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附：外文翻译
外文原文：
Fundamｅｎtals of　Meｃｈanｉcａl Design
Mｅchanicaｌ　deｓｉｇn ｍeanｓ the desiｇn ｏf thｉngs aｎd ｓystｅｍs　of　a mechanｉｃal naturｅ—mａchｉｎes， ｐroductｓ，　structurｅs， deｖiceｓ,　and ｉｎstrｕmeｎｔs。 Ｆoｒ the mｏｓt parｔ　mechaｎicａl design　utiｌizes mａｔhematics， tｈｅ　matｅｒiａlｓ sｃieｎcｅs, anｄ ｔhｅ engｉnｅｅrｉng－mechａnics　sciences。
Ｔhe totａｌ　ｄesign prｏcess is of ｉntereｓt　ｔo ｕｓ。 How doeｓ iｔ begin？ Does the　eｎgｉｎeｅr ｓimpｌy sit　doｗn aｔ hiｓ desｋ wｉｔh a blaｎk ｓhｅet　of paper? And， ａs　he　ｊots down　soｍe iｄeas, wｈaｔ　happens next? What factors ｉnfｌｕence or ｃoｎtｒol　the deｃisｉons　which have to　be mａdｅ? Finaｌly， then， how ｄoes　this desiｇn prｏcess ｅnd？
Soｍｅtｉmeｓ， but　not ａlways， dｅsiｇｎ ｂegｉnｓ when an　engineer　recogniｚes a need ａｎd decｉdes　to do sometｈiｎｇ ａbout　ｉt。 Ｒecｏgｎiｔion of　thｅ ｎｅed ａｎｄ phrasｉng iｔ in　ｓｏ mａny words oｆｔen ｃonｓtｉtute　a highly ｃｒeative acｔ ｂｅcause ｔhe need mａy be only ａ vague discoｎtent, ａ　feeｌing oｆ uneasｉness， of　ａ senｓiｎg　ｔhat someｔｈing　ｉs　nｏt rｉght.
The need is ｕｓually not ｅvident　ａt ａll．　Foｒ　example,　thｅ ｎeｅd to do something about　ａ food－paｃｋagｉng　ｍachine may be indicated by the　noiｓe levｅl, bｙ　the vaｒｉａｔiｏns ｉn packagｅ　ｗeｉghｔ, anｄ by ｓｌｉghｔ ｂut perceptｉｂｌe vaｒiaｔioｎs　in thｅ qｕａｌity of ｔhe　pａｃkaｇｉng or　ｗrａp.
Thｅrｅ　is ａ dｉｓtiｎct　differencｅ beｔween ｔｈe sｔａteｍeｎt oｆ　the neｅd aｎｄ　thｅ iｄentificａtioｎ of the ｐrｏblｅm. Which followｓ　this ｓtatement?　Tｈe pｒoblｅm　is morｅ ｓpecifiｃ。 Iｆ　tｈe　neeｄ is for cｌeaner air,　the prｏblem　miｇht ｂe thaｔ　oｆ rｅｄucｉｎg the dｕｓt discｈaｒge ｆｒom ｐowｅr—pｌａnt stacks， or reducｉng　the ｑuanｔity ｏf irritａnts fｒoｍ aｕtoｍｏtive eｘhausｔｓ．
Deｆinition　of thｅ ｐroblem mｕｓt　inclｕde all tｈe　specificatiｏns for thｅ thing ｔｈat is ｔｏ　be　desigｎed。　The specificａtions are ｔhe iｎpuｔ and　oｕtｐut qｕantｉtiｅs， the　chａｒaｃtｅｒistics　ｏｆ　tｈe sｐace the thｉｎｇ must ocｃuｐy aｎｄ　all tｈe ｌｉmitaｔiｏns oｎ these quａｎtitiｅs. We can ｒegarｄ the thｉng to be dｅsigｎed aｓ ｓoｍｅthｉnｇ ｉn a bｌack box。 Ｉｎ tｈiｓ caｓｅ ｗｅ　ｍｕｓｔ speciｆy ｔhe inpｕｔｓ　aｎd ｏuｔpｕts　ｏf ｔｈe box　toｇeｔheｒ with thｅir　cｈarａctｅｒistics and ｌiｍｉtatioｎs.