10 phr.

    Constitutive Equation Describing Creep Ageing of 2124 Aluminum Alloy
    Zhan Li-hua Li Yan-guang Huang Ming-hui Zhang Meng
    2012, 40(4):  107-111. 
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    Uniaxial tensile creep ageing experiments of 2124 aluminum alloy specimens were carried out under the stress of 200,225 and 250MPa at 185℃. It is found that,at a constant temperature,the creep behaviors become more distinct with the increase of experimental stress and ageing time. Then,according to the creep theory and the creep curves,a constitutive equation was established and was used to describe the creep behaviors of 2124 aluminum alloy at 185℃ under different stress conditions. Moreover,the constants of the constitutive equation were determined with SPSS and Origin. By comparing the experimental data with the fitting curves,it is concluded that the proposed constitutive equation well describes the creep behaviors of 2124 aluminum alloy at 185 ℃ under different stress conditions.

    Architecture & Civil Engineering
    Frequency Domain Analysis for Wind-Induced Vibration Response of Long-Span Cable Dome Structures
    Wei De-min Xu Mu Li Di
    2012, 40(4):  112-117. 
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    In this paper,two finite element models are established to respectively analyze the wind-induced vibration response of cable dome structures with and without top cable-membrane. Then,the structural mode and the wind-induced vibration response in the frequency domain are analyzed through an engineering example,and the standard deviation of the displacement responses to the fluctuation wind load is obtained. The results show that ( 1) the suitable number of dominant modes increases with the enlargement of the span; ( 2) for the cable-dome-like structures with a span longer than 100m,the number of dominant modes is suggested to be more than 450; ( 3) the standard deviations of the node displacements of both the cables and the poling in CSM are less than those in CS; ( 4) the envload affection of the membrane can not be ignored in CSM; ( 5) in CSM,the structural pulse wind energy is mostly dissipated by the membrane; and ( 6) top cable-membrane greatly affects the wind-induced vibration response of long-span cable dome structures.

    Rapid Algorithm and Its Application of Wind-Induced Vibration Response of Super High-Rise Building Under the Control of Multiple Tuned Mass Dampers
    Li Xiao-kang Xie Zhuang-ning Wang Zhan
    2012, 40(4):  118-124. 
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    Proposed in this paper is a rapid algorithm based on the harmonic excitation method,which is used to calculate the wind-induced vibration ( WIV) of large-scale complex structures under the control of multiple tuned mass dampers ( MTMD) according to the time-historic wind loads obtained in the rigid-model wind tunnel test. Then,by taking the Shenzhen Kingkey Finance Tower ( KFT) with a height of 439 m as a research objective,the WIV response of KFT under the control of single tuned mass damper ( STMD) is analyzed,and the effects of MTMD configuration as well as the natural frequency,damping ratio and mass of STMD on the WIV response are compared and discussed. The results show that ( 1) the proposed rapid algorithm is accurate and effective in calculating the WIV; ( 2) a STMD installed at the top floor can effectively mitigate the WIV of KFT; and ( 3) though STMD is more effective than MTMD with the same total TMD mass,MTMD can still reduce the peak acceleration of WIV response at the top of the building by about 30%.

    Structural Reliability Analysis Based on Stochastic Response Surface Method and Elastic Modulus Reduction Method
    Yu Bo Yang Xian-feng Yang Lü-feng
    2012, 40(4):  125-130,168. 
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    Proposed in this paper is a reliability analysis method based on the stochastic ultimate bearing capacity,which combines the stochastic response surface method(SRSM)with the elastic modulus reduction method(EM-RM). In the investigation,first,based on the limit analysis theory and the generalized yield criterion,an EMRM is developed to determine the ultimate bearing capacity. Then,an improved SRSM for stochastic response analysis is proposed based on the stepwise regression analysis and the linear independent criterion. Finally,a novel reliability analysis method is presented based on the expansion of the stochastic ultimate bearing capacity determ ined by the SRSM and the EMRM. Numerical example shows that the proposed method is of high accuracy and efficiency for structural reliability analysis because it helps to directly obtain the expansion of the stochastic uhimate bearing ca-pacity and the structural perform ance function.

    Pseudo-Dynamic Test and Analysis of Single-Storey Full-Scale Masonry Structure
    Tan Xiao-jing Wu Bin
    2012, 40(4):  131-137. 
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    A full-scale model of a one-bay masonry structure with ring beams and tie columns was established. Then,the seismic response of a single-storey ten-bay masonry structure was simulated by pseudo-dynamic tests,and the failure process of the specimen under loads was observed. Moreover,a seismic response analysis program for the test model was compiled to calculate the structural displacement response,and the results were compared with the test ones. Finally,the theoretical bearing capacity of the test structure was calculated by using different analytic equations,and the results were also compared with the test ones. It is found that ( 1) the structure as a prototype of the test model with ring beams and tie columns,which can withstand the seismic excitation with a peak ground acceleration of 1.6g,exhibits satisfactory seismic behavior; ( 2) the maximum bearing capacity of the structure with ring beams and tie columns increases by 20%~50%; and ( 3) the details of seismic design are helpful in improving the seismic behavior of masonry structures.

    Influence of Temperature on Modal Parameters of Bridge
    Li Xiao-nian Chen Ai-rong Ma Ru-jin
    2012, 40(4):  138-143. 
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    In this paper,a theoretical formula describing the temperature effect on the frequency of simply-supported beam is deduced. Thenby taking a single-pylon cable-stayed bridge with curved composite beam as the object,the temperature response and the effect on the frequency are analyzed,and a finite element method is proposed to quantify the effect of ambient temperature on the frequency of complex structures. The results show that ( 1) ambient temperature influences the modal frequency of the bridge structure mainly in three ways,namely,changing the structural size,producing internal force in the statically indeterminate structure and changing the mechanical properties of the structural material; ( 2) the influence of structure size change on the modal frequency can be neglected; and ( 3) the influence degree of ambient temperature on the modal frequency mainly depends on the structure form,the material,the section size and the internal force state. Moreover,case study results indicate that ( 1) different temperature modes have different influences on the deformation and the internal force of the structure; ( 2) the influence of uniform temperature on the modal frequency of cable-stayed bridge is mainly due to the change
    of elastic modulus,while the influence of girder temperature gradient is mainly due to the change of internal force; and ( 3) neither the cable temperature difference nor the pylon temperature gradient has any significant influence on the modal frequency.

    Energy-Saving Optimization of Air Conditioning Terminal Device Based on Numerical Simulation
    Yan jun-wei Liu yang Zhou xuan Kang ying-zi
    2012, 40(4):  144-149. 
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    In this paper,first,a physical model of an office was built. Then,based on the indoor zero equation turbulence model,a numerical simulation of the air distribution in the modeled office with air conditioning terminal device was carried out with AIRPAK3.0. Moreover,the effects of air supply temperature and velocity on the thermal comfort were analyzed,and the air supply parameters at the typical moments in one day were optimized,with the results being finally compared with the actual operation data. It is found that the air conditioning terminal device is of great energy-saving potential,and that,after the optimization of operation parameters,the theoretical cooling capacity of the terminal device in one day averagely reduces by 17%.

    Mechanics
    Hydrodynamic Characteristics of Tethered Underwater Robot Under Control Manipulations
    Wu Jia-ming Cui Yin Deng Wei Wu Li Ma Zhi-quan
    2012, 40(4):  150-157. 
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    A controller based on an integrated hydrodynamic model of the tethered underwater robot is constructed with the help of FNN ( Fuzzy Neural Network) algorithm and is used to control the trajectory and attitude of the robot in multiple degrees of freedom. Then,in order to remedy the disadvantages of the traditional method of analyzing propeller propulsion,a new method combining the theory of neural network and the computational fluid dynamics technique is proposed for the conversion between the propulsion and the rotating speed. Moreover,an integrated control system,which consists of a FNN controller,a robotic hydrodynamic model and a conversion module of propulsion and rotating speed,is presented for the tethered underwater robot. Finally,the hydrodynamic characteristics of the robot are globally analyzed and calculated by taking into consideration the interaction among different parts of the robot. Numerical simulation results indicate that the proposed system effectively controls the trajectory and attitude of the tethered underwater robot,and that it helps to globally calculate the hydrodynamic response of the underwater robot under corresponding control action.

    Buckling of FGM Cylindrical Shells Under Combined Axial Compression and Bending Loads
    Huang Huai-Wei Han Qiang Wei De-Min
    2012, 40(4):  158-161. 
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    By combining theoretical analysis with numerical simulation,the buckling behaviors of FGM ( Functionally Graded Material) cylindrical shells under combined axial compression and bending loads are investigated. Then,on the basis of the classical Donnell shell theory,a buckling governing equation of the shells is deduced,and the critical condition for the buckling is determined via an eigenvalue analysis. Theoretically calculated results reveal that the critical load of bending buckling linearly decreases with the increase of axial compression,but increases with the content of ceramic constituent in FGM. The theoretical results are finally compared with the numerical ones obtained by ABAQUS simulation,with a good accordance being found,which means that the proposed theory is reliable.

    Numerical Analysis of Stress Intensity Factor of Surface Crack in Steel Plate Strengthened with CFL Under Bending Load
    Zhang Shu-kuan Huang Pei-yan Zhao Chuan-yu
    2012, 40(4):  162-168. 
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    With the help of ANSYS,a finite element model is proposed to calculate the stress intensity factor ( SIF) of semi-elliptical 3D surface crack in the steel plate strengthened with carbon fiber laminate ( CFL) . Then,based on this model,the effects of CFL thickness,crack shape ratio and crack area on the SIF are analyzed for the strengthened steel plate under bending load. The results show that ( 1) CFL strengthening greatly decreases the SIF of surface crack in the steel structure,with a rate reducing with the increase in CFL thickness; ( 2) larger surface crack is more helpful in decreasing the SIF and enhancing the strengthening; and ( 3) for the steel plate with shallow and long cracks,a front strengthening with CFL may work even better.

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