日本大地震影响船市几何

日本是全球第三大经济体,贸易大国,造船大国和船舶配套大国。3月11日的9.0级地震,以及强震引发的海啸不仅对本国船舶工业产生较大影响,同时也波及到国际航运业和中国船舶工业。     

Development of hot stamped center pillar using form die with channel type indirect blank holder

The hot stamping process has been used in the automotive industry to reduce the weight of the body-in-white and to increase passenger safety via improved crashworthiness. However, defects such as fracture and wrinkle occur when hot stamping is performed using a conventional drawing or forming method. In this study, a channel-type indirect blank holder (CIBH) is proposed to develop a high-strength center pillar in form-type hot stamping, so that the aforementioned drawbacks are overcome. This type of blank holder plays an important role in reducing severe wrinkling at the flange; such wrinkling leads to folding after the completion of form-type hot-stamping. First, we investigated the effect of the channel shape on the indirect blank holding force by using a simplified two-dimensional plane-strain stamping process. Second, we selected the slope angle and corner radius of the channel as the main shape parameters by finite element analysis and artificial neural network (ANN). It is known that fracture at the hot formed wall and wrinkle at the flange are significantly affected by the slope angle of the channel, and the appropriate value for eliminating fracture and wrinkle is determined to be 99°. By performing hot stamping using a form die with the selected channel, we can manufacture a high-strength center pillar without wrinkle and fracture.     

Influence of compliance for an elastokinematic model of a proposed rear suspension

The research is carried out to improve passenger’s comfort to increase the vehicles stability in dynamic conditions. The literature available in the automotive engineering considers different topics for studying suspensions. An example represents mechanisms structure and analysis (synthesis, kinematics, and dynamics) under various operating conditions. These aspects have been approached before analytically, numerical. The current paper studies the influence of the lateral force on the contact patch of the wheel and the corresponding variations of vehicle stability parameters, such as camber angle and wheel rear track. The study is performed for a newer innovative rear suspensions mechanism which does not have a wheel track and camber angle variation, relative to the chassis, when the suspension components was considered rigid. A numerical solution is obtained through a virtual model on several commercial codes: MSC Adams, Patran, Nastran. Concerning the analysed parametes, their variation increases as the applied force is increased. Moreover, the largest variation corresponds to the case were elastic bushings and deformable links are considered.     

Examination of PN emissions and size distributions of a hybrid city bus under real world urban driving conditions

Engine load-speed frequency map of a hybrid city bus, which operates on the routes of Sakarya Municipality, was compared with that of European Transient Cycle (ETC) and World Harmonized Transient Cycle (WHTC), which are the certification test cycles. It was observed that the hybrid city bus engine operates mostly at three main regions, which are idling (30% load and 750 rpm), motoring (0% load and 1200 rpm) and high load (80% load and 1800 rpm) conditions under real world urban driving conditions. However, engine load-speed frequency maps of the certification test cycles are significantly different and cannot represent the real world urban driving conditions of the hybrid city bus. Therefore, the Particle Number (PN) emissions of the hybrid city bus were investigated under real world urban driving conditions. The aims of work were to examine the effects of city bus hybridization on the particle emissions and develop PN emission factors. The PN concentrations and size distributions together with engine operating conditions were measured with a Particle Measurement Program (PMP) compliant system, which involves a condensation particle counter (CPC) and a particle sizer (EEPS). The measurements under real world urban driving conditions indicated that the emission factors of the hybrid city bus for the PN and Total PN are 8.99E+12 and 2.51E+13 #/kW-h, respectively. The PN size distribution measurements indicated that the particles up to approximately 20 nm are not very sensitive to changes in engine power and they are exist even during motoring conditions. But, the particles in the size range from 20 to 200 nm are very sensitive to sudden changes of the engine power.     

Calculation of Transient Stress Field During Laser Transformation Hardening Process

IntroductionHighpowerCOzlaserssdsetransformationhardeningtechniquehasbeensuccessfullyusedinindusnyforWYears.BecausethetemPeratUrefleldislocalizedinmaterialdurllglasertransfonnationhMngProcess,highthermstrCsswillgenerateinmatgrialduringlasertfansformationhardeningProcess.Therisalsohighresidualstressinmaterial,bothintCnsionandcomPression['-'].ComPressresidualstressishelptoincreasethefatigueldrimeofthelasertreatedmaterial,butthetensilestresswillshortenthefatiguelifetmeofthelasertreatedmator…     

RECENT DEVELOPMENT OF PROCESS SIMULATION AND ITS APPLICATIONS TO MANUFACTURING PROCESSES

l.IntroductionThemostboortantdrivingforceinmanufacturillistoPrOduCeabetterPrOductatalowercost.GenerallyeffecthemethodsinchideshOrtenintheleadtiminthedesigncyCle,andredUcinthetoolingcostandmaChinedOWnmeatProductionst4e.AllOfthemrewtabettertmderstandingofhO…     

Computer Simulation of Thermal-Mechanical Processing

AlterationIntroductionThereisastrongini6ractionamongtemPetalrefield,strCssfield,andmicrosttuctutulaltOrationinm8terialsduringtheirhotworking[l'2].Especiallyduringthecoolingprocess,inwhichtemPeratorechangnsgreatly,intendionsbecomemorecomplexbecauseoftransformationoccurmnce.Duringthehotdeformation,thingswillaPpearsuchas:a.hotdeformation,relatedtostressfieId,changesessentiallytheshaPeofmaterialsandcausesthevariationofthecontactstatebetWeenthedieandsample,resultinginchangeofthethermalboundnyco…     

跨世纪档案人才的培训与教育工作

阐述了跨世纪档案人才的培训目标、素质条件、选拔原则、培训内容及培训措施。     

国有小型运输企业股份合作制改造的思考

对国有小型运输企业实行股份合作制进行了探讨     

Dynamic response of offshore jacket structures under random loads

In this paper, the dynamic response of a scale model of a jacket offshore structure is investigated both theoretically and experimentally. The experiments were conducted both in air and in water. The in-water experiments were done in the towing tank of Memorial University to simulate the realistic operating conditions. The model was subjected to random wave loads. Froude's law of modeling was used to obtain the dimensions of the scale model based on the dimensions of an existing structure. The effects of varying the structure's weight, and the characteristics of the wave loading were investigated. The structure's weight was changed by adding weights to the structure's deck. A finite element model was designed to determine the dynamic response of the model. Excellent agreement between the experimental and theoretical results was obtained.The reaction force at the foundation was estimated from strain measurements and compared with the finite element calculations. Fair agreement was obtained.This work is the first stage of a project whose objective is to develop a method for structural damage detection using the free vibration response of the structure. The free vibration response will be obtained from the stationary random response of the structure using the random decrement method. Having an accurate model to describe the dynamic response of the structure is the first step in this study.