可靠度的統(tǒng)計分析-文庫吧資料
2025-06-30 05:51本頁面
【正文】 ，理論上均須由此等隨操作時間而產(chǎn)生變化之隨機設(shè)計變量著手，進行可靠度分析。 ! g(X)0 f(X)dX ()上述討論是基于在特定環(huán)境(Environment。 ! g(X)0 f(X)dX ()產(chǎn)品可靠度R代表產(chǎn)品安全狀態(tài)的機率，其值應(yīng)等于安全區(qū)域的相對應(yīng)體積分R 186。若設(shè)計變量X向量的聯(lián)合機率密度函數(shù)(Joint Probability Density Function)為f(X)，則其失效機率為， F 186。由幾何觀點，臨界狀態(tài)方程式g(X)= 0為一n維曲面，該曲面稱之為”失效面(Failure Surface)”?！?g(X) = 0代表產(chǎn)品之供需處于平衡的臨界狀態(tài)(強度等于應(yīng)力)，在此狀態(tài)之性能函數(shù)稱為臨界狀態(tài)方程式(Limit State Equation)。一般化之定量可靠度為，R = Pr (強度應(yīng)力|環(huán)境)一般以描述產(chǎn)品強度與使用時所承受之應(yīng)力的關(guān)系式說明之，此關(guān)系稱之為產(chǎn)品的性能(績效)函數(shù)(Performance Function)。 定量可靠度描述 在進行與產(chǎn)品可靠度有關(guān)之溝通協(xié)調(diào)時，采標(biāo)準(zhǔn)化與數(shù)量化之方法，以確保所有敘述均適切、精確、一致且清楚不模糊。時間由產(chǎn)品的壽命周期(Life Cycle)決定之，如壽命周期的全部、任務(wù)階段(Mission Phase)。可靠度為產(chǎn)品出廠后的時間質(zhì)量。產(chǎn)品訂約之初即應(yīng)就產(chǎn)品之失效現(xiàn)象予以明確。故障= 失效 = 喪失功(機)能。在數(shù)理統(tǒng)計上，可靠度是條件機率問題，特別強調(diào)啟用瞬間(初始條件)及操作過程的(環(huán)境)條件?！?『成功機率』，相對產(chǎn)品可成功運作，便是產(chǎn)品發(fā)生失效(故障)(Failure)。組成可靠度四要素『功能』、『使用條件』、『時間』、『成功機率』。三者之關(guān)系，ondownt1t2t3tr1tr2tr3 Availability = (t1 + t2 + t3 )/T = (t1 + t2 + t3 )/[(t1 + t2 + t3 )+ (tr1 + tr2 + tr3 )]= (t1 + t2 + t3 )/r/[(t1 + t2 + t3 )/r+ (tr1 + tr2 + tr3 )/r]| r = 3 = MTBF/(MTBF+MTTR)Quality versus Reliability There is a fundamental difference between quality and reliability. Quality is the goodness of a product as it leaves the factoryat zero time. Reliability has two additional dimensionstime and stress. Time refers to product life. Stress refers to various stress or environmental factors, such as temperature, vibration, humidity, etc., that interact with one another, synergizing and accelerating field failures. So, even though quality reliability are terms used synonymously, reliability is more importantto the customers, to warranty costs, to product recalls, and to liability law suits. (Ref. World Class Quality) 產(chǎn)品可靠度的描述 定性可靠度描述 1952年美國國防部所成立之電子裝備可靠度顧問小組(Advisory Group on the Reliability of Electronic Equipment?！?維修度(Ma
范文總結(jié)相關(guān)推薦
鄂ICP備17016276號-1