=1.18，=1.25.許用接觸應(yīng)力===798Mpa===690MPa驗(yàn)算==189.8=417.56MPa<計(jì)算結(jié)果表明，接觸疲勞強(qiáng)度較為合適，齒輪尺寸無(wú)需調(diào)整。分度圓直徑：d=14=266mm，d=14=8683.33同步帶的傳送和計(jì)算1、設(shè)計(jì)功率由《機(jī)械設(shè)計(jì)手冊(cè)》22.1-50查的，是同步帶傳動(dòng)的工作情況系數(shù)，2、選定帶型和節(jié)距根據(jù)和轉(zhuǎn)速，由《機(jī)械設(shè)計(jì)手冊(cè)》圖22.1-12確定為XH型，節(jié)距mm3、小帶輪齒數(shù)根據(jù)帶型XH和帶輪轉(zhuǎn)速，由《機(jī)械設(shè)計(jì)手冊(cè)》表22.1-5查的小帶輪的最小齒數(shù)=24此處取=254、小帶輪節(jié)圓直徑由表22.1-56查的外徑5、大帶輪齒數(shù)6、大帶輪節(jié)圓直徑7、帶速9.25m/s8、初定軸間距取9、帶長(zhǎng)及其齒數(shù)==1908mm由《機(jī)械設(shè)計(jì)手冊(cè)》表22.1-47查的應(yīng)選用帶長(zhǎng)代號(hào)為770的XH型的同步帶，其節(jié)線長(zhǎng)，節(jié)線長(zhǎng)上的齒數(shù)。10、實(shí)際軸間距a此結(jié)構(gòu)的軸間距可調(diào)整11、小帶輪嚙合齒數(shù)1112、基本額定功率由《機(jī)械設(shè)計(jì)手冊(cè)》表22.1-53查的=36.28KW13、所需帶寬由《機(jī)械設(shè)計(jì)手冊(cè)》表22.1-52查的XH=101.6mm，=199.6mm由表22.1-48查的，應(yīng)選帶寬代號(hào)為770的XH型號(hào)14、帶輪結(jié)構(gòu)和尺寸小帶輪：大帶輪：3.34主軸計(jì)算：主軸1的最小直徑計(jì)算：主軸的材料為40，查《機(jī)械設(shè)計(jì)手冊(cè)》得25，,16則155mm主軸2的最小直徑：226.7.取250mm3.35軸的強(qiáng)度校核軸1按扭轉(zhuǎn)強(qiáng)度條件計(jì)算，公式如下;已知?jiǎng)t23.67，則符合要求。軸2按扭轉(zhuǎn)強(qiáng)度條件計(jì)算，已知。公式如下：=17.80mm，則符合要求。3.36主軸上鍵的強(qiáng)度校核根據(jù)主軸的設(shè)計(jì)，鍵所在軸1的直徑為155mm，查《機(jī)械設(shè)計(jì)手冊(cè)》（摘自GB/T1096-2003）選取鍵的尺寸為，普通平鍵連接的強(qiáng)度條件為：，式中d是軸的直徑，l是鍵的工作長(zhǎng)度，h是鍵的高度則，故鍵1的強(qiáng)度滿足要求。，故鍵2的強(qiáng)度滿足要求。3.37摩擦銷的結(jié)構(gòu)設(shè)計(jì)適合摩擦磨損試驗(yàn)測(cè)試儀的測(cè)試球尺寸有1.5毫米、3毫米、6毫米、10毫米(均為直徑)?？梢詾椴煌睆降哪Σ燎蚺鋫洳煌膬?nèi)徑夾持器。夾持器為中空結(jié)構(gòu)，后面有螺紋，只需將測(cè)試球從夾具的后端放入并用配套的零件旋緊即可。3.38試樣夾持器的設(shè)計(jì)用螺栓將試樣夾持器固定在齒條上，使之隨齒條一起做往復(fù)運(yùn)動(dòng)。在試樣夾持器的下面加上一墊片，直徑大小和試樣夾持器相當(dāng)，但厚度可調(diào)，裝卸方便，是這個(gè)夾持器更加通用化。磨損量的測(cè)量4.1常用的磨損量的測(cè)量方法機(jī)械零件的磨損量通常用磨損件的質(zhì)量，體積減少量或者磨去厚度來(lái)表示。磨損質(zhì)量和磨損體積是整個(gè)磨損件表面質(zhì)量和體積減少量的總和，而磨損厚度能夠反映磨損沿表面的分布情況。常用的磨損量測(cè)量方法如下：1稱量法通常利用天平稱出磨損前后的試件質(zhì)量的變化，因此也叫失重法。對(duì)所用天平的精密度要求取決于磨損量的數(shù)量級(jí)。由于測(cè)量范圍的限制，稱量法僅適用于較小的試件。2測(cè)量法使用千分尺、測(cè)長(zhǎng)儀和萬(wàn)能工具顯微鏡等測(cè)量試件在實(shí)驗(yàn)前后磨損表面的法向尺寸的變化或者磨損表面與某基準(zhǔn)面距離的變化。3表面輪廓或粗糙度法用表面輪廓儀可以直接測(cè)量磨損前后表面輪廓的變化來(lái)確定磨損量，即磨損厚度不超過(guò)表面粗糙峰高度的磨損。它實(shí)際反映了磨損表面的微觀變化，也可以直接從其粗糙度等級(jí)的變化，特別是磨損前后加工痕跡的減少來(lái)判斷磨損的程度。表面輪廓法可以記錄表面輪廓在磨損過(guò)程中的變化和磨損分布，但是輪廓法測(cè)量手續(xù)復(fù)雜，被測(cè)零件的形狀和尺寸受量程范圍限制。4壓痕或切槽法人為的在摩擦表面上壓痕或者切槽作為測(cè)量基準(zhǔn)，用基準(zhǔn)尺寸沿深度變化的規(guī)律度量磨損厚度。如果在摩擦表面上不同部位布置基準(zhǔn)，還可以測(cè)量磨損表面的分布。但這種方法對(duì)試樣表面有損害，不利于研究摩擦磨損過(guò)程中表層組織結(jié)構(gòu)的變化。5沉淀法或化學(xué)分析法沉淀法是將潤(rùn)滑油中所含的磨屑經(jīng)過(guò)過(guò)濾或者沉淀分離出來(lái)，再由稱重法測(cè)量磨屑質(zhì)量。也可以采用定量化學(xué)分析的方法測(cè)量潤(rùn)滑油中所含磨屑的組成和質(zhì)量，這不僅可以測(cè)量各種元素的質(zhì)量，還可以根據(jù)材料使用情況來(lái)判斷磨損的部位。4.2摩擦系數(shù)測(cè)試部分如圖作用在試件的載荷上（正壓力)P由法碼重力產(chǎn)生，作用在摩擦副間的摩擦力為F，若兩個(gè)試件間的摩擦系數(shù)為，則有。故只需要預(yù)先確定砝碼的重力，在測(cè)出傳感器受力大小，即可計(jì)算出摩擦系數(shù)P正壓力磨頭下試件F摩擦力正壓力由人工根據(jù)需要通過(guò)法碼施加，是一個(gè)穩(wěn)定值。摩擦力是兩個(gè)相對(duì)運(yùn)動(dòng)產(chǎn)生的，是一個(gè)變化值，可通過(guò)測(cè)量求得。小結(jié)摩擦磨損試驗(yàn)機(jī)是進(jìn)行摩擦磨損試驗(yàn)的有效設(shè)備，廣泛運(yùn)用于對(duì)各種高速刀具的摩擦磨損性能進(jìn)行測(cè)試和評(píng)價(jià)，是高速切削和新型刀具材料研制和應(yīng)用的必要設(shè)備。因此本文對(duì)往復(fù)式摩擦磨損試驗(yàn)機(jī)的原理和結(jié)構(gòu)進(jìn)行介紹，給出了試驗(yàn)機(jī)的基本參數(shù)，并對(duì)試驗(yàn)機(jī)的機(jī)械結(jié)構(gòu)部分進(jìn)行了相關(guān)設(shè)計(jì)和計(jì)算，為試驗(yàn)機(jī)的設(shè)計(jì)和實(shí)際制作提供了一定的依據(jù)和參考。該設(shè)計(jì)在滿足設(shè)計(jì)要求的前提下，力求結(jié)構(gòu)簡(jiǎn)單，制造成本低廉，沒(méi)有一味的追求高精度，適合進(jìn)行實(shí)際的生產(chǎn)。設(shè)計(jì)中采用了較為簡(jiǎn)單的方法實(shí)現(xiàn)了相同的功能。該設(shè)計(jì)只是針對(duì)摩擦磨損試驗(yàn)機(jī)的機(jī)械結(jié)構(gòu)部分進(jìn)行了相關(guān)的設(shè)計(jì)計(jì)算和仿真，而電氣控制系統(tǒng)和檢測(cè)系統(tǒng)還需要進(jìn)一步的補(bǔ)充。通過(guò)老師的講解和查閱資料讓我有了初步的認(rèn)識(shí)。在畢業(yè)設(shè)計(jì)中期階段主要是完成自己部分機(jī)構(gòu)和零件的設(shè)計(jì)。在翻閱書本的過(guò)程中，此過(guò)程的應(yīng)用到了我在大三時(shí)所學(xué)的機(jī)械設(shè)計(jì)和互換性等課程。從前我對(duì)機(jī)械的認(rèn)識(shí)很是膚淺，只是會(huì)做一些課程設(shè)計(jì)。卻沒(méi)有把整個(gè)機(jī)械課程聯(lián)系起來(lái)，其實(shí)各個(gè)專業(yè)課都是有相互聯(lián)系的，而這些基礎(chǔ)課也不容忽視，它們是我們完成設(shè)計(jì)的基礎(chǔ)，更是進(jìn)一步在機(jī)械領(lǐng)域發(fā)展的前提。在CAD圖形繪制過(guò)程中，我用到了機(jī)械制圖這門課程。同時(shí)，我也掌握了一門畫圖軟件。此次畢業(yè)設(shè)計(jì)真是讓我收獲頗豐，不僅讓我對(duì)專業(yè)課有了新的認(rèn)識(shí)而且得到了許多書本上沒(méi)有的東西。我一直在思考的問(wèn)題，如何學(xué)好我的專業(yè)，并將它自如的應(yīng)用到以后的工作中，似乎在本次畢業(yè)設(shè)計(jì)中有了答案。致謝大學(xué)四年學(xué)習(xí)時(shí)光已經(jīng)接近尾聲，在此我想對(duì)我的母校，我的父母、親人們，我的老師和同學(xué)們表達(dá)我由衷的謝意。感謝我的家人對(duì)我大學(xué)四年學(xué)習(xí)的默默支持；感謝我的母校太原理工大學(xué)給了我在大學(xué)四年深造的機(jī)會(huì)，讓我能繼續(xù)學(xué)習(xí)和提高；感謝老師和同學(xué)們四年來(lái)的關(guān)心和鼓勵(lì)。老師們課堂上的激情洋溢，課堂下的諄諄教誨；同學(xué)們?cè)趯W(xué)習(xí)中的認(rèn)真熱情，生活上的熱心主動(dòng)，所有這些都讓我的四年充滿了感動(dòng)。這次畢業(yè)論文設(shè)計(jì)我得到了很多老師和同學(xué)的幫助，其中我的論文指導(dǎo)老師宋金鵬老師對(duì)我的關(guān)心和支持尤為重要。每次遇到難題，我最先做的就是向老師尋求幫助，而老師每次不管忙或閑，總會(huì)抽空來(lái)找我面談，然后一起商量解決的辦法。老師平日里工作繁多，但我做畢業(yè)設(shè)計(jì)的每個(gè)階段，從選題到查閱資料，論文提綱的確定，中期論文的修改，后期論文格式調(diào)整等各個(gè)環(huán)節(jié)中都給予了我悉心的指導(dǎo)。這幾個(gè)月以來(lái)，老師不僅在學(xué)業(yè)上給我以精心指導(dǎo)，同時(shí)還在思想給我以無(wú)微不至的關(guān)懷，在此謹(jǐn)向老師致以誠(chéng)摯的謝意和崇高的敬意。感謝在整個(gè)畢業(yè)設(shè)計(jì)期間和我密切合作的同學(xué)，和曾經(jīng)在各個(gè)方面給予過(guò)我?guī)椭幕锇閭儯诖?，我再一次真誠(chéng)地向幫助過(guò)我的老師和同學(xué)表示感謝！參考文獻(xiàn)[1]張嗣偉.摩擦學(xué)的進(jìn)展與展望[J].摩擦學(xué)學(xué)報(bào)，2004，1:44-45.對(duì)摩擦學(xué)近10多年來(lái)在潤(rùn)滑與潤(rùn)滑劑和摩擦與磨損這兩個(gè)方面的進(jìn)展作了綜合介紹與評(píng)述，指出最引人注目的是采用掃描隧道顯微鏡、原子力顯微鏡和超薄膜干涉儀等先進(jìn)儀器設(shè)備對(duì)邊界潤(rùn)滑和邊界膜進(jìn)行原位研究，以及納米摩擦學(xué)、陶瓷摩擦學(xué)、空間摩擦學(xué)、核反應(yīng)系統(tǒng)摩擦學(xué)、微觀摩擦學(xué)和表面工程等的發(fā)展與各種新型摩擦學(xué)材料的開(kāi)發(fā)。同時(shí)，還對(duì)本世紀(jì)末和下世紀(jì)初摩擦學(xué)的發(fā)展前景作了展望，認(rèn)為在摩擦學(xué)設(shè)計(jì)、新的摩擦學(xué)系統(tǒng)、特殊的摩擦學(xué)材料、新的表面技術(shù)和用于極端工況或特殊工況下的潤(rùn)滑劑等方面都將取得新的進(jìn)展，并且結(jié)合國(guó)內(nèi)實(shí)際，提出了加速我國(guó)摩擦學(xué)學(xué)科發(fā)展和推動(dòng)我國(guó)摩擦學(xué)工業(yè)應(yīng)用的建議。[2]陳海燕，王成國(guó).分形理論及其在摩擦學(xué)研究中的應(yīng)用[J].材料導(dǎo)報(bào)，2002，12:10-11.介紹了分形的概念以及分形維數(shù)的計(jì)算方法,重點(diǎn)討論了分形理論在摩擦學(xué)研究,如摩擦表面分析、摩擦磨損問(wèn)題研究和滑動(dòng)摩擦溫度分布的分形模型等方面的應(yīng)用。

[3]陳國(guó)安，葛世榮，王軍祥.分析理論在摩擦學(xué)研究中的應(yīng)用[J].摩擦學(xué)學(xué)報(bào)，2008，5（2）：15-18.采用尺度獨(dú)立的分形參數(shù)可使粗糙表面和磨屑形貌的表征簡(jiǎn)單明了，并使表征具有唯一性，易于識(shí)別；基于分形參數(shù)所建立的摩擦學(xué)研究模型的預(yù)測(cè)結(jié)果可望不受測(cè)量?jī)x器分辨率和取樣長(zhǎng)度的影響，因而比傳統(tǒng)的基于統(tǒng)計(jì)分析的模型更為合理和有效．綜述了分形幾何在粗糙表面的表征、接觸、磨損預(yù)測(cè)和摩擦溫度分布以及磨屑定量分析等方面的應(yīng)用現(xiàn)狀和發(fā)展，指出了用分形理論研究摩擦學(xué)問(wèn)題時(shí)應(yīng)注意的著重點(diǎn)[4]戴振東，薛群基，王珉.試論摩擦學(xué)研究中的科學(xué)方法問(wèn)題[J].南京航天航空大學(xué)報(bào)，2008，12:55-58.摩擦學(xué)是工程先導(dǎo)性的學(xué)科高度交叉綜合的前沿研究領(lǐng)域，是尚未成熟和最具活力的學(xué)科之一，它具有用戶要求多樣的特點(diǎn)。近年來(lái)的大量實(shí)驗(yàn)結(jié)果對(duì)摩擦學(xué)理論產(chǎn)生了巨大的沖擊。為迎接挑戰(zhàn)并更好地指導(dǎo)工業(yè)設(shè)計(jì)，須重新探討摩擦學(xué)的研究方法，表征量的選擇及其思想方法。作者認(rèn)為在繼續(xù)開(kāi)展摩擦學(xué)實(shí)驗(yàn)研究的同時(shí)，須大力推進(jìn)理論研究，非平衡態(tài)熱力學(xué)可做為該研究的基礎(chǔ)，熵可用作為表征量。研究中應(yīng)特別重視過(guò)程非線性、可逆性和混沌性，并積極探討摩擦自組織結(jié)構(gòu)的形成條件及其工業(yè)應(yīng)用的可能。[5]謝友柏，摩擦學(xué)的三個(gè)公理[J].摩擦學(xué)學(xué)報(bào)，2003，3:15-16.討論了摩擦學(xué)發(fā)展中存在的問(wèn)題.指出作為一門非常重要的應(yīng)用基礎(chǔ)學(xué)科,摩擦學(xué)在繼承摩擦、磨損和潤(rùn)滑幾千年來(lái)積累起來(lái)的理論成果和應(yīng)用成果的基礎(chǔ)上,沒(méi)有建立與摩擦、磨損和潤(rùn)滑相比有所發(fā)展且與自身的定義和性質(zhì)相適應(yīng)并可以支持自身獨(dú)立發(fā)展的理論體系和方法體系.提出摩擦學(xué)中存在3個(gè)基本公理:即第一公理——摩擦學(xué)行為是系統(tǒng)依賴的;第二公理——摩擦學(xué)元素的特性是時(shí)間依賴的;第三公理——摩擦學(xué)行為是多個(gè)學(xué)科行為之間強(qiáng)耦合的結(jié)果.由這些公理可以推導(dǎo)出一系列定理和相應(yīng)的系.同時(shí)還討論了用系統(tǒng)的狀態(tài)方程和輸出方程描述含有摩擦副的系統(tǒng)的特性的方法,并給出了應(yīng)用舉例[6]桂長(zhǎng)林，沈健.摩擦磨損試驗(yàn)機(jī)設(shè)計(jì)的基礎(chǔ)Ⅱ.固體潤(rùn)滑[J]，2000，1:5-8.本講介紹采用設(shè)計(jì)方法學(xué)的方法對(duì)摩擦磨損試驗(yàn)機(jī)設(shè)計(jì)進(jìn)行研究的結(jié)果,建立了摩擦磨損試驗(yàn)機(jī)的要求明細(xì)表,功能結(jié)構(gòu)圖、設(shè)計(jì)模幅箱和方案評(píng)價(jià)目標(biāo)樹。根據(jù)本講所闡述的方法,既可使摩擦磨損試驗(yàn)機(jī)的設(shè)計(jì)程序和方案評(píng)價(jià)建立在一套比較科學(xué)的和行之有效的方法上,又能作為建立摩擦磨損試驗(yàn)機(jī)CAD(計(jì)算機(jī)輔助設(shè)計(jì))系統(tǒng)的基礎(chǔ)。[7]桂長(zhǎng)林，沈健.摩擦磨損試驗(yàn)機(jī)設(shè)計(jì)的基礎(chǔ)Ⅰ.固體潤(rùn)滑，2000，1:9-10.本講提出了一種按摩擦系統(tǒng)的結(jié)構(gòu)和摩擦副的相對(duì)運(yùn)動(dòng)形式對(duì)摩擦磨損試驗(yàn)機(jī)進(jìn)行分類的新方法(這種分類法將摩擦磨損試驗(yàn)機(jī)分為五大類),闡述了摩擦磨損試驗(yàn)的目的和摩擦磨損試驗(yàn)機(jī)為實(shí)現(xiàn)此目的所應(yīng)有的基本系統(tǒng),分析了基本系統(tǒng)中各組成單元的每個(gè)要素在摩擦磨損試驗(yàn)機(jī)中的特殊性,最后還就摩擦磨損試驗(yàn)機(jī)的發(fā)展方向作了簡(jiǎn)要的探討。

[8]桂長(zhǎng)林，沈健.摩擦磨損試驗(yàn)機(jī)設(shè)計(jì)的基礎(chǔ)Ⅲ.固體潤(rùn)滑，2000,1;12-15.將設(shè)計(jì)方法學(xué)的一般方法應(yīng)用于摩擦磨損試驗(yàn)機(jī)的設(shè)計(jì),這對(duì)確定設(shè)計(jì)方案是科學(xué)的和行之有效的。本講通過(guò)一個(gè)設(shè)計(jì)實(shí)例說(shuō)明了設(shè)計(jì)方法學(xué)在摩擦磨損試驗(yàn)機(jī)設(shè)計(jì)中的具體應(yīng)用問(wèn)題,并以舉例的形式詳細(xì)地介紹了在方案設(shè)計(jì)階段的各個(gè)主要工作步驟的實(shí)施方法,即建立要求明細(xì)表-功能分析-建立設(shè)計(jì)模幅箱-方案選擇-方案評(píng)價(jià)。其中,關(guān)鍵的是進(jìn)行功能分析、建立設(shè)計(jì)模幅箱和方案評(píng)價(jià)。[9]周楓，邱憲波，袁景淇.摩擦磨損試驗(yàn)機(jī)試驗(yàn)數(shù)據(jù)處理系統(tǒng)的設(shè)計(jì).測(cè)控技術(shù)，2004，4;14-16.介紹了在LabVIEW開(kāi)發(fā)平臺(tái)下,摩擦磨損試驗(yàn)機(jī)數(shù)據(jù)處理系統(tǒng)的設(shè)計(jì)方法,實(shí)現(xiàn)了試驗(yàn)數(shù)據(jù)的實(shí)時(shí)采集、歷史曲線繪制和試驗(yàn)報(bào)告自動(dòng)生成等功能。[10]李建芳，楊世強(qiáng)，沈璟.往復(fù)摩擦磨損試驗(yàn)機(jī)測(cè)試系統(tǒng)的設(shè)計(jì)[J].潤(rùn)滑與密封2008，10:36-39.設(shè)計(jì)了一種可用于模擬和檢測(cè)車輛減振器中導(dǎo)向套-活塞桿摩擦副動(dòng)態(tài)摩擦學(xué)特性的往復(fù)摩擦磨損試驗(yàn)機(jī)測(cè)試系統(tǒng)。在分析減振器往復(fù)運(yùn)動(dòng)的結(jié)構(gòu)和功能的基礎(chǔ)上給出了往復(fù)摩擦磨損試驗(yàn)機(jī)測(cè)試系統(tǒng)的總體模型,建立了往復(fù)運(yùn)動(dòng)的數(shù)學(xué)模型。使用結(jié)果表明,該測(cè)試系統(tǒng)可實(shí)時(shí)檢測(cè)和處理載荷、速度、溫度、摩擦力以及摩擦因數(shù)等參數(shù)信息,并以表格或圖像曲線形式顯示,有利于對(duì)試驗(yàn)材料的摩擦學(xué)特性變化作出實(shí)時(shí)、客觀、量化的評(píng)估。[11]劉毅斌，王毅.摩擦磨損試驗(yàn)機(jī)在線檢測(cè)系統(tǒng)[J].儀器標(biāo)準(zhǔn)化與測(cè)量，2004，6:17-19.現(xiàn)代摩擦學(xué)的試驗(yàn)研究對(duì)摩擦磨損試驗(yàn)機(jī)的測(cè)量系統(tǒng)提出了更高的要求。本文介紹了自行設(shè)計(jì)的強(qiáng)電流摩擦磨損試驗(yàn)機(jī)及其實(shí)時(shí)在線檢測(cè)系統(tǒng),主要包括試驗(yàn)中各參量信號(hào)的獲取,A/D轉(zhuǎn)換,以及對(duì)測(cè)量數(shù)據(jù)誤差的軟件處理方法。

[12]劉永平，龔俊，辛舟，侯運(yùn)豐.往復(fù)式摩擦磨損試驗(yàn)機(jī)及其計(jì)算機(jī)控制系統(tǒng)設(shè)計(jì).儀器儀表學(xué)報(bào)，2010,8:55-58.針對(duì)不同固體材料在不同條件下的摩擦磨損實(shí)驗(yàn)要求,開(kāi)發(fā)設(shè)計(jì)了一種往復(fù)式摩擦磨損試驗(yàn)機(jī),通過(guò)測(cè)量實(shí)驗(yàn)中產(chǎn)生的摩擦力、摩擦系數(shù)和磨損量的變化來(lái)研究材料的摩擦磨損性能。為提高測(cè)試系統(tǒng)的精確性和實(shí)時(shí)性,將計(jì)算機(jī)輔助測(cè)試系統(tǒng)應(yīng)用到摩擦學(xué)試驗(yàn)當(dāng)中,通過(guò)數(shù)據(jù)采集系統(tǒng)和測(cè)試軟件系統(tǒng)完成摩擦磨損數(shù)據(jù)的實(shí)時(shí)動(dòng)態(tài)測(cè)試,從根本上改變了傳統(tǒng)摩擦磨損試驗(yàn)機(jī)的缺點(diǎn)。通過(guò)對(duì)聚四氟乙烯材料的摩擦磨損性能進(jìn)行實(shí)驗(yàn),證明該試驗(yàn)機(jī)性能穩(wěn)定,測(cè)試系統(tǒng)準(zhǔn)確可靠。[13]DenisV.Someproblemsofcomputer-aidedtestingand“interview-liketests”[J].Computers&Education,2008,9:743-756.Computer-basedtesting–isaneffectiveteacher’stool,intendedtooptimizecoursegoalsandassessmenttechniquesinacomparativelyshorttime.However,thisisaccomplishedonlyifwedealwithhigh-qualitytests.Itisstrange,butdespitethe100-yearhistoryofTestingTheory(see,Anastasi,A.,Urbina,S.(1997).Psychologicaltesting.UpperSaddleRiver,NJ:Prentice-Hall)therestillexistsomemisconceptions.Modernwide-spreadsystemsforcomputerbasedcoursemanagementandtestingrevealasetofproblemscorrespondingtocertainfeaturesoftestingmethods.Thisarticleisdevotedtosomeomissionstypicaltoseveralcoursemanagementsystems(e.g.,MoodleandBlackboard).Theseomissionsandthewaysofavoidingthemareshowninasimpletestintendedtoverifystudentknowledge.Wesuggestaspecialtestdescriptionlanguagededicatedtodrawingyourattentiontothemathematicalaspectsoftestquality.Thelanguagecanalsoberealizedincomputersoftware.Weprovideanexampleofsuchsoftwareinthisarticle.[14]WeidongZhang,YiboAi,DesignandControlImplementationofACElectricPowerSteeringSystemTestBench[J],PhysicsProcedia.2012.9:1006–1011UsingACmotorisanimportantdevelopmenttrendofelectricpowersteeringsystem,andinthispaper,weproposedadesignofACelectricpowersteeringsystemtestbench.Thepaperintroducedthebenchstructure,workingprincipleandmaincomponentsselectionfirst,andthengiventheimplementationschemeoftestbench'sthreefunctions:simulationoftheroadresistance,powerassistantcontrolanddataacquisition.Thetestresultsshowedthefeasibilityofthetestbench.[15]H.Fama,b,M.Kontopouloua,b,J.T.Bryanta,c,Methodforfrictionestimationinreciprocatingweartests.Wear.2010(5).6:999-1003AmethodisdescribedbywhichthecoefficientoffrictionwasdeterminedusingalinearreciprocatingweartestingmachinewithsphericalmetalindentersarticulatingonflatUHMWPEsamplesanddeionizedanddistilledwaterlubrication.Acharacteristicperiodicpatterninthefrictionbehaviourwasobserved.Thecoefficientoffrictionwascomputedbycalculatingtheaverageof30pointsaboutthemidpointbetweenreversalsandusingtheaverageofthreecycles.Variabilitybetweentestswasequivalenttothatobtainedbetweenstationsbutwasconsiderablyhigherthanthatobtainedbetweencycles.Thecoefficientoffrictioncouldreliablybeestimatedusingthismethodwithastandarddeviationof0.005.[16]SatishAchantaa.DirkDreesb,Jean-Pierre.CelisaInvestigationoffrictiononhardhomogeneouscoatingsduringreciprocatingtestsatmicro-Newtonnormalforces[J].wear.2009:1066-1069Adhesionisanimportantsurfacephenomenonthatcontrolsmanyphysicaleventsinnatureandtechnology.Theuseofminiaturedeviceslikecombdrives,andcontactMEMSisstilllimitedmostlyduetoadhesiveinteractionsoffreestandingstructuresandfriction,respectively.Moreover,adhesionisanimportantfrictionmechanismatlownormalforces.Inthisstudy,theinterplaybetweensurfaceroughnessandadhesionforcewasstudiedandconsequentlytheirinfluenceonthefrictionforceatlownormalforcesintherangeofμN(yùn)swasexperimentallyinvestigated.Frictionstudieswerecarriedoutthroughaseriesofbi-directionalslidingtestsoncommonlyusedengineeringsurfaceslikesiliconwafer,TiN,andDLCcoatingsusingahighprecisionmodularmicrotribometerinaball-on-planeconfiguration.Thisstudyillustrateshowfrictionoperatesbetweenroughmultiasperitycontactsundercontactstressesbelow125MPa.ForcevolumeimagingwasperformedusinganAFMonsurfaceswithdifferentsurfaceroughness.Forroughsurfaces,alargefluctuationinthelocaladhesionforcewasobservedinsteadofanoveralldecreaseinadhesionasreportedintheliterature.Asthenormalforcedecreases,theinfluenceoftheadhesioncomponentonfrictionincreasesresultinginahighcoefficientoffrictionespeciallyonsiliconandDLCsurfaces.HydrogenatedDLCsurfacescanexhibitlowfrictiononlywhenthesurfaceisrough.Ontheotherhand,TiNcoatingsarelesssensitivetochangesinsurfaceroughness,andexhibitapracticallyconstantcoefficientoffrictionduetoalowadhesivecomponent.TheadhesioncomponentofnormalforcecouldbeestimatedusingJKRadhesionmodel.ThereisacleardependenceofslidingfrictionatlownormalforcesintheμN(yùn)rangeonadhesioneventsobservedatthenano-Nrange.[17]T.Miyajimaa,Y.Tanakaa,Y.Iwaia,Y.Kagoharab,S.Hanedab,S.Takayanagi.Frictionandwearpropertiesoflead-freealuminumalloybearingmaterialwithmolybdenumdisulfidelayerbyareciprocatingtest[J].TribologyInternational.2013,3:17-22FrictionandwearbehaviorofAl–Sn–SialloywithMoS2layerunderlubricatedconditionwasinvestigatedbyareciprocatingfrictiontester.ItbecameclearthattheAl–Sn–SialloywithMoS2layershowedabout70%lowerfrictionandabout1/10lowerweardepthcomparedtotheAl–Sn–Sialloy.ThewornsurfacesoftheAl–Sn–SialloywithMoS2layerwereobservedandanalyzedbyaSEM,aTEMandanEDX.ItindicatedthattheslidingsurfaceofthecounterfacehadlargerareaofMothantheareaofAlwhichwastransferredfromtheAl–Sn–SialloywithMoS2layerbysliding,resultinginlowfrictionandhighwearresistance.附錄一外文原文MethodforfrictionestimationinreciprocatingweartestsH.Fama,b,M.Kontopouloua,b,J.T.Bryanta,c,?aHumanMobilityResearchCentre,Queen’sUniversity,KingstonGeneralHospital,Kingston,ON,,CanadabDepartmentofChemicalEngineering,Queen’sUniversity,Kingston,ON,,CanadacDepartmentofMechanicalandMaterialsEngineering,Queen’sUniversity,Kingston,ON,,CanadaabstractAmethodisdescribedbywhichthecoefficientoffrictionwasdeterminedusingalinearreciprocatingweartestingmachinewithsphericalmetalindentersarticulatingonflatUHMWPEsamplesanddeionizedanddistilledwaterlubrication.Acharacteristicperiodicpatterninthefrictionbehaviourwasobserved.Thecoefficientoffrictionwascomputedbycalculatingtheaverageof30pointsaboutthemidpointbetweenreversalsandusingtheaverageofthreecycles.Variabilitybetweentestswasequivalenttothatobtainedbetweenstationsbutwasconsiderablyhigherthanthatobtainedbetweencycles.Thecoefficientoffrictioncouldreliablybeestimatedusingthismethodwithastandarddeviationof0.005..2011ElsevierB.V.Allrightsreserved1.IntroductionTotalkneereplacementisanorthopaedicsurgicalprocedureusedtoreplacekneejointswithosteoarthritis,rheumatoidarthritisandseveretrauma[1].Thefemoralcomponentistypicallymadeofametalalloysuchascobaltchrome(CoCr)andthetibialcomponentincludesaninserttypicallymadeofUHMWPEonametalbackingmadeofanalloysuchasCoCrortitanium.Wearofthepolymericcomponenthasbeenafocusofstudiesdirectedtowardoptimizingtheperformanceofthesebearings[2–18].Recently,studieshavebeenundertakentoevaluatefrictioninthesesystemsinanattempttounderstandthemechanismsofwear[19–22].Itisrecognizedthatfrictionmeasurementsmayrevealthemodeoflubricationoccurringwithinjointprostheses.Boundaryandhydrodynamicfluidfilmlubricationarethemechanismsknowntotakeplaceinjointreplacements[23].Hydrodynamicfluidfilmlubricationofbearingsurfacesoccurswhenaviscousfilmisgeneratedseparatingthetwosurfaces[24].Thetwosurfacesmustmoverelativetoeachotherwithsufficientvelocityforthehydrodynamicfilmtobegenerated[24].Ifthehydrodynamicpressureisinsufficienttoseparatethesurfaces,thenlubricationwouldprimarilydependonthecomponentsofthefluidthatcouldformboundaryfilms[25].Inboundarylubrication,thesecomponentsadsorbonthebearingsurfacesandaidinminimizingfrictionuponcon-tact.Inmixedlubrication,thesurfacesarepartiallyseparatedbyafluidfilm,andpartiallyincontactattheasperities[24].Lubricantviscosityisacriticaldeterminantinhydrodynamicfluidfilmlubrication,andhenceitisimportanttoconsideritseffectonthefrictionbehaviourofjointprosthesisbearingsurfaces[26].Thisisparticularlyimportantsinceperiprostheticfluid,thefluidthatbathesjointreplacementsinvivo,containsHA(hyaluronicacid)ahighmolecularweightcomponentthatimpartsitwithviscouscharacteristics.Frictionstudieshavebeenconductedtodeterminethelubricationmechanisminwhichdifferentbearingmaterialsofjointreplacementsoperate[27–29].ThisistypicallyperformedbyusingtheStribeckanalysiswherethefrictionfactorisplottedagainsttheSommerfeldnumber[27,28].AdecreaseinthefrictionfactorwithincreaseinSommerfeldnumberisindicativeofmixedlubricationwhileanincreaseinthefrictionfactorwithSommerfeldnumberisindicativeoffluidfilmlubrication[19,28,29].BasedonthisanalysisFlanneryetal.[19]suggestedthatintotalkneereplacementamixedlubricationregimedominates.Whilesimulatortestinghasfocusedonrecreatingtheconditionsofloadingandmotionofjointsinservice[7,9],frictionmeasurementstendtousesimplertestconditionsatconstantspeeds[21].ThisstrategymakesitpossibletodelineatethefactorsinfluencingthelubricationmechanismsassociatedwiththeStribeckcurve.However,wearstudieshaveshownarelationshipbetweenthenatureofsurfacemotion(rolling,sliding,cross-shear,etc.)andwearpatterns[30].Therefore,inordertostudytheroleoflubricationinthisphenomenon,itisnecessarytomeasurefrictionunderthedynamicconditionsassociatedwithjointreplacements.Thepurposeofthisstudywastodetermineamethodforestimatingthefrictioncoefficientinalinearreciprocatingmachineunderkinematicandloadingconditionsrepresentativeofthoseencounteredintotalkneereplacement.Areciprocatingpinondiscfrictionandweartestingmachine(AMTIOrtho-PodTM,AMTITM,Watertown,MA)wasusedwithdeionizedanddistilledwaterlubrication.Aprotocolfordataacquisitionandanalysiswasdesigned,followedbystatisticalanalysisthatquantifiedthevariabilityofthefrictioncoefficientamongdifferentstationsandtests.Thisstudywasdesignedtobeusedasbasisforfutureworkinvolvingdifferentlubricants,testgeometries,andsurfacekinematics.2.Materialsandmethods2.1.InstrumentationAnAMTIOrtho-PodTMsixstationpinondiscfrictionandweartestingmachinewasusedinthisstudy.Differentmotionpathscanbegeneratedbyrotationsofthepinanddisc.Therearetwoassembliesinvolvedinthissetup,thetopheadandthebase.ThetopheadcontainstheCoCrpinactuatorswhilethebasecontainsthediscswheretheUHMWPEspecimensaremounted.Thepinisloadedbyairpressureandrotateswitheitherreciprocatingorrotarymotion.Atotalofsixindividualfluidchannelseachencloseapinanddisc.Awaterbathisusedtoheattheunitusingheattransferpassagesinthebaseplateandupperheadassembly.Acomputercontrolsthemachinetothedesireddiscrotation,pinrotationandverticalload.2.2.TestconditionsA25mmradiushemisphericalCoCrmetalpinwasarticulatedagainstaflatUHMWPEsample(Fig.1).Thisarrangementrepresentsthenon-conforminggeometryarticulationtypicalofatotalkneereplacement[6].Deionizedanddistilledwaterwasusedasthelubricantineachofthechannelsandthetemperatureofeachofthechannelswascontrolledusingawaterbathat37?C.Foreachtest,aloadof210Nwasapplied,resultinginanominalaveragecontactstressof20MPa.TheCoCrpinarticulatedagainsttheUHMWPEsampleinaunidirectionalreciprocalslidingpattern,asshowninFig.1atafrequencyof1Hz.Astraightlinepatternwasdesignedbyprogrammingtherotationsofthepinanddisctotracksevenpointsinboththeforwardandbackwarddirections.MotionstartsatPointAinthepathdepictedinFig.1,continuestoPointBwherethepinstopsandreturnstoPointA.Inaseparatestudy,themotionofthepinwithrespecttothesamplewasmeasuredusinganactiveoptoelectronicmotiontrackingsystem(Optotrack?CertusTM;NDI,Waterloo,Canada).AsshowninFig.2,thepathwasastraightlineintheregionfromy=2mmtoy=8mm;noiseinthex-directionhadarootmeansquareerrorofapproximately175m.ThevelocityprofileshowninFig.3showedanaveragespeedintheforwarddirectionof29.6mm/swithastandarddeviationof4.71andanaveragespeedinthereversedirectionof28.5mm/swithastandarddeviationof4.47.Highstandarddeviationsinthevelocitymeasurementsareexpectedwhennoisypositiondataaredifferentiatedwithrespecttotime;averaging100measurements,forexample,wouldresultinastandarderrorofthismeanthat3.Experimentalprotocol3.1.PinpolishingThreetestswereconductedforeachexperimentalconditionusingthreedifferentstations.TheCoCrpinswerepolishedpriortoeachtesttoamirrorfinish.Threedifferentslurrieswereusedinpolishingthepins:a6microndiamondspray,followedbya0.05micronaluminaslurry,thenfollowedbyacolloidalsilicasolution.Eachslurrywassprayedoncottoncloth-wrappedrotatingdiscs,andthepinswerepolishedagainsttherotatingdiscsfor3–5min.Followingeachpolishing,thepinswerewashedwithsoapwater,rinsedwithwaterandairdried.Thesurfaceofeachpinwasthenexaminedusingalightmicroscopewith4×magnification.3.2.SamplepreparationThesampleswerecutfromcommercialgradeUHMWPEsheet(McMasterCarr,Aurora,OH).Theywerefirstrinsedwithtapwatertoremovebulkcontaminantsandwashedinanultrasoniccleanerinasolutionof1%detergentforfifteenminutes.Theywerethenrinsedwithastreamofdistilledwaterandplacedintheultrasoniccleanerinabeakerofdistilledwaterforfiveminutestorinsethedetergent.Thesamplesweredriedwithlint-freetissueandwerelefttoairdry.EachtestwasconductedwithapolishedpinandanewUHMWPEsample.4.DataacquisThedataacquisitionsystemoftheAMTIOrtho-PodTMcollectsmulti-componentforcedataandfrictioncoefficients.Forcesensorsineachofthethreeverticallegsofthemachinemeasurethreeforcecomponents.ThenineoutputsaresummedtoprovideasinglevalueforeachoftheforcesFx,Fy,andFzwherexandyarethetransversedirectionandzisthenormaldirection.Eachtestwasprogrammedinloopsof10,000repetitions.Thesamplingratewas400datasets/secondfordurationoftenseconds.Datawerecollectedforthelasttencyclesofthefirst10,000cycleloop.AtypicalmeasurementofthetransverseforceandtheverticalloadasafunctionoftimeisshowninFig.4.Thefrictioncoefficientwasdeterminedbytheratioofthefrictionforcetotheverticalload:=(1)ThiscomputationleadstoconsiderablenoiseinthecoefficientduetothenoiseevidentinthecorrespondingforcesignalsshowninFig.4.5.DataanalysisAtypicalfrictioncoefficientoutputfortwocompletecyclesisdepictedinFig.5showingperiodicbehaviourevery400datapoints.ThisbehaviourcorrespondedtothereversalinpinmotionalongthepathandisconsistentwiththatobservedinstudiesbyCostaandHutchings[31].Maximaandminimawereobservedevery200datapointscorrespondingtothestoppoints(PointsAandBinFig.1).Asthepinapproachesastoppoint,thehorizontalforcesensorsdetectelasticforcesresultinginanincreaseinthevalueofthehorizontalforces(FxandFy),leadingtoahighvalueofthecoefficientoffriction.Asthemotionreverses,thehorizontalforcesapproachzeroasthepinstops,yieldinganartificiallylowcoefficientoffriction.ThegroupofdatapointsbetweentheminimacorrespondstodataobtainedalongthestraightlinepathbetweenPointAandPointBinFig.1.Itshouldbenotedthattheoutputfromthethreestationswasslightlyoffsetanddataweresynchronizedbyaligningthemaximumpointsofthethreeoutputs.Asaresultofthenoiseinthedata,itisnecessarytoanalyzeanumberofpointsineachcycleinordertoestimatethecoefficientoffriction.Todeterminetheappropriatenumberofdatapointsforthis,thestandarderrorofthemeanof5,10,15,20,25,30,35,40,45and50frictioncoefficientdatapointsaboutthemidpointofthecyclewascomputed.Thenumberofcyclesrequiredtocomputetheaveragecoefficientoffrictionwasalsodetermined.Theaveragecoefficientoffrictionwascomputedforsevencyclesandcycle-to-cyclevariationwasdeterminedforeachstationandforthreeconsecutivetests.Theaveragesofthefirst3,4,5,6and7cyclesweredeterminedandcompared.6.Resultsanddiscussion6.1.WithincyclevariationsinmeasurementsInFig.6,thestandarderrorofthemeanof5,10,15,20,25,30,35,40,45and50frictioncoefficientdatapointsaboutthemidpointforthefirstcycleisplottedforthethreestationsusedinthetest.Asexpected,thevariabilityofthecalculationofthecoefficientoffrictiondecreasedasthenumberofpointsisincreased.However,anasymptoticvalueofthestandarderrorofthemeanwasobservedat30–35points.Assuch,itwasdeterminedthatusing30datapointsaboutthemidpoint(61pointsintotal)wassufficientforcomputationofthecoefficientoffriction.6.2.BetweencyclevariationsinmeasurementsTodeterminecycle-to-cyclevariation,midpointaveragesforthefirst3,4,5,6and7cyclesweredetermined.Theseaverageswerealmostidentical,withamaximumdifferencebetweenthecycleaveragesoflessthan0.0003(approximately1%).Furthermore,thedifferenceinbetween-cycleaveragevalueswasoneorderofmagnitudelowerthandifferencesobservedbetweentestsorbetweenstations.Assuch,anestimatefortheuncertaintyinthecoefficientoffrictionmeasurementwasbasedthestandarddeviationfrom183datapoints(61datapointspercycleandthreecycles).Acrossallexperiments,thestandarddeviationvariedfrom0.0041to0.0099,whichresultedinastandarderrorofthemeanrangingfrom0.0005to0.0012.Withcoefficientsoffrictionintherangeof=0.03,thisrepresentsanuncertaintyof2–4%inthemeasuredvalueforaspecificstationandsample.6.3.Variationinmeasurementswithtest,station,anddirectionofmotionAnadditionalobservationfrommanytestswasthepresenceoftwogroupsofdatawithslightlydifferentaveragevaluesofthecoefficientoffriction.ThisisillustratedinFig.5inwhichthemidpointaveragesappeartoalternatebetweenhigherandlowervalues.Usingthe30-pointand3-cyclecriteria,thecoefficientsoffrictionwerecomputedafter10,000cyclesforthreestationsandthreetestsassummarizedinTables1and2fortheslightlyhigherandlowervaluegroupsrespectively.Thestandarddeviations()obtainedfromstation-to-stationandfromtest-to-testarealsoindicated.Forthehighercoefficientoffrictiongroup,theoverallmeanwas=0.0381.Thepooledstandarddeviationbetweenstationswas=0.0048andthatobtainedbetweentestswas=0.0046.CoefficientsoffrictionforthelowervaluegroupsareshowninTable2,withameanof=0.0352andstandarddeviationsbothbetweentestsandstationsof=0.0048.AnunpairedStudent’st-testwasconductedandthedifferencebetweentheaveragecoefficientoffrictionobtainedfromthelowerandthehighervaluegroupswasnotstatisticallysignificantatthe5%level.Thereforetheaveragevalueofbothgroups(=0.0367)canbereported.Thenearequivalenceofthestandarddeviationsindicatesthatstrategiesforexperimentaldesigncanbebasedonusingeithermultiplestationssimultaneouslyormultiplesamplesonasinglestationsequentially.Forexample,ifoneweretoassumeaconservativevalueforthestandarddeviationof=0.005andacoefficientoffrictionof=0.0367thena20%effectsize(0.0073)couldbedetectedwithasamplesizeof8at?=0.05withapowerof0