机械设计毕业论文中英文资料外文翻译文献(编辑修改稿)

机械设计毕业论文中英文资料外文翻译文献(编辑修改稿)内容摘要：

r fixtures needed? Can it easily be inspected? Can the workshop produce it? Is heat treatment necessary? Can parts be easily welded? 第 4页 Cost of operation． Are power requirements too large? What type of fuel will be used? Will operation cost be less expensive? (3) Cost of maintenance． Are all parts easily accessible? Are access panels needed? Can mon tools be used? Can replacement parts be available? (4) Safety features． Is a suitable factor of safety used? Does the safety factor meet existing codes? Are fuses， guards， and／ or safety valves used? Are shear pins needed? Is there any radiation hazard? Any overlooked ”stress raiser”? Are there any dangerous fumes? (5) Packaging and transportation． Can the machine be readily packaged for shipping without breakage? Is its size suitable to parcel post regulations, freight car dimensions， or trailer truck size? Are shipping bolts necessary? Is its center of gravity in a desirable location? (6) Lubrication． Does the system need periodic checking? Is it automatic? Is it a sealed system? (7) Materials． Are chemical， physical， and mechanical properties suitable to its use? Is corrosion a factor? Will the materials withstand impact? Is thermal or electrical conductivity important? Will high or low temperatures present any problem? Will design stress keep parts reasonable in size? (8) Strength． Have dimensions of ponents been carefully calculated? Have all the load cases be taken into account? Have the stress concentrations been carefully considered? Has the fatigue effect be puted? (9) Kinematics． Does it provide necessary motion for moving parts? Are rotational speeds reasonable? Could linkages replace cams? What will be the best 中英文资料 5 choice， the belts， chains or gears? Is intermittent motion needed? (10) Styling． Does the color have eye appeal? Is the sharp desirable? Is the machine well proportioned? Are the calibrations on dials easily read? Are the controls easy to operate? (11) Drawings． Are standardized parts used? Are the tolerances realistic? Is the surface finish overspecified? Must the design conform to any standards? (12) Ergonomics． Has the operator of the equipment been considered? Are the controls conveniently located to avoid operator fatigue? Are knobs， grab bars， hand wheels， levers， and dial calibrations of proper size to fit the average operator? 1． 4 A general procedure of machinery design Whatever design tasks the designers are expected to plete， they always， consciously or unconsciously， follow the similar process which goes as follows： (1)Studies of feasibility After understanding the product functions， operational conditions， manufacturing constraints and key technologies， go on to uncover existing solutions to some similar problems so as to clarify the design tasks， understand the needs， present the major functional parameters and evaluate design tasks， proposal of design aims， and feasibility analysis． (2) Conceptual design of configuration According to the design of tasks and functional parameter， designs need to extensively search for various feasible configurations and alternatives． For convenience， usually， the system can be analyzed prehensively by deposing it into power sources， transmission and work mechanisms． A great effort needs to be devoted to the analysis and synthesis of these different parts． For example， the power source may be selected from motor， engine and turbine． Each power source may have a range of power and kinematical parameters ． Similarly, power trains may have numerous options available， e． g． belts， chains， gears， worm gears and many other drives． Obviously selecting an appropriate configuration would guarantee the Success of the whole design and the quality of the products． To make a best possible decision， an iterative process is normally required to select， analyze， pare and evaluate different configurations． At this stage， the goals involve sketching of configuration， determination of kinematical mechanisms， and evaluation of functional parameter(power and kinematics)． (3)Detailed technical design Based on the design of configuration and parameters， a number of assembly and ponent drawings will be pleted to reflect the detailed design including kinematics， power， strength， stiffness， dynamics， sta。