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畢業(yè)設計(論文)任務書
學生姓名: 學號:
學 院: 專業(yè):
任務起止時間:2011 年 3 月 8 日至 2011 年 7 月 2 日
畢業(yè)設計(論文)題目:
車銑加工中心左右立柱結構與工藝面制造工藝設計
畢業(yè)設計工作內(nèi)容:
1. 技術查新、資料檢索和翻譯;(2周)
2. 左右立柱結構的分析;(4周)
3. 左右立柱的結構設計;(5周)
4. 左右立柱與工藝面制造工藝設計;(4周)
5. 論文整理、答辯。(2周)
資料:
1. 周濟,周艷紅,數(shù)控加工技術,國防工業(yè)出版社,2003(04).
2. 《機床設計手冊》編寫組,機床設計手冊,機械工業(yè)出版社.1986(12).
3. 張伯霖. 高速切削加工技術在美國的最新發(fā)展.制造技術與機床, 1994.4
4. 劉雄偉,數(shù)控加工技術與編程技術,機械工業(yè)出版社.2000(03).
5. 梁玉平. 高速切削刀具材料. 機械工程材料, 1994.5
6. 艾興. 超高速切削加工技術. 機械工業(yè)出版社, 2003.1
7. 龔景安,許立忠.機械設計(第二版),機械工業(yè)出版社.1998(02)
指導教師意見:
簽名:
2010年2 月28日
系主任意見:
簽名:
2010年3月5日
教務處制表
畢業(yè)設計(論文)開題報告
課題題目及來源:
題目: 車銑加工中心左右立柱結構與工藝面制造工藝設計
來源: 企業(yè)合作項目
課題研究的意義和國內(nèi)外研究現(xiàn)狀:
課題研究的意義:
立柱是數(shù)控機床中主要的構件之一,它支撐主軸系統(tǒng)。立柱的剛性是影響加工村度的要因素之一。目前,許多立式數(shù)控機床采用了龍門式立柱。所以龍門式立柱的結構和加工工藝對龍門機床產(chǎn)生重大影響
國內(nèi)外研究現(xiàn)狀:
我國機床立柱在進入21世紀后連續(xù)8年保持快速發(fā)展的良好形勢,我們的一些企業(yè)也能做出來,與機床要求相符合的立柱,但是他們是用普通機床做出高精度的功能部件,這些產(chǎn)品也能用在一些高檔的數(shù)控機床上面,但是它的精度的穩(wěn)定性和保持性不行,再加上原材料的問題和工藝水平問題
目前國外的機床立柱研究和國內(nèi)最大差別是精度與可靠性,以及機床立柱的制造工藝水平與質(zhì)量,這就是國外產(chǎn)品的最大優(yōu)勢。同時國外研究趨于低碳環(huán)保的制造模式,降低生產(chǎn)成本
(龍門架立柱標準節(jié)由四角的四根角鋼和與其內(nèi)側垂直連接的方框組成,每節(jié)立柱下端所連方框底面縮進立柱長度為L,其上端所連方框頂面伸出立柱長度為l,l<L。相鄰兩節(jié)立柱四角角鋼上下對應插接扣合,相鄰兩節(jié)立柱相鄰方框通過連接件連接。方框由四根角鋼連接而成,組成每節(jié)立柱下端所連方框的角鋼夾角斜向上方,組成每節(jié)立柱上端所連方框的角鋼夾角斜向下方)
課題研究的主要內(nèi)容和方法,研究過程中的主要問題和解決辦法:
課題研究的主要內(nèi)容:
1、根據(jù)其使用要求進行受力分析
2、根據(jù)其受力和其他因素(如安裝別的零部件),并參考現(xiàn)有立柱類型,初步?jīng)Q定其形狀和尺寸
3、與機床其它部件連接處結構設計
4、左右立柱與工藝面制造工藝設計
5、借助計算機進行驗算求其靜態(tài)和動態(tài)特性。
研究過程中的主要問題和解決辦法:
主要問題:通過受力和各連接件確定立柱各部分結構
解決方法:通過考察和調(diào)研,查閱相關資料,綜合應用專業(yè)的理論知識,掌握機械裝置的設計方法和步驟,在通過多次的計算校對,最后確定設計方案及設計參數(shù),進行設計安裝。
課題研究所需的參考文獻:
[1] 戴曙.金屬切削機床.機械工業(yè)出版社,1999:217-238
[2] 杜君文.機械制造技術裝備及設計.天津大學出版社,2007:26-33
[3] 周濟,周艷紅.數(shù)控加工技術. 國防工業(yè)出版社,2003(04)
[4] 《機床設計手冊》編寫組,機械設計手冊. 機械工業(yè)出版社,1986(12)
[5] 艾興. 超高速加工技術. 機械工業(yè)出版社.2003.1
[6] 梁玉平. 高速切削刀具材料. 機械工程材料.1994.5
[7] 劉雄偉. 數(shù)控加工技術與編程技術. 機械工業(yè)出版社.2000(03)
[8] 張伯霖. 高速切削技術在美國的最新發(fā)展. 制造技術與機床.1994.4
[9] 龔景安,許立忠. 機械設計(第二版).機械工業(yè)出版社.1988(02)
指導教師審查意見:
指導教師簽字:
20 年 月 日
指導委員會意見審核意見:
組長簽字:
20 年 月 日
附錄:外文原文和譯文
SIMULTANEOUS STRUCTURE AND MECHANISM DESIGN FOR AN ADAPTIVE WING USING TOPOLOGY OPTIMIZATION
James J. Joo Aerospace Mechanics Division University of Dayton Research Institute Dayton, OH 45469, USA
Brian Sanders Air Vehicles Directorate AirForce Research Laboratory Wright-Patterson AFB, Ohio 45433, USA
ABSTRACT
A synthesis technique using a topology optimization scheme for an adaptive wing structure and mechanism design will be described.This enables the design of energy efficient adaptive structures with controllable deformation characteristice.This is accomplished by using a multi-objective function that minimizes strain energy and maximizes mutual potential energy to design the structure and mechanism simultaneously.To enable simultaneous design for structure and mechanism, the reference structure is composed of three layers; a membrane layer for skin, a frame element layer for structure, and truss element layer for an efficient mechanism. The attachment points between mechanism and structure are also identified with linear springs that are located between mechanism and structure layers. We focus on a simultaneous design of a wing structure and mechanism for large shape change applications. The geometrically large deformation analysis scheme is also added to the synthesis to capture nonlinear effects in design and it will be compared with linear synthesis results.
INTRODUCTION
Adaptive structures are a multidisciplinary technology that requires the efficient integration of power systems, structures, mechanisms, and actuators to achieve the desired performance. Adaptive systems will have a dramatic impact on the design of air vehicle systems if new devices can be synergistically
integrated into systems. The basic research community has suggested a plethora of innovative concepts ranging from structural health monitoring to adaptive shape control using energy intensive smart materials. Smart material technologies have increased its potential application to provide a new opportunity for active/adaptive structure systems that fully integrate actuators and structures. The Defense Advanced Research Projects Agency (DARPA) recognizes the potential of this technology and initiated the Smart Materials and Structures Demonstration Program to demonstrate the use of smart materials to achieve aerodynamic and hydrodynamic flow control and to reduce noise and vibration in a variety of structures (Sanders, et. al, 2004).
New materials synthesized at the atomic level to produce new functionality are ideal for this application but the technology is very immature. Until now, smart materials or other adaptive technologies have been added to an existing structure to achieve a desired shape change a structure already designed to avoid deformation. For example, aircraft wings are designed to be stiff as possible to control aeroelastic effects, and then smart materials are attached on to it to get a higher lift coefficient by change airfoil shape. This system becomes very energy inefficient because you are trying to deform a structure that was alreadydesigned to prevent deformation. For this reason, researchers have designed in flexibility for their structure design. Lu and Kota (2003) have designed a compliant leading edge that matches a desired shape with a single actuation force. Others are investigating new design techniques for these applications. Maute et. al. (2005) used the topology optimization technique to design mechanisms in morphing aircraft structures including actuator characteristics. Also Mauteand Reich (2004) showed the simultaneous optimization of the mechanism layout of adaptive wing and aerodynamic tasks outperformed the decomposed two step procedure.
Designed properly, these structural concepts have the potential to revolutionize aircraft design and basic functionality. For example, the use of adaptive systems within unmanned air vehicles (UAV) will enable a multi-mission (e.g., hunter-killer) UAV by allowing the vehicle configuration to efficiently adapt to a wide range of mission roles, such as loiter and high speed dash. Here the best wings for each purpose have radically different planforms. Current research on morphing aircraft that exhibit very large shape changes requires more efficient ways of synthesizing out three major components; rigid-body mechanisms, structures and skins. In this paper, we propose to design an energy efficient adaptive structure for shape control purposes by designing structures and mechanisms simultaneously. A three-layer model is developed that is composed of a ground truss layer for mechanism design and a membrane and beam layers for structure design. A multi-objective function to maximize mutual potential energy to increase flexibility in desired direction and minimizing strain energy to withstand drag is adopted here.
NOMENCLATURE
Uo Dummy force in the desired output direction
Ui Dummy force in the input direction.
Fin Input force
Fex External force
[K] Global stiffness matrix
11spq2e Displacement vector
{f} Force vector
Km Element stiffness matrix of membrane element
Kt Element stiffness matrix of truss element
Kf Element stiffness matrix of frame element
Ks Element stiffness matrix of spring element
Maximum volume of truss element
Maximum volume of frame element
N* Maximum number of spring
P Penalty
ρf, s, t Density of frame, spring, and truss elements
REFERENCE STRUCTURE
The reference element composed of three layers is shown in Figure 1 below; the membrane element layer is for stretchable flexible skin. The truss element layer is for an energy efficient mechanism that generates motion using rigid body rotation rather than the deformation of elements to change the shape. Using frame elements, most of energy will be stored in the mechanism rather than transformed to the output port which results in an inefficient mechanism. Also this truss element with rigid body rotation is more appropriate for large shape changing applications than frame elements due to the similar reason. This truss element layer is connected to the membrane elements layer by springs and this is for identifying connection points between structure and mechanism. Spring stiffness is chosen based on the following criteria (Chandrupatla 1997) to bond mechanism and membrane layer together:
C=max∣kij∣×103 (1
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