机械设计英文文献和中文翻译(2)
Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted.
Basically, there are only three means of communication available to us. These are the written, the oral. and the graphical forms. Therefore the successful engineer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these forms is severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is!
The competent engineer should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great deal to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In the final analysis, the real failure would lie in deciding not to make the presentation at all.
A new machine is born because there is a real or imagined need for it. It evolves from someone's conception of a device with which to accomplish a particular purpose. From the conception follows a study of the arrangement of the parts, the location and length of links ( which may include a kinematic study of the linkage ), the places for gears, bolts, springs, cams, and other elements of machines. With all ideas subject to change and improvement, several solutions may be and usually are found, the seemingly best one being chosen.
The actual practice of designing is applying a combination of scientific principles and a knowing judgment based on experience. It is seldom that a design problem has only one right answer, a situation that is seemingly best one being chosen.
The actual practice of designing is applying a combination of scientific principles and a knowing judgment based on experience. It is seldom that a design problem has only one right answer, a situation that is often annoying to the beginner in machine design.
Design problems usually have more than one answer. Given a general statement of a design problem, such as design a machine to wash clothes in the home automatically, and there will be as many different answers as there are design teams--as attested by the number of washing machines on the market.
Engineering practice usually requires compromises. Competition may require a reluctant decision contrary to one's best engineering judgment; production difficulties may force a change of design; etc.
A good designer needs many attributes, for example:
(1) A good background in strength of materials, so that the stress analyses are sound. The parts of the machine should have adequate strength and rigidity, or other characteristics as needed.
(2) A good acquaintance with the properties of materials used in machines.
(3) A familiarity with the major characteristics and economics of various manufacturing processes, because the parts that make up the machine must be manufactured at a competitive cost. It happens that a design that is economic for one manufacturing plant may not be so for another. For example, a plant with a well-developed welding department but no foundry might find that welding is the most economic fabricating method in a particular situation; whereas another plant faced with the same problem might decide upon casting because they have a foundry (and may or may not have a welding department ).