發信人: aerogirl (aerogirl)    看板: Aero
日期: Fri Dec 25 14:30:09 1998
標題: Aero  Materials

Hi! Happy New Year!!!
好不容易考完試囉  現在是聖誕假期 所以有時間post文章囉

小妹是念材料的  懂的就只有材料的東西
而這板好像大多是有關mechanical的資料較多  希望你們也喜歡航太材料囉

為什麼現今很多大公司都對航太材料有興趣呢
為什麼他們很重視複合材料(composites)呢

複合材料的優點在於它集和個種材料的優點
The main reason that composites are attractive to aerospace designers is because 
they offer less weight and better temperature characteristics.
一架輕的飛機可以節省很多油  因此可以省錢
另外 省下的重量代表可以多載幾名乘客 嘿嘿  那代表賺更多錢阿
大家或許覺得這沒什麼  但一架飛機機乎是不停的飛上幾十年的 加起來可就不少錢囉 

The most common composites used in aerospace are CFRP (Glassfiber Reinforced Fiber Plastics), graphite-epoxy composites and Kevlar.  After CFRP was first used 
for the A310-300 airliner in 1985, it became the largest composite part to enter production on an airliner.  CFRP are also used in many parts of an airliner 
including the radome, the pylon fairings, wing cover panels, fin leading edge, and the fuselage.  Airbus Industrie has done some research and found that CFRP 
fuselage and wings provide a 35% weight saving.  A reduction of 1kg saves about US$1,000 over the life of an aircraft.

Graphite-epoxy composites make the Bell-Boeing V-22 Osprey helicopter, light and strong enough for its job and also reduce the manufacturing cost.  A 
graphite-epoxy composite wing of a V-22 weighs 1,000 1b less than a metal one, and it also reduces a payload by 12%.  Composite wings, fuselage, and 
proprotors are 25% lighter in total than a comparable airframe.

飛幾十年 怎知道何時要維修呢 
現今科技發達 總不可能測試幾架飛機幾十年之後才說 何時該換那些零件
何時該換做保養  太久也太離譜囉
以材料的角度來說  材料的chemical breakdown and aging可決定它的壽命
一般材料工程師會做Time-Temperature Superposition 以溫度來推測Time
人類目前尚無法控制時間 比較上控制溫度就容易多了
很多人相信Time and temperature are exchangeable.  到目前為止Time-Temperature Superposition hasn't failed yet.  很多維修保養及飛機壽命的時間就這麼推出來囉

很多人都忽略到航太材料的重要性
到底有多重要呢
例如 一個油槽要承受高溫 Polymers are impossible.  Some metals are possible. (i.e. Titanium  However, it's expensive and heavy comparing to others.)  Ceramics 
are able to handle really high temperatures, but they are brittle.  Even a very tiny crack will cause explosion. 
Well…..I will tell you guys more examples next time.

Sorry!  My Chinese is really bad.  Hopefully, you guys can understand my Chinese.  If not, sorry about it.

P.S. Typing in Chinese is like torturing me. 
 

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* Origin: 國立中山大學 Formosa BBS * From: 168.95.4.18 [已通過認證]
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