基于PROE平臺(tái)的立式雙軸缸孔半精鏜機(jī)床總體及刀具設(shè)計(jì)【說明書+CAD+PROE】,說明書+CAD+PROE,基于PROE平臺(tái)的立式雙軸缸孔半精鏜機(jī)床總體及刀具設(shè)計(jì)【說明書+CAD+PROE】,基于,proe,平臺(tái),立式,雙軸缸孔半精鏜,機(jī)床,總體,整體,刀具,設(shè)計(jì),說明書,仿單,cad 外文翻譯 專 業(yè) 機(jī)械設(shè)計(jì)制造及自動(dòng)化 學(xué) 生 姓 名 康 生 班 級(jí) BD機(jī)制042 學(xué) 號(hào) 0420110225 指 導(dǎo) 教 師 黃曉峰 外文資料名稱：Design and manufacture of composite high speed machinetool structures 外文資料出處：Composites Science and technology 附 件： 1.外文資料翻譯譯文 2.外文原文 指導(dǎo)教師評(píng)語(yǔ)： 簽名： 年 月 日 復(fù)合高速機(jī)刀具結(jié)構(gòu)的設(shè)計(jì)與制造 Dai Gi lLee,Jung Do Suh, Hak Sung Kim, Jong Min Kim 摘要 高傳輸速度，以及高切削速度機(jī)床重要的是生產(chǎn)力的提高，在制作模具/模具，因?yàn)榉羌庸r(shí)間，被稱為空中交織的時(shí)間，數(shù)量，以70 ％的總加工時(shí)間與形狀復(fù)雜的產(chǎn)品。其中一個(gè)最主要的原因是生產(chǎn)率低，是大型群眾性的運(yùn)動(dòng)部件的機(jī)床，其中不能負(fù)擔(dān)快的加速和減速過程中遇到的操作。此外，振動(dòng)機(jī)床結(jié)構(gòu)是其他原因限制，高速運(yùn)作。 在這個(gè)文件中，幻燈片的高速數(shù)控銑床的設(shè)計(jì)與纖維增強(qiáng)復(fù)合材料克服這種局限性?？v向和橫向的幻燈片大型數(shù)控機(jī)床制造加入高含量碳纖維環(huán)氧復(fù)合材料，以鋼筋焊接結(jié)構(gòu)用粘合劑和螺栓。這些復(fù)合材料結(jié)構(gòu)減少重量縱向和橫向的幻燈片，由34 ％和26 ％ ，分別增加了阻尼。不致有太大調(diào)整，這臺(tái)機(jī)器上進(jìn)行了定位精度5光鏡每300毫米的減少。 1.導(dǎo)言 數(shù)控銑床和加工中心應(yīng)用于制作各種模具/模具即用于家電，汽車內(nèi)飾， 沖壓和注塑成型。在正常加工與機(jī)床，其切削工具提出與名義利用率，而價(jià)格切換至快速導(dǎo)線模式轉(zhuǎn)移期間切削工具，如果沒有接觸工件：時(shí)間用于傳輸一個(gè)刀具無接觸工件的，是所謂的空切時(shí)間。一般來說，只有大約30 ％的總加工時(shí)間是花費(fèi)在實(shí)際切削，而其余的70 ％ 是花在空中交織的兼職[1,2]。因此，不只是具有高的切削速度，而且具有較高的傳輸速度，是必須取得資源增值的加工這是必不可少的條件，在全球競(jìng)爭(zhēng)機(jī)床市場(chǎng)，雖然切割速度已增加是由于新研制的切削刀具材料，如陶瓷，立方氮化硼，金剛石等，生產(chǎn)力仍受制于低轉(zhuǎn)移高速大規(guī)模移動(dòng)幀，其中通常是鋼。傳統(tǒng)的鋼標(biāo)架的機(jī)工具與最高速度為0.2?0.8米/秒， 最大加速度0.2-2.1m/s2（常規(guī)加工中心，mynx400/ace-tc320d，大宇重工機(jī)械有限公司，韓國(guó)）。然而， 現(xiàn)代高速銑床須有最大加速度14 m/s2和速度。 2米/秒。這些高傳輸速度，是難以實(shí)現(xiàn)如果龐大的鋼鐵架利用。 此外，機(jī)床結(jié)構(gòu)振動(dòng)形成問題，在制造過程中，在這些高的速度，而可能導(dǎo)致質(zhì)量低劣產(chǎn)品的相對(duì)位置誤差在刀具和工件[3-5]之間：最近機(jī)床都要求有一直被定位精度在10lm的，其中是密切相關(guān)的精密產(chǎn)品。為保證高速運(yùn)行的準(zhǔn)確性，機(jī)床結(jié)構(gòu)設(shè)計(jì)應(yīng)與輕動(dòng)框在不消耗剛度和阻尼性能， 這是相互矛盾的要求，如果常規(guī)金屬材料是受雇于常規(guī)金屬幾乎相同的低比剛度（五= q ）的同低阻尼特性。機(jī)床結(jié)構(gòu)高剛度和高阻尼要求，以增加他們的基本自然頻率并減少振動(dòng)引起的。要求要比高剛度高阻尼的機(jī)床結(jié)構(gòu)能滿足用人纖維增強(qiáng)聚合物復(fù)合材料。增強(qiáng)纖維復(fù)合材料構(gòu)成的加固纖維具有很高的具體剛度和矩陣高阻尼，由此產(chǎn)生的材料復(fù)合特性反映最佳的特點(diǎn)，即高比剛度、高阻尼。此外，夾層結(jié)構(gòu)，其面結(jié)構(gòu)制成的纖維增強(qiáng)復(fù)合材料、其核心材料制成的蜂窩狀或發(fā)泡結(jié)構(gòu)，最大限度地發(fā)揮優(yōu)勢(shì)的時(shí)候，他們適用于結(jié)構(gòu)抵抗彎矩。 因此，夾層結(jié)構(gòu)和復(fù)合材料我們已使用的越來越多，在宇宙飛船飛機(jī)，汽車零部件，機(jī)器人手臂 ，甚至機(jī)床 。 變形的機(jī)床結(jié)構(gòu)下切削力和結(jié)構(gòu)慣性負(fù)載啟動(dòng)過程并停止生產(chǎn)，不僅產(chǎn)品質(zhì)量差，而且有很強(qiáng)噪音和振動(dòng)。然而，這增加了一般的機(jī)床結(jié)構(gòu)，因此需要大量電動(dòng)機(jī)，軸承和運(yùn)動(dòng)指導(dǎo)體系。因此， 最好的方法，以提高剛度的機(jī)床結(jié)構(gòu)，沒有多大增加部件是使用高比剛度的結(jié)構(gòu)，如復(fù)合材料夾層結(jié)構(gòu)。 在這項(xiàng)研究中，縱向和橫向機(jī)床幻燈片的高速數(shù)控銑床的設(shè)計(jì)及制造所用復(fù)合材料夾層結(jié)構(gòu)是膠接，以焊接鋼管結(jié)構(gòu)-一種混合機(jī)床結(jié)構(gòu)。垂直柱的橫向滑動(dòng)（十-幻燈片）及制造與復(fù)合材料夾層結(jié)構(gòu)，而橫欄的垂直滑動(dòng)（ Y型幻燈片） 鋼筋與高模量復(fù)合板。該混合結(jié)構(gòu)設(shè)計(jì)成具有等效結(jié)構(gòu)剛度的常規(guī)鋼結(jié)構(gòu)這是按經(jīng)典梁理論分析。此時(shí)，自然頻率和阻尼能力以及減輕重量的復(fù)合材料混聯(lián)機(jī)床結(jié)構(gòu)測(cè)定和相對(duì)于常規(guī)鋼機(jī)床結(jié)構(gòu)。 2.設(shè)計(jì)混聯(lián)機(jī)床結(jié)構(gòu) 2.1特色的混合型梁 抗彎剛度簡(jiǎn)支夾心束所示圖。 (1) 如s模面和核心。偏轉(zhuǎn)長(zhǎng)簡(jiǎn)支持夾層梁下的集中載荷P基于簡(jiǎn)單梁理論是指用D1的原因彎曲變形和D2由于剪切變形[15,16] 凡與GC代表等效截面面積和剪切模芯材料，分別由于夾層結(jié)構(gòu)具有較低的核心剪切剛度， 簡(jiǎn)單梁理論，忽略剪切變形可能不會(huì)作出準(zhǔn)確的結(jié)果。因此，在計(jì)算結(jié)果剛度的夾層梁標(biāo)本相比與實(shí)測(cè)結(jié)果所得到的三點(diǎn)彎曲試驗(yàn)表明，在圖 1以及作為結(jié)果由有限元分析。三點(diǎn)彎曲試驗(yàn)是用英斯特朗4206年不足1毫米/分鐘位移速率和有限元分析是演出與商業(yè)軟件ANSYS5.5（美國(guó)）使用殼牌99和固體95元素。表1顯示尺寸夾心標(biāo)本。夾心束標(biāo)本制成的復(fù)合材料的表面和內(nèi)部核心。加入表面和核心，即是一種粘合劑形狀（ af126 ， 3 M公司，美國(guó)）和環(huán)氧粘合劑圖1。尺寸的簡(jiǎn)支夾層梁用三點(diǎn)彎曲試驗(yàn)： （一）縱向方向; （二） 橫截面A-A1。 。 表1 尺寸（ mm ）的簡(jiǎn)支夾層梁下threepoint 彎曲試驗(yàn) （2216，3M公司，美國(guó)） ，是用來防止脫層失敗的夾層結(jié)構(gòu)[17,18]。單向碳纖維環(huán)氧復(fù)合（ usn150 ，韓國(guó)化學(xué)，韓國(guó)） 與玻璃纖維布復(fù)合（ gep215 ，韓國(guó)化學(xué)， 韓國(guó)）被用于表面材料，而芳綸纖維蜂窩（ hrh-10-1/8-4.0 ， hexcel ，英國(guó)） 用于核心材料。表2和表3列出性能這些材料。綜合面孔為夾心基礎(chǔ)打下了一個(gè)堆疊序列[ 0 2 100 / 0 10歲;的C / 0 1 100 / 0 5年;中] s凡標(biāo)G和C代表了玻璃纖維和碳-環(huán)氧分別。 圖2顯示實(shí)測(cè)撓度以及由于計(jì)算的，由梁理論和有限元分析。梁理論和有限元分析預(yù)言實(shí)驗(yàn)偏轉(zhuǎn)8 ％以內(nèi)的誤差。 從以上結(jié)果，我們發(fā)現(xiàn)在這該夾層梁撓度因剪是不容忽視（在這種情況下3倍以上，由于彎曲）。 因此，箱式混合梁方面鋼筋與鋼板所示圖。 3 采用混合標(biāo)架，以減少剪切變形的夾層梁。對(duì)于梁的鋼筋與鋼板忽視翹曲，剪應(yīng)力和，它的幾何兼容性詳情如下： 其中R的比例應(yīng)是剪切模量之間的鋼和蜂窩項(xiàng)。然后，剪應(yīng)力蜂窩圖。 2.2設(shè)計(jì)的重量輕的復(fù)合鋼筋機(jī)工具框 圖4顯示照片的高速數(shù)控機(jī)床銑床的15千瓦配備35000rpm時(shí)， 圖4 照片上的高速銑床結(jié)構(gòu)（ f500 ，大宇重工機(jī)械有限公司，韓國(guó)）。 主軸及混合標(biāo)架，水平坐標(biāo)（十-坐標(biāo)）及垂直坐標(biāo)（ Y型坐標(biāo)） ，其垂直柱和橫向柱鋼筋與復(fù)合材料夾層結(jié)構(gòu)和復(fù)合材料板（ f500 ，大宇重工＆ 機(jī)械有限公司，韓國(guó)） 。無論是移動(dòng)所得到了2.0米/秒的速度，還是達(dá)到最大加速度14.0 m/s2 ，都無結(jié)果。 5和6顯示照片的X坐標(biāo)和Y型坐標(biāo)組成的復(fù)合材料夾層結(jié)構(gòu)膠接，以焊接鋼管結(jié)構(gòu)。為了估計(jì)該機(jī)床結(jié)構(gòu)撓度，在高加速度， 移動(dòng)鋼框架結(jié)構(gòu)進(jìn)行了分析，得到了有限元分析顯示圖。 如垂直的X坐標(biāo)抵消了所吸收的20千牛力量產(chǎn)生的，由兩個(gè)直線電機(jī)裝內(nèi)表面的垂直方向的X -坐標(biāo)。 橫欄的Y型滑坡發(fā)生變形，在Z向由彎矩由于要伸出主軸重量4000 N，以最大限度地加固效果，在這項(xiàng)工作中，立柱的X -坐標(biāo)和橫向欄的Y坐標(biāo)被選作主要加強(qiáng)部分。 為了發(fā)展一個(gè)打火機(jī)，混合幀的X幻燈片鋼鐵基地，制成更薄的鋼板的16毫米厚度相比， 20毫米厚的鋼板。 常規(guī)之一，是增強(qiáng)復(fù)合材料夾層結(jié)構(gòu)顯示圖。自剪變形的一個(gè)簡(jiǎn)單的三角形結(jié)構(gòu)通常大，在這項(xiàng)研究中，混合結(jié)構(gòu)的目的是作為盒型結(jié)構(gòu)參考。 后來，其雙方均加強(qiáng)了鋼鐵板塊。 為設(shè)計(jì)的箱式混合結(jié)構(gòu)大于10.4 ，這意味著偏轉(zhuǎn)由于剪切小于8.8 ％的總偏轉(zhuǎn)。因此，在設(shè)計(jì)中的結(jié)構(gòu)，抗彎剛度D的使用為目標(biāo)參數(shù)，如 由于加固外，以增加抗彎剛度d時(shí)，內(nèi)面厚度的夾心決定考慮加入5毫米的內(nèi)在面臨的夾層梁，以鋼鐵為主，以螺栓為主。 厚度外，面對(duì)的夾層梁被初步確定給予最主要的一個(gè)，然后再較具體的計(jì)算其中，以確定合適的尺寸并利用有限元法考慮當(dāng)?shù)芈N曲或扭曲。從分析中，它是發(fā)現(xiàn)較大偏轉(zhuǎn)發(fā)生在混合動(dòng)力梁時(shí)，都梁有相同的抗彎剛度d ，因?yàn)榻粖A不具備橫向加固鋼板，而常規(guī)鋼梁被設(shè)計(jì)成一個(gè)格子型結(jié)構(gòu)與加強(qiáng)板，圖 9 。因此，外面厚度的夾層梁增加至13毫米。 此外，尺寸的其他援軍計(jì)算通過程序入手等效抗彎剛度D和計(jì)算，然后與有限元法考慮翹曲的結(jié)構(gòu)。 2.3 制造混聯(lián)機(jī)床結(jié)構(gòu)高強(qiáng)度碳纖維環(huán)氧復(fù)合（ usn150 ，韓國(guó)化學(xué)，韓國(guó)）和玻璃纖維環(huán)氧（ gep215 ，韓國(guó)化學(xué)，韓國(guó)） ，主要用于面孔夾層梁和加固板為X和Y型幻燈片。垂直欄的X抗滑被鋼筋與兩個(gè)夾層梁的1462毫米和1223毫米長(zhǎng)，而在頂部和底部部分鋼筋分別與四個(gè)復(fù)合板六小夾層梁所示圖 5 。該Y型幻燈片，即主軸單元的銑削應(yīng)該抵制彎矩產(chǎn)生主軸的重量，切削力和慣性力由于快速加速和減速而下落了。 橫欄的Y型幻燈片與嚴(yán)格的三維制約因素是鋼筋，具有很高的彈性模量碳纖維環(huán)氧復(fù)合材料的性能，給出表2 （ hyej34m45d ，三菱，日本） ，以避免干擾其他部分。此外，左右垂直柱的Y型幻燈片被鋼筋與三角梁所示圖6。此外，四個(gè)三角形板被用于加強(qiáng)扭剛度的矩形框。綜合增援保稅區(qū)向鋼鐵基地結(jié)構(gòu)與環(huán)氧粘合劑（2216 ，3M公司，美國(guó)）精神結(jié)合起來，同機(jī)械結(jié)合，與螺栓，以提高可靠性和生產(chǎn)效率。 Design and manufacture of composite high speed machinetool structures Dai Gil Lee *, Jung Do Suh, Hak Sung Kim, Jong Min Kim Abstract The high transfer speed as well as the high cutting speed of machine tools is important for the productivity improvement in thefabrication of molds/dies because non-machining time, called the air-cutting-time, amounts to 70% of total machining time withcomplex shape products. One of the primary reasons for low productivity is large mass of the moving parts of machine tools, whichcannot afford high acceleration and deceleration encountered during operation. Moreover, the vibrations of the machine toolstructure are among the other causes that restrict high speed operations.In this paper, the slides of high speed CNC milling machines were designed with fiber reinforced composite materials toovercome this limitation. The vertical and horizontal slides of a large CNC machine were manufactured by joining high-moduluscarbon-fiber epoxy composite sandwiches to welded steel structures using adhesives and bolts. These composite structures reducedthe weight of the vertical and horizontal slides by 34% and 26%, respectively, and increased damping by 1.5–5.7 times withoutsacrificing the stiffness. Without much tuning, this machine had a positional accuracy of
5 lm per 300 mm of the slidedisplacement. 1. Introduction CNC milling machines and machining centers areemployed in the fabrication of various molds/dies thatare used for electrical appliances, automobile interiors, stamping and injection molding. During normal machiningwith machine tools, their cutting tools aremoved with nominal feed rates, while the feed rates are switched to a rapid traverse mode during the transfer ofcutting tools without contacting workpieces: The timespent to transfer a cutting tool without contactingworkpieces is called air-cutting-time. Generally, onlyabout 30% of the total machining time is spent in theactual cutting or making chips, while the remaining 70%is spent in the air-cutting-time [1,2]. Therefore, not onlyhigh cutting speeds but also high transfer speeds arerequired to obtain the enhanced productivity of machiningwhich is essential to survive in the global competitionof machine tool markets. Although the cuttingspeed has been increased due to newly developed cuttingtool materials such as ceramic, CBN, diamond and soon, productivity is still restricted by the low transferspeed of massive moving frames which are usually madeof steel. Conventional steel moving frames of machinetools operate with maximum speeds of 0.2–0.8 m/s, andmaximum acceleration of 0.2–2.1 m/s2 (ConventionalMachining Center, Mynx400/ACE-TC320D, DaewooHeavy Industries & Machinery Ltd., Korea). However,modern high speed milling machines are required tohave the maximum acceleration of 14 m/s2 and the speedof 2 m/s. These high transfer speeds are hard to be realizedif massive steel moving frames are employed.Furthermore, machine tool structures vibrate creatingproblems during manufacturing at these high speeds,which may result in poor quality products by the relativepositional error between the cutting tools and workpieces[3–5]: Recently machine tools are required to havebeen kept the positional accuracy within
10 lm, whichis closely related to the precision of products [6]. For thehigh speed operation with accuracy, machine toolstructures should be designed with light moving frameswithout sacrificing stiffness and damping properties,which are contradictory requirements if conventionalmetallic materials are employed because conventionalmetals have almost same low specific stiffness (E=q) withlow damping characteristics. Machine tool structureswith high specific stiffness and high damping are requiredto increase their fundamental natural frequenciesand decrease the vibration induced. The requirement ofhigh specific stiffness with high damping for high speedmachine tool structures can be satisfied by employingfiber reinforced polymer composite materials [7,8]. Sincethe fiber reinforced composite materials consist of reinforcingfibers with very high specific stiffness and matrixwith high damping, the resulting material characteristicsof composite materials reflect the best characteristics ofeach material, i.e., high specific stiffness with highdamping. Moreover, sandwich structures whose facestructures are made of fiberreinforced composite materialsand whose core materials are made of honeycombor foam structures maximize their advantages when theyare applied to the structures resisting bending moment.Consequently, sandwich structures and composite materialshave been employed increasingly in spacecrafts,airplanes, automobile parts [9], robot arms [8,10], andeven machine tools [11,12].The deformation of machine tool structures undercutting forces and structural inertia loads during startand stop motions produces not only poor qualityproducts but also noise and vibration. A simple way toreduce the deformation is to employ structures withlarge cross-sections. However, it increases the mass ofmachine tool structures and consequently requires largemotors, bearings and motion guide systems. Therefore,the best way to enhance the stiffness of machine toolstructures without much increase of mass is to employhigh specific stiffness structures such as compositesandwich structures.In this study, the vertical and horizontal machine toolslides of a high speed CNC milling machine were designedand manufactured with sandwich compositestructures that are adhesively bonded to welded steelstructures – a hybrid machine tool structure. The verticalcolumn of the horizontal slide (X-slide) was manufacturedwith composite sandwich structures while thehorizontal column of the vertical slide (Y-slide) wasreinforced with high modulus composite plates. Thehybrid structures were designed to have the equivalentstructural stiffness of conventional steel structures,which was calculated by the classical beam theory andFEM analysis. Then, the natural frequency and dampingcapacity as well as weight savings of the compositehybrid machine tool structures were measured and compared with those of comparable conventional steelmachine tool structures. 2. Design of hybrid machine tool structures 2.1. Characteristics of hybrid beam The bending stiffness D of a simply supported sandwichbeam as shown in Fig. 1 is expressed as followswhen Ef >> Ec and d >> t [13–15]: ( 1) where Ef and Ec represent the Young
s moduli of faceand core, respectively. The deflection D of the simplysupported sandwich beam under a concentrated load P based on the simple beam theory is the sum of D1 due tobending deformation and D2 due to shear deformation[15,16]: where A and Gc represent equivalent cross-section areaand the shear modulus of core material, respectively.Since the sandwich structure has low core shear stiffness,the simple beam theory neglecting shear deformationmay not give an accurate result. Therefore, the calculatedresults of stiffness of sandwich beam specimen werecompared with the measured results obtained by thethree-point bending test shown in Fig. 1 as well as theresults by FEM analysis. The three-point bending testwas performed using Instron 4206 under 1 mm/mindisplacement rate and the FEM analysis was performedwith a commercial software ANSYS 5.5 (USA) usingshell 99 and solid 95 elements. Table 1 shows the dimensionsof sandwich specimens. The sandwich beamspecimens were made of composite faces and honeycombcore. To join the faces and the core, both an adhesivefilm (AF126, 3M, USA) and an epoxy adhesive Fig. 1. Dimensions of the simply supported sandwich beam used forthree-point bending test: (a) longitudinal direction; (b) cross-section ofA–A1. Table 1 Dimensions (mm) of the simply supported sandwich beam under threepointbending test (2216, 3M, USA) was used to prevent delaminationfailure of sandwich structures [17,18]. Unidirectionalcarbon-epoxy composite (USN150, SK Chemical, Korea)and glass fabric composite (GEP215, SK Chemical,Korea) were used for the face material while aramid fiberhoneycomb (HRH-10-1/8-4.0, Hexcel, UK) wasused for the core material. Tables 2 and 3 list theproperties of these materials. The composite faces forthe sandwich specimens were laid up with a stackingsequence of [02;G/010;C/01;G/05;C]S where the subscriptsG and C represent glass-fabric and carbon-epoxy, respectively.Fig. 2 shows the measured deflection as wellas the calculated ones by the beam theory and FEManalysis. Both the beam theory and the FEM analysispredicted the experimental deflection within 8% error.From the above results, it was found that the deflectionof the sandwich beam due to shear was not negligible(three times larger than that due to bending in this case).Therefore, box type hybrid beams with side surfacesreinforced with steel plates as shown in Fig. 3 wereadopted for the hybrid moving frames to reduce theshear deformation of the sandwich beam. For the boxtype beams reinforced with steel plates neglectingwarping, the shear stress sxz;h in the honeycomb and sxz;sin the side steel are related from the geometric compatibilityas follows: where R is the ratio of the shear moduli between the steel(Gxz;s) and honeycomb (Gxz;h). Then, the shear stress inthe honeycomb in Fig. 2.2. Design of light weight composite reinforced machinetool frames Fig. 4 shows the photograph of a high speed CNCmilling machine of 15 kW equipped with 35,000 rpm Fig. 4. Photograph of a high speed milling machine tool structure(F500, Daewoo heavy industries & Machinery Ltd., Korea). In order to develop a lighter hybrid frame, the X-slidesteel base, made of thinner steel plates of 16 mmthickness compared to 20 mm thick steel plates for conventional one, was reinforced with composite sandwichstructure as shown in Figs. 5 and 8. Since the sheardeformation of a simple sandwich structure is usuallylarge, in this study, the hybrid structure was designed asa box type structure as shown in Figs. 8 and 9 whosesides were reinforced with steel plates. The calculatedvalues of RBS from Eq. (7) for the designed box typehybrid structure was larger than 10.4, which meant thatthe deflection due to shear was less than 8.8% of thetotal deflection. Therefore, during the design of thestructure, the flexural rigidity D was used as the objectiveparameter, where Since the reinforcement of the outer face of the movingframes is most effective to increase the flexural rigidityD, the inner face thickness of the sandwich was determinedto be 5 mm considering the joining of the innerfaces of the sandwich beams to the steel base with bolts. 14