Table of Content

25 November 2015, Volume 43 Issue 11

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Food Science & Technology

Effects of Heat and Cold Pressing Processes on Flavor Compounds of Linseed Oil and Corresponding Analysis of Key Aroma Compounds

Liu Guo-qin Fang Zhao-xi Li Qi

2015, 43(11):  1-7.  doi:10.3969/j.issn.1000-565X.2015.11.001

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Two kinds of linseed oil were prepared through heat and cold pressing processes，and the volatile compounds from the prepared linseed oil were detected by means of the head space-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS)． Then，the contents of such volatile compounds as alcohols，aldehydes and ketones from the two kinds of linseed oil were discussed，and their content changes were also analyzed． Moreover，the odor activity value (OAV) was employed to determine the key aroma compounds in the two kinds of linseed oil． The results show that (1) the flavor compounds in both heat-pressed oil and cold-pressed one mainly include alcohols，aldehydes，ketones，furans，dimethyl sulfide，et al; (2) the flavor of the linseed oil can be attributed to the key aroma compounds，which are in the order of dimethyl sulfide ＞ hexanal ＞ propanal ＞2-butanol ＞ 1-hexanol ＞ 3-methyl-1-butanol ＞ 3-pentyl alcohol ＞ 2-methyl-propanol ＞ 2-methyl-1-butanol;(3) among these compounds，dimethyl sulfide and aldehydes make greater contribution to the overall flavor of the linseed oil，alcohols make a minor contribution to the overall flavor，but ketones and furans produce no actual effect on the overall flavor due to their greater threshold and smaller OAVs; and (4) the OAVs of dimethyl sulfide and aldehydes in the heat-pressed linseed oil are much greater than those in the cold-pressed samples，so the heat-pressed linseed oil has a stronger “grassy”smelling odor．


Separation，Identification and Antioxidant Activity of Glycoproteins from Millettia Speciosa Champ．

Zhao Qiang-zhong Feng Meng-ying Lin Lian-zhu Zhao Mou-ming

2015, 43(11):  8-15.  doi:10.3969/j.issn.1000-565X.2015.11.002

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In order to understand well the structural characteristics，physical and chemical properties and biologi-cal activities of glycoprotein from Millettia Speciosa Champ． (MSCG)，MSCG was purified by means of ultrafiltra-tion，chromatography Sephadex G-75 and ODS according to its molecular mass distribution，and thus two purified fractions MSCG-1 and MSCG-2 were obtained． Then，the structures of the two fractions were identified by means of HPLC，GC，GC-MS and FT-IＲ． The results show that (1) the molecular masses of MSCG-1 and MSCG-2 are 62. 00 ku and 1. 94 ku respectively; (2) MSCG-1 contains 50. 22% protein and 38. 07% sugar，and it is mainly composed of → 4，6)-Galp-(1 → and Araf-(1 → ; (3) MSCG-2 contains 69. 37% protein and 6. 70% sugar，and its main chain is composed of → 6)-Glcp-(1 → and has a high branch degree; (4) MSCG-1 and MSCG-2 both con-tain O-link bonds; (5) for the amino acid which may be of antioxidant activities，its content in MSCG-2 is 31. 3% higher than that in MSCG-1; (6) the oxygen radical absorbance capacities (ORAC) of MSCG-1 and MSCG-2 are (56. 10 ±18. 49) and (1077. 19 ± 60. 82) μmol/g; and (7) the antioxidant activity of MSCG-2 is significantly higher than those of MSCG and MSCG-1，which means that the molecular composition，molecular mass and struc-tural characteristics of glycoprotein determine their antioxidant activities．


Physicochemical Properties of Covalent Conjugates Prepared in Macromolecular Crowding Environment or via Dry-Heating Method

Qi Jun-ru Weng Jing-yi Feng Ji-lu Liu Qian-ru Yang Xiao-quan

2015, 43(11):  16-22.  doi:10.3969/j.issn.1000-565X.2015.11.003

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Two kinds of β-conglycinin-dextran conjugates were prepared respectively in the macromolecular crowding environment or via the dry-heating method，and then a comparison was made in their physicochemical property． On the basis of the solubility of glycation products at the isoelectric point of β-conglycinin (pH =4. 8) or under the neutral condition (pH =6. 5)，the products were separated into two components，and then a discussion was conducted about the graft degree，secondary structure，internal fluorescence and turbidity of the two components．The results show that (1) β-conglycinin in the macromolecular crowding and liquid phase environment is hydrolyzed to a certain degree，with small peptide chains being produced，which is beneficial to the covalent access of polysaccharide; (2) MC48 obtained at pH4. 8 in the macromolecular crowding environment，is mainly the glycation product of high graft degree，while MC65 obtained at pH6. 5 in the macromolecular crowding environment，contains the glycation products of both low and uneven graft degree; and (3) DH48 and DH65 obtained respectively at pH4. 8 and pH6. 5 via the dry-heating method，are of low graft degree，and their difference is less significant than that in the macromolecular crowding environment． Moreover，it is found from SDA-PAGE，CD and intrinsic fluorescence emission spectra that there exists a significant difference in physicochemical property between MC48 and MC65，while an insignificant difference between DH48 and DH65．


Investigation into Preparation Technology of Epoxidized Soybean Oil via Phase-Transfer Catalysis

Cheng Wei-wei Liu Guo-qin Liu Xin-qi Wang Xue-de Lu Xiao-zhu

2015, 43(11):  23-29.  doi:10.3969/j.issn.1000-565X.2015.11.004

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At present，the industrial application of per-acid to the production of epoxidized soybean oil ( ESO) can lead to serious pollution，so it is necessary to explore the preparation technologies of green epxidized soybean oil． In the investigation，by taking H2O2 as the oxygen source，a mathematical model on the basis of the response surface methodology was constructed to optimize the preparation technology of ESO obtained through phase-transfer catalysis． Then，the prepared ESO was characterized by means of FT-IＲ，and its physical and chemical property and thermal stability were also analyzed． The results show that，under the optimal conditions，namely，a mass ratio of H2O2，catalyst，PEG and soybean oil of 87∶29∶30∶100，a temperature of 55℃ and a reaction time of 3. 5 h， the predicated epoxy value of ESO，which is 6. 48% ，is close to the tested value of 6. 40% ，which means that the proposed model on the basis of the response surface methodology can be used to guide the preparation of ESO． The prepared ESO with mild reaction conditions and short reaction time meets the national industry standard，and it is of a better thermal stability，specifically，its epoxy value decreases only by 0. 48% with a processing time of 3. 0 h at 177℃ ． The results of IＲ confirm that the unsaturated double bonds are converted into the epoxy bonds after the selective oxidation of soybean oil．

Computer Science & Technology

A Degree Sequence-Based Complex Network Model and Its Ｒouting Strategy Analysis

Xiong Yun-yan Xiao Wen-jun Mao Yi-jun Lai Zheng-wen Han Dong

2015, 43(11):  30-34.  doi:10.3969/j.issn.1000-565X.2015.11.005

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By analyzing the length l of the vertex-degree sequence { k1，k2，…，kl} ( 1≤k1 ＜ k2 ＜ … ＜ kl ) of the complex network with general degree distribution，the general characteristic of the length of the vertex-degree sequence is obtained in this paper，which is that l is the order of log2N ( N is the number of network nodes) ． Meanwhile，on the basis of the real complex network datasets and the BA model datasets，the empirical analysis is performed，and the results also show this characteristic． Then，the efficiency in building routing tables in large-scale complex networks is analyzed，and many complex networks on the basis of vertex-degree sequence are constructed． Finally，through simulation experiments in complex networks，the performance of the routing strategy on the basis of the breadth first search algorithm ( BFS) is compared with that on the basis of the max degree algorithm ( MD) ． It is found that the latter is better than the former

A Transition-Based Word Segmentation Model on Microblog with Text Normalization

Qian Tao Ji Dong-hong Dai Wen-hua

2015, 43(11):  35-46,53.  doi:10.3969/j.issn.1000-565X.2015.11.006

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In order to harness the strong horsepower of multi-core processors and meet the demand of high parallelism，a new parallel conjugate gradient algorithm is proposed，which focuses on solving the linear equations of large-scale sparse matrices． For the GPU coprocessors，the memory hierarchy of GPU is effectively utilized，optimization methods，such as thread and matrix mappings，data merging and data multiplexing，are adopted，and an effective thread scheduling is conducted to hide the high latency of accessing the global memory of GPU． For Xeon Phi processors，the computation of high parallelism is effectively utilized to optimize data communication and transmission，data dependence reduction，vectorization and asynchronous computation，and effective thread scheduling is also conducted to hide the high latency of accessing global memory of GPU． Finally，the proposed algorithm is proved to be feasible and correct by tests on GPU and Xeon Phi，and its parallel efficiencies in two different ways are compared． It is found that the proposed algorithm on GPU has a better acceleration effect than itself on Xeon Phi．


A Transition-Based Word Segmentation Model on Microblog with Text Normalization

Qian Tao Ji Dong-hong Dai Wen-hua

2015, 43(11):  47-53.  doi:10.3969/j.issn.1000-565X.2015.11.007

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Traditional word segmentation methods fail to achieve good performance on microblog texts，which can
be attributed to the lack of annotated corpora and the existence of a large number of informal words． In order to solve the two kinds of problems，a joint model of word segmentation and text normalization is proposed． In this model，on the basis of the transition-based word segmentation，the texts are normalized by extending transition actions and then the words are segmented on the normalized texts． By experiments，the proposed model is trained on both a large number of annotated standard corpora and a small number of microblog corpora． The results show that the proposed model is of better domain adaptability，and it reduces the error rate of word segmentation by 10. 35% in comparison with traditional methods．


Adaptive Bilateral Filter for Mesh Denoising

Jiang Liang-liang Yang Fu-zheng Ren Guang-liang

2015, 43(11):  54-60,74.  doi:10.3969/j.issn.1000-565X.2015.11.008

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In this paper，an adaptive bilateral filter is proposed to remove noises in 3D mesh models． Firstly，the feature detection of 3D mesh models is performed on the basis of the volume integral invariant，and the local feature strength is estimated． Then，the proposed filter adaptively adjusts the denoising parameters in the bilateral filter according to the local feature strength． Through the adaptive optimization of parameters，the proposed filter provides targeted denoising strategies for the regions with different feature strength，thus further improving the denoising performance． Experimental results reveal that，in comparison with common bilateral filters，the proposed adaptive bilateral filter achieves a superior performance in preserving the sharp features of 3D mesh models during the denoising，and the objective distance measure between the denoised mesh model and the original model is averagely reduced by 0. 0332．

Materials Science & Technology

Multi-Objective Optimization of Ｒoll Forgings of Coupler Yoke Based on MBC Toolbox

Zhou Jie Tao Ya-ping Zhang Jian-sheng Shao Chang-wei Luo Yan

2015, 43(11):  61-66.  doi:10.3969/j.issn.1000-565X.2015.11.009

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In order to reveal the impact of both process parameters and blank size on the length of the roll forging of coupler yoke，the maximum torque of roller and the filling rate of coupler yoke forgings，a mathematical model is constructed by taking a 13B coupler yoke as the research objective and on the basis of the model-based calibration ( MBC) in the software Matlab． In this model，the length of blank is set as local variable，roller clearance，friction coefficient，blank temperature and roller speed are set as global variables，and length of roll forgings，maximum torque of roller and filling rate of coupler yoke forgings are set as the objective function． Then，finite element simulation is conducted，and objective function is optimized through the CAGE toolbox in the MBC． Thus，both optimized look-up table and optimal parameter combination of forging forming are obtained，in which the blank size is 160 mm × 865 mm with a roller clearance of 3 mm，a friction coefficient of 0. 67，a blank temperature of 1 180 ℃ and a roller speed of 15 r/min． Finally，the proposed method is proved to be feasible through the contrast of finite element simulation results and actual production． Therefore，this study offers an effective technology to control the length of precision roll forgings and the filling rate of coupler yoke forgings

Numerical Simulation on Flow and Heat Transfer Behaviours During Planar Flow Casting of Amorphous Alloy Fe₇₈Si₉B₁₃ Ribbon

Sun Hai-bo Li Lie-jun

2015, 43(11):  67-74.  doi:10.3969/j.issn.1000-565X.2015.11.010

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On the basis of two models，namely，the developed coupled model of two-dimensional transient heat transfer and multiphase flow and the model of three-dimensional transient heat transfer of single-roller crystallizers， the fluid flow and heat transfer behaviors during the puddle forming precess of the planar flow casting ( PFC) of Fe78 Si9B13 as well as the heat transfer characteristics of rollers are investigated according to the production data． The results show that ( 1) under a given casting condition，the upstream and downstream meniscuses of the formed puddle are respectively in a crescent shape and in a slope shape with ripple; ( 2) the time for the crystallizer to reach a quasi-thermal equilibrium state is 20 s; ( 3) the impact of high temperature melts on the crystallizer causes an melt impact region of a depth of 0. 0004 m to form，where the maximum temperature in the center of crystallizer surface is about 513. 5K; and ( 4) in comparison with the radial thermal expansion，the circumferential thermal expansion of crystallizer plays a more important role in the actual total expansion，which accounts for 96% ．

Effect of Rolling Deformation on Microstructure and Mechanical of Al-5Zn-3Mg-1Cu Alloy

Li Dong-feng Zhang Xin-ming Liu Sheng-dan Yin Bang-wen Lei Yue

2015, 43(11):  75-80.  doi:10.3969/j.issn.1000-565X.2015.11.011

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Tensile test at room temperature and Kahn tear test were conducted to investigate the evolution of the microstructure and mechanical properties of Al-5Zn-3Mg-1Cu thick plate during the hot rolling by means of OM and TEM． The results show that (1) during the hot rolling of the aluminum alloy，both the deformation and the fraction of recrystallization increase respectively from 56% and 0. 49% to 91% and 43. 30%，while the grain size decreases from 83μm to below 10μm; (2) meanwhile，the tensile strength and yield strength of the aluminum alloy increase respectively from 542. 3 and 520. 0MPa to 593. 4 and 564. 9MPa，and the elongation increases from about 8. 0% to 11. 2%; and (3) as the deformation increases，the tear strength (TS) and UIE of the aluminum alloy tend to increase．


Thickness Uniformity Control of Sputtered Film Based on Roll-to-Roll System with a Rectangular Target

Huang Yun-xiang Wen Wan-yu Sun Jia-wei Huai Chuang-feng Zeng Hai-feng Zhong Fu-hui

2015, 43(11):  81-86.  doi:10.3969/j.issn.1000-565X.2015.11.012

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In this paper，a sputtered theoretical model is proposed on the basis of the roll-to-roll system with a rec-
tangular target，and with the help of the simulation software Matlab，it is used to analyze the film thickness uniformity of the rolled flexible substrate，whose width is 100mm with a bending radius of 100mm and a bending angle of 80°． First，in the stillness of main roller，the situation of the film thickness uniformity error is investigated by adjusting the geometry size of target and the substrate-to-target distance． The results show that the film thickness uniformity error as a whole decreases with the increase of the geometry size of target，and that as the substrate-to-target distance increases，the middle parts of the film thickness uniformity error first increase and then decrease，while both sides of the film thickness uniformity error decrease． Next，in the rolling condition，the distribution of the film thickness uniformity error is discussed by adjusting the substrate-to-target distance and keeping a constant geometry size of target． It is found that the film thickness uniformity error first increase and then decrease as the substrate-to-target distance increases． Simulaiton results also show that the rolling film thickness uniformity error locates between the middle maximum of the stilling film thickness uniformity error distribution curve Max-Min and the average of the reference points on this distribution curve． Through the simulation of the proposed model，the rolling film thickness uniformity error on the basis of the roll-to-roll system with a rectangular target can be predicted quickly and the number of debugging can be reduced significantly．


Automotive Engineering

Integrated Chassis Control of Distributed Drive-by-Wire Electric Vehicles

Chen Guo-ying Zheng Hong-yu

2015, 43(11):  87-95.  doi:10.3969/j.issn.1000-565X.2015.11.013

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In view of the characteristics of distributed drive-by-wire electric vehicles with four-wheel drive/brake/
steering independently，an integrated chassis control strategy is proposed on the basis of layered architecture． The strategy mainly includes three parts，namely，reference targets setting，integrated control layer and control allocation layer． The reference target setting is aimed to realize the conversions from the driver's operations to the control targets of vehicle，and the control targets in the horizontal direction of vehicle are divided into longitudinal acceleration or deceleration features and lateral handling and stability． The role of integrated control layer is to achieve the multi-objective optimization of vehicle control force and moment by means of model prediction control (MPC)，which is a kind of local optimization algorithm of feedback correction features． The control allocation layer is used to realize the allocation of driving forces and the steering angles of wheels by minimizing the tire load ratio of each wheel． The results of the simulations and the validations on the real vehicle at a low speed indicate that the proposed strategy can help the vehicle to track the references quickly and improve the stability of vehicle by adjusting the negative rate of each wheel to be approximately equal．


Power-split Hybrid Electric Vehicle Acceleration Performance Optimization

2015, 43(11):  96-104.  doi:10.3969/j.issn.1000-565X.2015.11.014

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Acceleration performance is one of the important vehicle performance indicators. To solve the optimization problem of acceleration performance, dynamic programming problem is established by transforming the full-load acceleration progress to Multi-level decision-making process according to vehicle speed. Models for the novel power-split hybrid vehicle were established and the globally optimized control strategy was obtained on Matlab platform. Dual-motor torque figure was established while motor speed ratio and battery power band were defined to analyze the control strategy. The vehicle test result of optimization for power performance showed, 0ne-hundred-kilometers acceleration time was decreased by 15.7 percent. The control strategy based on dynamic programming significantly improves the vehicle acceleration performance.

Ride comfort study of 6×4 commercial vehicle considering frame flexible

Kim Kyongil Guo Rui Zheng Ling-ling Guan Hsin Jong Chanhyok

2015, 43(11):  105-111.  doi:10.3969/j.issn.1000-565X.2015.11.015

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In order to predict the ride comfort and optimize the design scheme during the initial design stage，a
half car vibration model of 6 ×4 commercial vehicles is constructed by taking into account the frame flexibility，and random input running tests are simulated． Next，the influences of vehicle suspension，cab suspension，engine mount and seat suspension on the ride comfort are analyzed． Then，a frame bending model is constructed by means of the assumed mode method，and the influence of the frame flexibility on the ride comfort of a whole vehicle is revealed． Furthermore，the influence of main vehicle parameters on the ride comfort is also evaluated through sensitivity analysis． Finally，the optimal matching of primary suspension and secondary one is processed by using the particle swarm optimization (PSO) algorithm． Simulation results show that both the stiffness of the first axle suspension and the first bending vibration of frame greatly affect the ride comfort，and the cab suspension and the seat suspension contribute most to the ride comfort．


Equivalent Fuel Consumption Minimization Strategy Based on Energy Recovery

Miao Qiang Sun Qiang Bai Shu-zhan Li Guo-xian

2015, 43(11):  112-118.  doi:10.3969/j.issn.1000-565X.2015.11.016

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In the energy strategies of hybrid electric vehicles，traditional equivalent consumption minimization strategy (ECMS)，which has a feedback circuit on the basis of the battery state of charge (SOC)，may lead to an
increase in fuel consumption because the inappropriate value of punishment function causes excessive-punishment．In order to solve this problem，a method on the basis of variable reference of SOC is proposed． In this method，with the pre-knowledge on the driving cycle，the cycle is divided into several kinematics fragments． In arbitrary fragment，the value of braking recovery energy in this fragment is subtracted from the initial residual capacity value of battery，and the difference value is taken as the new SOC-reference of punishment function when the ECMS tends to discharge largely． On this basis，an equivalent factor is established． Finally，a simulation model with ECMS framework is run under the NEDC cycle． Simulation results show that，in comparison with the traditional ECMS on the basis of the fixed SOC-reference，the proposed method helps improve fuel economy and maintain power balance．


Mechanics

W-R Method for Blast Ｒesistance Design of Laminated Glass

Zhang Hong Deng Han-guo Yao Xiao-hu Long Qian

2015, 43(11):  119-126.  doi:10.3969/j.issn.1000-565X.2015.11.017

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 he blast resistance design of laminated glass helps to reduce the personal injury caused by explosive
blast． The traditional blast resistance design with p-i diagram，where p is overpressure and i is positive impulse per unit area，does not take into consideration the effect of negative phase of blast． However，the negative phase can significantly affect the dynamic response of laminated glass． In order to solve this problem，the effect of the negative phase of blast on the p-i diagram is simulated by means of the finite element method． Aiming at the deficiency of the p-i diagram design method for blast resistance，a design method named W-R method，where W refers to explosive equivalent and R refers to explosion distance，is developed for blast resistance． In comparison with the p-i diagram design method，the W-R design method is more feasible for the blast resistance design because the W-R diagram has a simpler form and is more regular and more intuitional． Furthermore，the effects of the geometric parameters of laminated glass on its impact resistance are qualitatively analyzed，and by taking the critical damage of laminated glass as the benchmark，an empirical W-R formula is fitted to evaluate the blast resistance of laminated glass，which can provide guidance for the blast resistance design of laminated glass．


Investigation into Aerodynamic and Hydrodynamic Characteristics of Trans-Media Vehicle

Yang Hai-yan Lin Shu-yu Lin Ke

2015, 43(11):  127-132,144.  doi:10.3969/j.issn.1000-565X.2015.11.018

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The huge physical-characteristic differences between air and water would produce complicated impact on
the dynamic environment of trans-media vehicles． In this paper，with the Reynolds number (Re) as reference，the dynamic property of the vehicles crossing different fluids are simulated by using the software CFX to design cases． Simulation results show that there exists a Re inflection point in the flow field during the crossing process，and that，when Re is less than the inflection point，if the Re of the air and the Re of the water are the same，the change trends of aerodynamic parameters and hydrodynamic ones with the attack angle are consistent and their numerical values are similar，and if the Re of the air is close to that of the water，there exists a matching range between flight speed and submerged speed，in which the aerodynamic characteristics are shown to be similar to the hydrodynamic ones． The conclusions can provide a basis for the design of voyage control．


Analysis of Wave-Induced Seepage Effects on Bottoms of a Pair of Porous Vertical Circular Cylinders

Huang Hua Chen Rui-zhi Zhan Jie-min Bao Yun Zeng Zhao-luan

2015, 43(11):  133-144.  doi:10.3969/j.issn.1000-565X.2015.11.019

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Vertical circular cylinder or group cylinders are widely used in coastal and ocean engineering, which are one of the most common type of the ocean engineering structures. In this paper, based on linear water wave diffraction theory and wave induced seepage consolidation theory ,the analytical solutions to the diffracted water wave-induced seepage pressures referring to porous multiple vertical circular cylinders resting on permeable elastic seabed are derived by applying the eigenfunction expansion approach, and then the wave-induced lift force and overturn moment caused by the seepage pressure on the bottoms of a pair of vertical cylinders are accordingly evaluated and are compared with direct diffracted wave force and moment. The results illustrate that the porosity of the lateral surface of the circular cylinder may result in a significant reduction in direct horizontal wave loads, and will lead certain reduction in wave-induced seepage overturn moment on the bottoms of a pair of circular cylinders. The variation of ocean wave condition and structure geometry condition may have some influence on wave-induced seepage loads, especially on seepage moment. In certain condition, wave-induced seepage loads may have same order of magnitude as the direct wave loads. Furthermore, compared with compact cylinders, the porosity of a pair of the circular cylinders may also lead more similarity of the variation of wave-induced seepage loads on two cylinders.

Investigation into Fatigue Ｒeliability of MSD Structure by Modifiable Division of Cyclic Loading Method

Xue Xiao-feng Zheng Xiang-wei Feng Yun-wen Feng Yuan-sheng

2015, 43(11):  145-150.  doi:10.3969/j.issn.1000-565X.2015.11.020

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The strength will degrade due to the MSD(multiple site damage) in the structure, to avoid the catastrophic failure, the crack growth and reliability of the MSD structure should be evaluation exactly. Considering the lognormal distribution of fracture toughness and stress intensity factor, the multiple-crack propagation reliability model of multiple-Crack structure is developed, including stress strength reliability interference model and second boundary theory. In term of characteristics of MSD cracks growth, two influencing factors having relation with speed of cracks growth are presented. Based on Pairs equation, recursion relation of cracks growth length has been deduced. Combining with the modifiable division of cyclic loading method, the computation work of fatigue crack growth is reduced greatly. Finally, the calculation method of the failure probability for the MSD structure due to the crack propagation is presented. The fatigue life and failure probability of one type MSD crack configuration, which of the collinear fastener holes in rimmed thin panel, is analyzed. Compared with the experiment results, the calculation results show the failure probability of MSD panel is reasonable.