【正文】 rez G Selfaffine cracks in a brittle porous material Theor ApplFract Mech 44 187191 2020 [17] Yates B W well D Chen S Truax B The Canadian Light Source Optical Metrology Facility NuclInstr and Meth A 582 146148 2020 [18] Ashkar F Mahdi S Fitting the loglogistic distribution by generalized moments J Hydrology 328 694703 2020 附 錄 機(jī)械設(shè)備一覽表 序號(hào) 機(jī)械設(shè)備名稱 型號(hào) 生產(chǎn)能力 th 數(shù)量 備注 1 2 3 4 5 6 7 8 9 10 11 1213 14 15 鄂式破碎機(jī) 鄂式破碎機(jī) 錘式破碎機(jī) 單轉(zhuǎn)式籠磨機(jī) 振動(dòng)篩 六角篩 電子稱 QH 混合機(jī) QH 混合機(jī) 皮帶輸送機(jī) 斗式提升機(jī)帶式除塵器 PEF125 250 PEF250500 PCB600400 直徑 1350 2020900 Φ 11002 000 TCS QH750 QH375 帶速 1315 D250 合成纖維 14 520 415 58126 10205 2 2 1 1 1 1 2 9 1 1 0160 50500 ㎏ 18 045 15m 寬 m3h 6 17～ 436 th 380 ㎏盤 15 1 1 外文資料翻譯 Composites in Aerospace Applications By Adam Quilter Head of Strength Analysis Group ESDU International an IHS pany Introduction The aerospace industry and manufacturers unrelenting passion to enhance the performance of mercial and military aircraft is constantly driving the development of improved high performance structural materials Composite materials are one such class of materials that play a significant role in current and future aerospace ponents Composite materials are particularly attractive to aviation and aerospace applications because of their exceptional strength and stiffnesstodensity ratios and superior physical properties A posite material typically consists of relatively strong stiff fibres in a tough resin matrix Wood and bone are natural posite materials wood consists of cellulose fibres in a lignin matrix and bone consists of hydroxyapatite particles in a collagen matrix Better known manmade posite materials used in the aerospace and other industries are carbon and glassfibrereinforced plastic CFRP and GFRP respectively which consist of carbon and glass fibres both of which are stiff and strong for their density but brittle in a polymer matrix which is tough but neither particularly stiff nor strong Very simplistically by bining materials with plementary properties in this way a posite material with most or all of the benefits high strength stiffness toughness and low density is obtained with few or none of the weaknesses of the individual ponent materials CFRP and GFRP are fibrous posite materials another category of posite materials is particulate posites Metal matrix posites MMC that are currently being developed for the aviation and aerospace industry are examples of particulate posites and consist usually of nonmetallic particles in a metallic matrix for instance silicon carbide particles bined with aluminium alloy Probably the single most important difference between fibrous and particulate posites and indeed between fibrous posites and conventional metallic materials relates to directionality of properties Particulate posites and conventional metallic materials are isotropic ie their properties strength stiffness etc are the same in all directions fibrous posites are anisotropic ie their properties vary depending on the direction of the load with respect to the orientation of the fibres Imagine a small sheet of balsa wood it is much easier to bend and break it along a line parallel to the fibres than perpendicular to the fibres This anisotropy is overe by stacking layers each often only fractions of a millimetre thick on top of one another with the fibres oriented at different angles to form a laminate Except in very special cases the laminate will still be anisotropic but the variation in properties with respect to direction will be less extreme In most aerospace applications this approach is taken a stage further and the differently oriented layers anything from a very few to several hundred in number are stacked in a specific sequence to tailor the properties of the laminate to best withstand the loads to which it will be subjected This way material and therefore weight can be saved which is a factor of prime importance in the aviation and aerospace industry Another advantage of posite materials is that generally speaking they can be formed into more plex shapes than their metallic counterparts This not only reduces the number of parts making up a given ponent but also reduces the need for fasteners and joints the advantages of which are twofold fasteners and joints may be the weak points of a ponent a bolt needs a hole which is a stress concentration and therefore a potential crackinitiation site and fewer fasteners and joints can mean a shorter assembly time Shorter assembly times however need to be offset against the greater time likely to be needed to fabricate the ponent in the first place To produce a posite ponent the individual layers which are often preimpregnated prepreg with the resin matrix are cut to their required shapes which are all likely to be different to a greater or lesser extent and then stacked in the specified sequence over a former the former is a solid or framed structure used to keep the uncured layers in the required shape prior to and during the curing process This assembly is then subjected to a sequence of temeratures and pressures tocure the material The product is then checked thoroughly to ensure both that dimensional tolerances are met and that the curing process has been successful bubbles or voids in t