The major work of this paper is developed on the research of laminated composite shellssubjected to axial impact loads. Through the quasi-static compression test, its cushion energyabsorbing property is investigated, and finite element method is applied to simulate the dynamicresponse process of laminated shells under the drop impact.In ChapterⅠ, the history and real-life meaning in this field are introduced. The presentresearch status of composite structure is summarized as well.In ChapterⅡ, theories about the cushion energy absorbing property of the composite shells areintroduced, which are about the formula derivations of composite tube’s dynamic responseprocess, analyses of the energy dissipating principle through experiment, and influence factorsof structure’s crashworthiness.In ChapterⅢ, the axial compression test of laminated shells is carried out, and its results areanalyzed emphatically. The effects of the ply methods and initiation mode on specific energyabsorption are investigated, as well as the contrast of three initiation modes including chamferstructure, cusp structure and fillet structure, which help to find a method to enhance the energyabsorbing property of this material.In ChapterⅣ, Ansys/LS-DYNA is introduced about its finite element method. With it, twomodels are employed to simulate laminated composite shells under the drop impact, and thecontrast is made between simulating results and experimental data.In ChapterⅤ, the whole paper is summarized and some conclusions are obtained. Then, fartherinvestigations in this field are prospected.

Watermelon seed is rich in protein, fat and mineral elements, such as calcium, magnesium, phosphorus, potassium, sodium, which is one of the popular roasted seeds and nuts for its rich nutrition and savory flavor. Therefore, watermelon seed possesses highly economic worth. Although the planting of watermelon seed is extensive at the present time, the process is underdeveloped. The shapes of watermelon seed are similar but the sizes are different. The hull is hard and the clearance between the hull and the kernel is small so as to it is difficult to shell. The people not often eat watermelon seed, the old and the young degust discommodiously. All of them make the market and price restrained. Moreover, because the foreigners seldom eat watermelon seed, the export is limited. Therefore, the problem of how to process deep and how to suffice the demand come forth. Through investigation, making the hull ringent in advance can be effectual. While the handwrought way is preferred in many factories, which is inefficient and cost a lot. Thus research on ringent method of watermelon seed by mechanism is needful in production. In this way, the efficiency and quality will be improved, and the factories can produce largely.There are many methods to shell, such as mechanical, physical and chemic ways. Impact, milling, roll press and omnibus methods are general in mechanical ways. The physical ways include vacuum and high pressure approach. And the chemic ways use reagent to intenerate the hulls.At first, according to inland and oversea information on materiel characteristics and threshing technologies of some nuts, the physical and mechanical characteristics of watermelon seed are researched. The experiment scheme is determined, that is, taking width, moisture, loading velocity as factors and rupture force and deformation as indexes. The results show that watermelon seed is viscoelastic and the correlation between the above indexes and factors is linear and nonlinear. The function formula is established and the primary factors are found.Secondly, the geometrical dimension is researched, and the three-dimensional model is established by Pro/E. Based upon the three finite element models, the distortion, the stress and strain distributions of watermelon seed are analyzed by ANSYS/LS-DYNA.The optimal load is symmetrical surface load along the width orientation. At this situation, the trend of distortion and stress-strain distribution is beneficial for extending cracks, therefore, crevassing efficiently at the seed tip. All the researches provide specific directions for the design and improvement of equipment.Finally, the pivotal parts of the crevassing equipment are introduced, and the three-dimensional model is established by Pro/E. Through the experimentation of crevassing watermelon seed using the crevassing equipment which is produced, the parameter is the experiential data for the research of ringent method of watermelon seed by mechanism.

Bowl is one of the main parts of a centrifuge. The design and strengthcalculation of bowl directly affect the general service performance of centrifuge. Tomeet the requirements of strength, reinforced hoop is used on cylinder of bowl insome design and manufacture units. Thus, mastering the effect of reinforced loop onstress of cylinder is very important.On the problem of reinforcing loop, it is supposed that using loops is feasibleamong centrifugal industry standards of various countries. There are definitecalculation formulas for reinforced loop coefficient in the standards of BS EN12457、VDMA 24401-Ⅰand JB/T8051, but they have different regulations on this issue; Andpretension between loop and cylinder isn’t considered in them. Besides, they do nothold unanimous opinion on the question of when loops work on the bowl and howtheywork.It belongs to contact mechanics problem of the connection between loops andcylinder. Because the distribution of stress in the connection area is very complicatedand the certain amount of interference between loops and cylinder in the condition ofpretension, it is difficult to solve the problem of bowl contact in theory. The paper hasdetermined the influence laws of these factors that include the structure anddistribution along cylinder of loop and other factors by using finite element analysismethod. And the results reveal that: no matter if there is pretension between bowl andloops, the enforcement effect of loops whose axial size is lager than the radial size(that isa ? e) on cylinder is greater than other shapes of loop in the condition of equalcross- sectional areas of reinforcement hoop. When cross section , thedepth-thickness ratio?of loop cross-section has little influence on the stress result.No matter if there is pretension between loops and cylinder, the cylinder between twoloops is being reinforced just when the loop space (which r0 representsthe mean radio of cylinderδmeans the wall thickness of cylinder). Theenforcement effect is most significant when for definitive totalcross-sectional area of loop. The two methods for reducing the stress level of bowl,one of which is enlarging the pretension and the other is increasing cross-sectionalarea are equivalent.On basis of finite element analysis, several revising suggestions of the application scope of reinforced loop coefficient Z in JB/T 8051-1996Standard ofstrength calculation for centrifugal bowl are proposed in this paper.

With the development of science and technology, the mechanical manufacturing technology is stridden forward all in the high speed, high quality, high accuracy and low consumption. High speed machining is one of the four advanced manufacturing technologies. At present, multi-function machine tools such as turning-milling machine, drilling- milling machine, etc. have been developed. The tool system, which influences the quality and efficiency of the high speed machining, needs farther researches. Therefore, it is significant to design a multi-function main shaft and research on its tool system.Considering the finished works in the laboratory and actual conditions, the focal point of this research is placed on the global design of the machining end of the main shaft, the theoretical calculation and the simulation of the HSK tool-holder and its optimal selection.The cylindrical of the shaft is connected to the vacuum sucker through the flange, and the inner hole is combined with the HSK tool-holder for respectively turning and milling. Then the static and modal analysis are applied by using the finite element software ANSYS to check its intension.Based on the elastic-plastic theory, the model of the HSK tool-holder/shaft connecting is established and the displacement under centrifugal force is deduced. Then the static analysis is applied by using ANSYS to verify the theoretical solution above. The influences of pre-tightening force, magnitude of interference and rotational speed on the connecting performance of the connecting system are simulated.Finally, the priorities of the connecting systems with different parameters are obtained with the Analytic Hierarchy Process.

With the quickly requirement of petroleum and national strategy changement of oil production, the development of ocean oil industry has developed quickly in recent years. Our country along with the whole world is in a period of ocean oil industry. The deep sea technology has been regarded as important in the development of the industry, which developed well in West Africa, Brazil and Mexico.In the paper, a finite element analysis is done on a FDPSO’s riser porch structure system, which belongs to Murphy West Africa, Ltd, in order to ensure the safety of the structure. Firstly, the finite element model is set up by famous FEM software ANSYS program, every designed load case is solved by it; then, the solutions are gained from ANSYS postprocessor, which are checked by methods recommended by DNV and AISC; at last, a detail calculation on fatigue life of the structure is done. The results indicated that the new added riser porch structures have adequate strength to withstand all design loads; existing hull structure has also been evaluated and found sufficient.

With the quickly requirement of petroleum and national strategy changement of oil production, the development of ocean oil industry has developed quickly in recent years. Our country along with the whole world is in a period of ocean oil industry. The deep sea technology has been regarded as important in the development of the industry, which developed well in West Africa, Brazil and Mexico.In the paper, a finite element analysis is done on a FDPSO’s riser porch structure system, which belongs to Murphy West Africa, Ltd, in order to ensure the safety of the structure. Firstly, the finite element model is set up by famous FEM software ANSYS program, every designed load case is solved by it; then, the solutions are gained from ANSYS postprocessor, which are checked by methods recommended by DNV and AISC; at last, a detail calculation on fatigue life of the structure is done. The results indicated that the new added riser porch structures have adequate strength to withstand all design loads; existing hull structure has also been evaluated and found sufficient.

With the much lighter requirements of the machine’s structure and the fast development of Extreme manufacturing, larger machine tools become the main developing tide. Though steel structure develops quickly inside, only few large span surporting beams are used on machine tools, the research is mostly blank.The developing precess of steel structure and the beam’s traditional design method are introduced in this thesis, then the structure of one machine tool’s beam is analyzed and optimized, also does some valuable work for the future design,the main results are:Firstly, according to the real condition, with the FEA (finite element analysis) software ANSYS, this thesis predigests the beam and it’s load, analyzes the main out weight of the beam (the front door and the back shield), gets the main load of the beam.Secondly, with APDL language, the beam is built by parametric modeling, through controlling node’s number, automatic determining the load position and forcing loads are finished, the static, modal, buckle, dynamic condition are analyzed, the results that the rigid distortion and the whole stability are suitable but the transverse stability presents bad are obtained.Thirdly, analyzes the influence of beam’s parameters on the beam’s distortion, for example, when the parameter H1 gets larger, the UY becomes smaller, and the influence of the beam’s distortion on the frontdoor.Finally, presents an optimal design method with the definite beam displacement and span restriction.gets the optimal results.A normal method is provided to the future design and analysis of this style beam by this thesis, the method how to analyze and judge the rationality of this large span beam is given, finally the beam is optimized,

With the rapid development of the micro-electro-mechanical-system(MEMS)and the microelectronic industry,the miniaturized micro-products have been the focus. However,the traditional micro-fabrication technologies have been unable to satisfy the demands of processing three-dimensional microparts as well as the volume production, and the extending the multiplicity of engineering materials.Micro-extrusion,one of the microforming methods,can be used to form the microparts with complex structures in mass production.Warm micro-extrusion process is proposed to solve the insufficiency of cold and hot micro-extrusion,and the corresponding system of warm micro-extrusion is designed.In addition,the ABAQUS software is used to simulate the warm micro-extrusion.The concerning investigations are as follows:Firstly,the system of warm micro-extrusion is studied and self-designed,including laser heating part,extrusion mould,temperature controller for die heating,loading part, feeding mechanism and three-dimension micro-moving platform etc.Noncontact laser-assisted heating method is used to heat the workpiece.The workpiece can be selectively heated through controlling laser power and the spot diameter,which has the advantages of good controllability and high efficiency.The operating principle of the system is also described.Secondly,in order to study the “size effect” related to flow stress,the micro-compression experiment is carried on.And relations between flow stress and deformation degree,strain rate as well as different lubrication conditions have been investigated.Then,the correction of flow stress in compression is discussed,and bulging method is carried on to the flow stress revision,the maximum of revised flow stress reduces about five percents compared with the original stress.Obtained true stress-strain curve can be used as the input data for the following finite element analysis.Lastly,ABAQUS/Explicit module is used to simulate the process of warm micro-extrusion for the aluminum alloy,and to explore the flow behavior of billet in extrusion cylinder and the influences of different processing parameters on forming rules.The parameters’ effects on formability,such as forming temperature,extruding speed,different lubrication conditions,are analyzed mainly from equivalent strain distribution,stress distribution,extrusion force,temperature distribution and flowing rate.All the results provide the support to optimize the mould design.Crown in extruded parts is used as the standard to evaluate the formability in warm micro extrusion.

Piercing mill is the most important equipment on the rolling pipe line,and the frame is the nucleal component of the piercing mill.As the increased demant on the rolled product,and the improvement of the product quality, Piercing mill frame must be the higher carrying and rel- -iability .Because of the restriction of the working conditioninthe locale , the stress test on the dangerous place of the parts , can’t be carried out usually ,and to obtain the stress value of the piercing mill frame ,FEA method must be taken.In this paper, assembly of the Piercing mill frame is constructby using contact analysis technique and node coupling technique to make FEA.Aimed at the piercing mill frame which is prestress frame,the FEA use substep approach load ,that preload is a first step to load and work load as a second load, the rack in each step under the load deformation and stress distribution is obtained.According to the deformation of frame, the stiffness of the frame is calculate, and the Minnimum of assemblage clearance between roll-box and frame is determinedOn the basis of global analysis,submodel anslysis is used on the position of stress concentration; stress concentrtion improved effectively on the transition curved surface of pressure nut aperture by using strcture improvement. According to the deforming of frame pressure nut aperture, the Minnimum of assemblage clearance between pressure nut and frame pressure nut aperture is determined.

Dynamics of solid-fluid interaction is an important branch of mechanics, which studies the diversify behaviors of deform structures in the fluid fields and the influences of fluid by the deformation structures. The dynamics of solid-fluid systems have been widely applied in structure analysis as a focus fields.Our country as a great nation about goods transportation, the railroad tanker takes an important parts of train, it takes part in the main task of the liquid, the gas and the powdery things transportation. The railroad tanker inevitable appears light or intense vibration in the movement, which will cause intense interaction between the shell of tanker and the fluid in the tanker. So the security and the reliability will be affected. In the last few years, with the speed of train becoming faster and faster, the conventional method to solve the solid-fluid interaction problem can not solve all current problem completely. The rapid development of the computer enable the problem go further. As one of the approximate method, the numerical method can progressive improve precision by using the computer. It can also solve some problem of complex boundary condition, therefore the numerical method has been become the main method to solve the project question nowadays.After the analysis to the tanker’s internal fluid units and the three kinds of solid-fluid boundary units, governing equation about dynamics of solid-fluid interaction, such as the tanker, is obtained base on the generalized variation principle and Finite Element Method. And a procedure is established to calculate the frequency of the tanker. The results are compared with the references’. The theory is accuracy, which is needed in the project. Last modal analysis and response analysis of the tanker has done with ANSYS. The vibration modes are calculated about different filled-tanker. Deformation and stress values of the tanker under different frequent loads can be seen in the charts, which is important to the engineers to design and repair the tanker. It can help the engineers to found the potential danger, to make the tanker use more time, to improve safety and to reduce economic. It can also provide relevant data and theoretical to design and produce new tankers.