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2007 Vol. 33, No. 01

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Influence on flow around mid-part of slender at high AOA by sweep wing
Li Guohui, Deng Xueying
2007, 33(01): 1-4.
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The flow around a slender was fixed in this way which a tiny pert urbation was located on the nose of the slender. The influence on flow str u cture and aerodynamic of a slender by sweep wing at high angle of attack was studied. The experimental results indicate that at angle of attack 30°,the fl ow and pressure distribution of mid-part leeside of a slender are dominated by sweep wing and forebody vortices. At angles of attack α=40°~60°, sweep wing dominates the flow around the mid-part of a slender only, and the flow of mid-p art leeside of a slender becomes full separate flow, the pressure distribution o f mid-part leeside of a slender retains constant.
Process mechanism of synthetic jet and its effect on the mixing in coaxial jets
Liu Yanming, Wu Naiming, Dong Jinzhong, Zhou Sheng
2007, 33(01): 5-9.
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Two-dimensional unsteady numerical simulation was carried out to inve s tigate the flowfields surrouding a synthetic jet actuator and its effect on the mixing in coaxial jets. The synthetic jet flowfield and the coaxial jets flowfie ld were investigated. The results show synthetic jet comprises a series of vorte x pairs, which distribute around the centerline symmetrically. Its frequency kee p same to the actuator′s frequency. This is a disturbed force for the outer flo w field. The movement velocity of vortex pairs is nearly constant. The formation a nd development of the outer flowfield have the same rule as that of the inner fl owfield. But they are opposite to each other at the certain moment. As a result of actuating device, the centerline velocity distribution shows that the amplitu de decreases gradually, which represents the radical characteristic of vorticity d evelopment. The mixing ratio of coaxial jets increases comparatively because of the synthetic jet actuators, and the mixing effects in coaxial jets also become more agreeable.
Rotor dynamic analysis based on solid element
Chen Meng, Hong Jie, Zhu Bin, Liu Shuguo
2007, 33(01): 10-13.
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In modern times, dynamical interaction of different structures should be taken into account in aero-engine vibration analysis, as a reason, the engine should be modeled by solid elements. To take the gyroscopic effect into account in the analysis of complex rotor dynamics characteristic, based on the dynamics finite element equation of 8 node element CHEXA, a rotor dynamic analysis software package was developed on the platform of MSC/NASTRAN with the DMAP process by adding gyroscopic torque , Coriolis acceleration and centrifugal force to it. Dynamic analysis of typical models were performed, including a diagonal compressor and a conical shell. The results of calculation and experiments were compared. Typical vibration characteristics as rotor bending, shells traveling waves and various sectional vibrations were summered. The results showed that traveling waves and rotor precessions could be taken into account accurately while using the author's method. For the vibration of complex rotors can be calculated with the method, the foreground of the use in full modeling in multi-field was figured out.
Aerodynamic optimization method of transonic fan rotor based on BVF
Wu Hong, Li Qiushi, Guo Ming, Zhou Sheng
2007, 33(01): 14-17.
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The aerodynamic optimization of a transonic fan rotor was implemented by controlling the BVF(boundary vorticity flux) distribution on rotor blade. A novel objective function of torque associated with BVF was used to optimize the blade configuration. The physical sources of separated flow could be probed on r otor blade through the BVF diagnosis, which was a novel diagnosis method based o n local dynamics. The shock structure was showed clearly on the rotor blade in th is diagnosis method. Although the torque of the optimized rotor was increased, t he shock strength was decreased and the separated flow was controlled better, as the BVF distribution was better than before. The results of 3D CFD(computationa l fluid dynamics) analysis indicate that not only the total pressure ratio of r otor is increased by 7.69%, but also the adiabatic efficiency is increased by 1 .92% too. The optimized rotor has a higher performance over a wide range of mass flow. The optimization method based on BVF can play an important role in the optimization design of fans/compressors.
Simulation of hypervelocity impact to honeycomb sandwich
Xu Xiaogang, Huang Hai, Jia Guanghui
2007, 33(01): 18-21.
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Honeycomb sandwich is a special configuration which often used in spac ecraft . The method of smoothing particle hydrodynamics (SPH) in the hypervelocity impa ct simulation to the honeycomb presents two questions: it is problematic to mode l the honeycomb, the distance between the neighboring particles should be equal , however, the honeycomb is so thin that the particles would be created too much t o compute. The ANSYS parametric design language (APDL) and the ANSYS user interf ace design language (UIDL) were integrated to create the honeycomb core. The pro g ram was written in APDL, and the APDL program was integrated in the ANSYS user i nterface with the UIDL. Arbitrary hexagon honeycomb core can be created in this method expediently. The honeycomb core was simulated with shell element while th e front facesheet and the rear facesheet was simulated with SPH element in the s imulation. The hole size by the simulation was compared with the experim ent which shows almost equal in size. It is confirmed that the method is suited to the simulation of hypervelocity impact to honeycomb sandwich.
Numerical simulation analysis of leakage flow in compressor cascade with splitter
Li Haipeng, Liu Huoxing
2007, 33(01): 22-26.
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3D numerical simulation with S-A turbulence model was applied to the low subsonic leakage flow analysis of traditional compressor cascade and splitter compressor cascade with clearance. The result shows: short splitter has weak influence on the suction pressure distribution, leakage flux and the position leakage vortex rotated on the tip of principle blade. When the attack angle increased, the principle blade leakage flow would develop to the splitter clearance and result in second leakage, this would worsen the flow and performance on the cascade tip. When splitter is moved to principle blade suction, the second leakage becomes more intense. When the case is moving, the second leakage on the tip of splitter happens more easier, but the flow on the cascade tip is improved. With the change of attack angle, the position where principle blade leakage flow interacted with the splitter clearance is changed , this change results in various flow models on the tip of principle blade.
Base operational unit corrective maintenance process modeling and simulation
Guo Linhan, Kang Rui
2007, 33(01): 27-31.
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To analyze base operational unit(BOU) corrective maintenance stratagem and accurately calculate fault recovery time, BOU corrective maintenance proces s simulation models among depots was set up, the models in dep ot was also set up according to system engineering modeling ideology, BO U corrective maintenance activities was described. Accumulate maintenance rate(A MR), maintenance mode rate(MMR) and remove rate(RR) parameters were presented. M easurement methods based on the parameters were given via to which BOU corrective maint enance process was quantitatively analyzed. The simulation algorithm was m ade out according to Monte Carlo simulation method. Theory and technology means were offered to equipment designer in the supportability design and analysis wor king areas. The corrective maintenance concept(CMC) was validated in an airplane individual unit example making use of simulation tests. The effects to support resource and maintenance time was analyzed with the bettered CMC.
Impact of IGV/rotor interaction on rotor flow field in an axial compressor
Gong Zhiqiang, Lu Yajun, Li Zhiping, Li Maoyi
2007, 33(01): 32-37.
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The IGV/rotor interaction phenomenon in turbomachinery has been resear ch focuses for years, but until now such researches have been restricted to qual itative description of flow phenomenon without theory instructions. So this very important unsteady phenomenon can not be included in turbomachinery design regi me to further improve turbomachinery performance. By the theory of flow instabil ity and receptivity, the rule of using this phenomenon to improve turbomachinery performance can be found. The IGV/rotor interaction phenomenon in a one stage l ow speed axial compressor was investigated experimentally. A 2D digital particle image velocimetry was used to acquire the quantitative flow field structure aro und the rotor with and without IGV. The rotor flow is evidently unsteady even un der steady flow condition. With IGV/rotor interaction, the rotor flow field was changed significantly. The intensity of rotor wakes was reduced, flow separation on rotor suction side was suppressed and the tip leakage flow was suppressed pe riodically. Besides IGV wake interaction and periodic variation in flow angle, d ifferent response of the rotor unsteady flow to different unsteady IGV/rotor exc itation frequency was decided to be the most important reason for the compressor performance changes.
Dynamic characteristics of high temperature superconductor bulk magnetic suspension system
Wen Zheng, Liu Yu, Yang Wenjiang, Qiu Ming
2007, 33(01): 38-41.
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The magnetic levitation technology was regarded as a preferable alternative for the next generation of launcher system owing to its cost-effectivenes s and perfect performance. A research plan was performed in our lab by constructing a scale-model suspension system with high temperature superconduct o r (HTS) bulks over a Nd-Fe-B guideway for launch assistance. An dynamic experi me ntal platform was established to investigate the dynamic characteristics includi ng amplitude frequency response characteristic, damping characteristic, levitate d stiffness and so on. The experimental result show that the resonant frequency is decreased with the increase of the field cooling(FC) position and reach lowes t at zero field cooling(ZFC) position. The static-stiffness is decreased with the increase of the suspension gap and dynamic stiffness was influenced by the FC position. Damping, the ability of a system to decrease oscillatory seems not e nough to stabilize the levitation system during the low frequency and also was i nfluenced by the vibration speed. By qualitative analysis the dynamic performanc e which could provide a evaluation for the stabilization of the magnetic levitat ion system and also provide a guidance for stability and security of the launch assistance suspension system.
Numerical simulation of secondary gas injecting for thrust-vector-control
Wu Xiong, Zhang Weihua, Wang Zhongwei
2007, 33(01): 42-45.
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The complex inner flow-field of secondary gas injection for solid rock et motor were numerically investigated using three-dimensional average Favre N -S equations and the k-ε turbulent models. Three-order spatial scheme an d implicit point Jacobi algorithm were used to solve these equations. The basal explore of the integrant scheme for secondary gas injection vector nozzle was do ne by dint of the numerical simulation technology. The influences of the flow-f ield of secondary gas injection and the side force by different injection parame ters were studied and investigated. The results show that the position of the in jection hole, the injection total temperature and total pressure that affected t he side force of the nozzle are coupling. Moderate position of the injection ho le, hot gas and biggish injection total pressure increases the side force and ve ctor angle of the nozzle effectively. The hot gas injection system has higher ef ficiency. The side force increases linearly with the augmentation of the seconda ry injection total pressure.
Aircraft landing gear system dynamic modeling and simulation
Li Bo, Jiao Zongxia
2007, 33(01): 46-49.
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Aircraft interacts with the ground through landing gear system, wh ile taxiing down the runway. Owing to the changed forces and moments acted on th e aircraft, the landing gear shocks, and consequently results in the shift of th e aircraft Euler angle. In order to study the aircraft taxiing characteristics, considering the aircraft’s attitude and rotation, the aircraft landing gear sys tem mathematical model is built including tire model, ole-pneumatic shock strut model, landing gear walking model and main wheel brake device model. Considering ABS(anti-skid brake system) control and nose wheel manipulation, the landing g e ar system model is applied to aircraft six degree of freedom model and been simulated. The si m ulation results show that the aircraft landing gear system mathematical model es tablished is correct. Moreover, it establishes the foundation to the research on the aircraft taxiing characteristics.
Geometry nonlinear analysis of composite thin walled beams
Shi Qinghua, Xiang Jinwu
2007, 33(01): 50-54.
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A new geometry nonlinear finite element model for composite thin walle d beams has been developed based on the complex deformation characteristic of th e composite thin walled beams. Supposed the strain quadratic varies along the th in-walled, introducing the complex cross-section of beam was simulated by 9-node pla ne element and the out-of-plane warping displacement was simulated by 27-node so lid element. Based on the Hamilton principle, nonlinear finite element theory an d the Total Lagrange formulation, the geometry stiffness matrix was formed. The analytical model is proved correct through several examples. The model can be used in analysis of thin-walled composite beams, the warping d e formation has evidently affected on composite thin walled beams, compared with r elated literatures numerical results, the advantage of this model has been showe d.
Study on H.323-based distributed gatekeepers
Shen Wei, Ding Rong, Zhang Hui
2007, 33(01): 55-58.
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The scalability of H.323-based video conferencing system is closely re lated to the architecture of gatekeeper (GK). A distributed H .323 gatekeeper architecture based on multiple zones was proposed, providing the solution for the deployment of multimedia video conferencing system on the large scale netwo rk. This architecture did not only conquer the drawback of centralized architect ure and hierarchical architecture, but could balance the load between gatekeeper s. Design of GK-level signaling message routing based on alias format was used t o solve the communication problem between endpoints registered in different zone s. In the zone, the centralized architecture was adopted and the main-GK manage d the slave-GKs. Balancing load factor algorithm(BLFA) was presented to balance the load between gatekeepers.
New extended workflow net for formalizing workflow patterns
Zhang Liang, Jin Maozhong, Yao Shuzhen
2007, 33(01): 59-62.
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To satisfy the enterprise process modeling requirements in the ability of powerf ul expression and analysis, a new extended workflow net(EWF_net) was proposed fo r formalizing workflow patterns. EWF_net extended workflow net(WF_net) by adding some mechanisms, and improved the power of describing dynamic workflow mode l of WF_net. EWF_net was designed for directly describing various comp lex process, especially multiple instances, cancel activity, advanced parallel a nd synchronization which were not supported by most Petri-net models. Control v ariable was introduced in EWF_net for describing the relevant data of workflow m odel. In EWF_net, a special transition,transfer transition was introduced for s upporting dynamic routing of the model. A formal correctness analysis method of EWF_net was given based on the analysis techniques of Petri-net. The correctness analy s is of EWF_net consisted of the analysis of consistent and the analysis of soundne ss of corresponding WF_net. Finally, an application example was described and an alyzed in EWF_net which showed its power of description and analysis.
New solution for IPSEC passing through NAT
Peng Jinbing, Long Xiang, Gao Xiaopeng, Chen Xianqin
2007, 33(01): 63-66.
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The application range of IP security protocol (IPSEC) is badly restric ted due to the incompatibility of IPSEC and network address translator (NAT). Th e rule that must to be followed by the solutions for IPSEC passing through NAT i s that IPSEC pass through NAT without any changes to the routers and NAT on the Internet. There are limits to the current three solutions. It can barely be real ized to execute the NAT ahead of executing the IPSEC. It is difficult to deploy the realm specific IP(RSIP). The incompatibility of IPSEC and NAT can only be solved partially by user data packet(UDP) encapsulation of the IP enca psulating security payload(IPSEC ESP) packets. A new solution, UDP encapsulation of IPSEC packets, was developed. The new solution eliminates the impact from NA T to IPSEC by protecting the origin IP addresses and ports of the IPSEC packets through encapsulating the IPSEC packets with UDP header. The feasibility of this solution was demonstrated. The analyse shows that the new solution has evident advantages over the others and can remove the incompatibilities between IPSEC an d NAT effectively and expediently.
Fault diagnosis based on wavelet package and Elman neural network for a hydraulic pump
Liu Hongmei, Wang Shaoping, Ouyang Pingchao
2007, 33(01): 67-71.
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Considering the low signal-to-noise, faint failure characteristics of hydraulic pump, and slow convergence speed and the instability of BP network , a new fault diagnosis method based on the wavelet package analysis and Elman n eural network is presented. The wavelet package analysis is adopted to eliminate the noise in the actual signals and to extract the fault characteristics. Throu gh signal decomposition and single reconfiguration with wavelet package, the noi se can be eliminated from signals to strengthen the failure signal and to extrac t fault feature in every frequency bands effectively. Energy of various frequenc y bands acting as the fault feature vector is input into the improved Elman neural n etwork to realize the mapping between the feature vector and the fault mode. The experiment results verified the effectiveness of the proposed method in the hydraulic pump faul t diagnosis.
Imaging algorithm for high-resolution space-borne spotlight SAR data based on two dimension deramp processing
Wang Pengbo, Zhou Yinqing, Chen Jie, Li Chunsheng
2007, 33(01): 72-75.
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Reduced the data rate is one of the difficulties in high-resolution space-born e spotlight synthetic aperture radar (SAR). Based on two-step focusing algorith m and chirp scaling(CS) algorithm, two dimension deramp chirp scaling(TDDCS) alg orithm for processing high-resolution space-borne spotlight SAR data was prese nted. The algorithm starts with raw data dechirped in range. First, the azimuth s pectral folding phenomenon is overcome by using azimuth deramp processing, and the chirp signal is recovered by using range deramp processing. Second, the prec ise range cell migration correction is achieved by chirp scaling processing and phase compensation. Lastly, the azimuth compression is performed by match filter , and the image is received. Based on the squinted equivalent range model, the c omplete derivation of the algorithm was presented and the realizing approach was given. The computer simulation shows the validity of the algorithm.
Space-time interference suppression technology of satellite navigation receiver
Zhang Lin, Chu Haibin, Zhang Naitong
2007, 33(01): 76-80.
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If several interferences (including broadband and narrowband) appear o r satellite signal and interference have similar direction of arrival, the locat ion precision decreases below the normal level required in satellite navigation receiver. Therefor a constrained space-time adaptive processing(STAP) approach was propos ed to ensure low suppression of satellite signal which is direction si milar with interference by obtaining direction information of satellite and inte rference as constraint ahead. Simulation suggestes that it maintains high inter ference suppression degree (above 40dB), increases suppression freedom of degree , and ensures the normal reception of satellite signal while satellite and interf erence are direction similar (almost 10°). The method can increase the anti-ja mming ability of the regional satellite navigation receiver in complex electrica l surroundings.
Coordinated target assignment in multi-UAV based on satisficing decision theory
Liao Mo, Chen Zongji
2007, 33(01): 81-85.
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A key problem addressed in study of uninhabited aerial vehicle (UA V) is to coordinated assign targets in multi-UAVs. The mathematic model for mul t i-UAV cooperative target assignment problem was built, when assigning targets i n multi-UAVs, the model considered about effect of the battle field situation, a n d differences in different UAVs and targets. A multi-UAV target assignment algo r ithm based on the satisficing decision theory was presented. Each individual pro posed its satificing set, the algorithm searched the global optimal assignment s cheme on all individual satisficing sets. To settle the multi-target assignment problem, the algorithm was applied by taking the atta ck scheme as the element of the individual satisficing set. To expand the proble m size, a hierarchical structure was presented by which the algorithm was extend ed to the hierarchical form. The method evidently can improve the searching efficiency and obtain the optimal results.
Application of fuzzy sliding mode iterative learning control algorithm in hydraulic servo system
Wang Yan, Fu Yongling
2007, 33(01): 86-89.
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The common P(proportion) type or PD(proportion and differential) type ILC(iterative learning control) is difficult to apply in a hydraulic servo syste m because of its low convergence rate. To improve the convergence rate, a new IL C based on a sliding mode fuzzy control is presented which combines a sliding mo de control with ILC. The new algorithm makes use of the fast response merit of a sliding mode control to quicken the convergence of ILC. The fuzzy control in th e algorithm can smooth the control signal and lessen the common dithering of sli ding mode control. The FSMILC(fuzzy sliding mode iterative learning control) is an iterative learning control algorithm essentially, which takes the function of a sliding mode control as the input of fuzzy control and takes the fuzzy contro l output as the control increment of iterative learning control. The simulation results indicate that the new algorithm is effective, which can achieve higher s peediness than that of iterative learning control of P type or PD type.
Three-phase aeronautical active power filter based on space vector and one-cycle control
Wang Yong, Shen Songhua
2007, 33(01): 90-93.
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A new control method for the three-phase aeronautical active power filter was proposed. According to the ideal of space vector, the t hree-phase voltage was divided to six regions, where the model of one - cycle control was established. The proposed controller need only one integrato r with reset, three comparators, two flip-flops and some linear components. In e ach region, one leg works under low frequency and other two legs work under hi gh frequency. The proposed controller, which is simple, robust and reliable, has the features of high efficiency, unified constant-frequency, high precision, effective compensation, and is desirable for industrial applications. The analysis, modeling, simulations and exper iments were carried out with the three-phase active power filter. Simulatio n and experiment results verify that the proposed three-phase three-legs act iv e power filter can dynamically and effectually compensate the harmonics and reac tive.
Decouple analysis and simulation of displacement control for cable-driven manipulator
Chen Weihai, Wang Huihua, Yu Shouqian, Lei Yinzhao
2007, 33(01): 94-99.
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To improve the load capacity of the manipulator, based on the geometry analysis and screw theory, the configuration design, c able-driven manner, and kinematics control for a cable-driven humanoid-arm ma nipulator were analysed. Firstly, aiming at the choice of cables-driven manner s, a cable-driven me chanism that is coupled between elbow and wrist, and between shoulder and elbow was designed. Secondly, taking the 7-DOF joints such as the shoulder, elbow and w rist as medium, the relationship between the end-effector and driven cables was a nalyzed, i.e. through considering the relationship among the end-effector′s po se and joint angles firstly for the manipulator, and then considering the relation ship among joint angles and corresponding length of cables, the kinematics of ca ble-driven manipulator can be solved. Lastly the simulation was realized. The s im ulation results show that the curves of manipulator′s joint angles and length o f cables are very smooth, and the error between actual trajectory and ideal traje ctory of the end-effector is very small. These prove that the proposed algorith m is correct, the cable-driven manipulator runs well, and proposed approach can e ffectively overcome the negative effects from general robot brought by its deadw eight.
Comparative analysis on kinetics with redundant driving of Cartesian serial-parallel manipulator
Luo Jianguo, Lu Zhen
2007, 33(01): 100-104.
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Redundant driving structure designed based on a new type of universal Cartesian serial-parallel manipulator, kinetics equations and Euler equations constructed, complete analysis of each jointed points of the moving platform carried out, inverse kinetics solution can be obtained with the given parameters, which include the position and orientation of the manipulator, applied force on the output shaft, parameters of motion of output shaft and connecting bar and sliding block, computer programming adopted to get the valid data and its figure, thus found the perfect show of this redundant driving structure compared to the primary mechanism without redundant driving.
Optimal motion planning of a three-link planar under-actuated manipulator system
Liu Shengping, Lu Zhen, Wu Licheng
2007, 33(01): 105-109.
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An optimal motion planning scheme for a three-link planar under-actuated manipulator moving between two stationary states was considered. The manipulator has two prismatic joints that are actuated, while the third joint of the manipulator is a revolute passive joint which has neither an actuator nor a holding brake. The dynamic constraint on the free link is shown to be second-order nonholonomic. The states and inputs of the system were expressed in terms of higher order derivatives of a subset of states by using coordinate and input transformations. The explicit expressions for the states and inputs were used to change a constrained dynamic optimization problem into an unconstrained one. The necessary conditions for optimality were derived by calculus of variations.The scheme was applied to a planar PPR under-actuated manipulator and numerical results were reported.
Bearing capacity and ductility of reinforced concrete columns with Z-shaped cross-section
Jiao Junting, Diao Bo, Ye Yinghua, Li Shuchun
2007, 33(01): 110-114.
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Against there is no design specification for reinforced concrete (RC) columns with Z-shaped cross-section in the technical regulation of structure w it h special shaped columns, the bearing capacity and ductility of RC Z-shaped cro s s-section were computed by utilizing the nonlinear analysis of RC cross-sectio ns subjected to biaxial bending and compression and its computer program. Some fact ors affecting the bearing capacity and ductility of RC Z-shaped cross-section, were researched, for example ratio of axial compression, loading angle, reinfor ced ratio, concrete strength and ratio of limb length to limb thickness, and some c urves of the bearing capacity and ductility were drawn. Some favorable results were obtained: the bearing capacity is mainly affected by ratio of axial compres sio n, loading angle, concrete strength, long reinforced ratio and ratio of limb len gth to limb thickness mainly affect, and hoop reinforcement has little affect. r atio of axial compression is the most important affect factor for the ductility, but there is a little affect for the ductility from ratio of limb length to lim b thickness.
Uncertainty modeling in multidisciplinary design optimization
Han Minghong, Deng Jiati
2007, 33(01): 115-118.
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Uncertainty is pervasive throughout the design process of complex engineering system. The sources of uncertainty in multidisciplinary design optimization(MDO) were summarized and classified into three categories: requirement error, input data error and model error. A mathematical model was built up for the estimation of propagated uncertainty in MDO system that contained two coupled disciplines(subsystems), which represented the relationship between input data error, model error and uncertainty in results of MDO system analysis to evaluate the influence of uncertainties for system performance. The agreement of the final computation results with the experimental data indicates this model is effective and reliable. Having extended, this model could be used to estimate the uncertainty in results of MDO system analysis, which contains more coupled disciplines(subsystems). The research is useful for the development of robust MDO methods.
Analysis of the properties for epoxy curing agents with reactivity and toughening
Yang Yang, Chen Gong
2007, 33(01): 119-122.
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A type of novel epoxy curing agent, Bis(2-hydroxy-3-amidoethylaminemethyl-5 -nonylphenyl) methane(BA) was synthesized from dimer which was obtained from n onylphenyl and formaldehyde. The structure of this curing agent was attributed b y IR and 1HNMR. The reactivity of the curing agent was investigated by using the differential scanning calorimetry(DSC), and the optimum content of BA used in c uring process was definited at 43.19% in weight. From the results of dynamic mec hanical analysis(DMA), the β- relaxation contributed by the nonyl of BA was con firmed, which increased the toughness of the cured resins. The results of mechan ical performance test demonstrates that the impact strength of the resins cured by BA was 36.91% higher than that of the resins cured by normal aromatic amine. In conc lusion, BA is a elasticizer and active curing agent for epoxy resins.
Product rapid design based on integrated knowledge model
Zhao Hui, Xi Ping
2007, 33(01): 123-126.
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The approach to improve the existing CAD(Computer-aided design) system s′ capacity in design knowledge reuse was discussed. The scheme and implementat i on approach of representing hierarchical knowledge and constructing integrated k nowledge model were proposed. Design knowledge was divided into three abstract l ayers: configuration layer, design layer and modeling layer. KFL(knowledge f usion language) and Open+ + of UG(Unigraphics) were adopted to represent and inte grate design knowledge in the three layers. A system frame supporting the genera tion and reuse of integrated knowledge model was designed. And the application o f the frame was illustrated by a system for the special retarder rapid design.

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