輕型貨車后驅(qū)動(dòng)橋設(shè)計(jì)

喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢QQ:1064457796或者1304139763 ==================== 喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢QQ:1064457796或者1304139763 ==================== 任務(wù)書(shū) 專業(yè) 班級(jí) 學(xué)生 設(shè)計(jì)題目 輕型貨車后驅(qū)動(dòng)橋設(shè)計(jì) 課題來(lái)源 起訖日期 年 月 日至 年 月 日 指導(dǎo)教師（簽名） 教研室主任（簽名） 課題依據(jù) 一、相關(guān)整車參數(shù) 　　　1.汽車滿載質(zhì)量3720KG 前軸1380KG 后軸2340KG 　　　2.整載質(zhì)量2700KG 　　　3.主減速比6.28 　　　4.變速器比5.568 2.832 1.634 1.00 0.75 倒擋4.79 　　　5.發(fā)動(dòng)機(jī)最大功率75KM/2900rpm 　　　6.最大轉(zhuǎn)距190.8N.M/1700-1800rpm 二、參考文獻(xiàn) 1.《汽車設(shè)計(jì)》，劉惟信，清華大學(xué)出版社； 2.《機(jī)械設(shè)計(jì)手冊(cè)》，第三版，第1、2卷； 3. GB/T7258—2004《機(jī)動(dòng)車運(yùn)行安全技術(shù)條件》。 任務(wù)要求： 1.繪制后驅(qū)動(dòng)橋包括前、后，右等方向視圖和必要的剖視圖，要有零件圖。圖紙要符合相關(guān)標(biāo)準(zhǔn)。工作量不少于2張半零號(hào)圖紙。 2.編寫(xiě)設(shè)計(jì)計(jì)算說(shuō)明書(shū)，字?jǐn)?shù)不少于8000，并有中英文摘要。 3.翻譯不少于3000外文字符的相關(guān)外文資料。 4.提交不少于3000字的調(diào)研報(bào)告或資料綜述。 設(shè)計(jì)進(jìn)度計(jì)劃 起訖日期 工 作 內(nèi) 容 備 注 3.24～3.31 4.1～4.15 4.16～5.10 5.11～6.31 6.1～6.5 6.6～6.14 熟悉課題，收集資料 翻譯外文資料，撰寫(xiě)資料綜述或調(diào)研報(bào)告 確定方案，設(shè)計(jì)計(jì)算，繪制草圖 繪制總裝圖及零件圖 撰寫(xiě)說(shuō)明書(shū) 完成論文PPT，準(zhǔn)備答辯 備注 4 外文文獻(xiàn)原文： Drive axle is one of the important bearing automobile assembly, the property can directly affect the vehicle performance and service life. Driving bridge like a bridge shell, the main reducer, differential and half shell and other components, turn to drive the bridge also includes a variety of constant velocity coupling,The structure is more complex.The traditional design is based on the production experience as the foundation, using mechanical, number and the regression formula, formation of charts, manuals for the modern design is the traditional design of deep, rich and the development, rather than the new design independent from the traditional design. The computer technology as the core the heart, in order to design theory as the guide, is a main character of modern design. Using this method to guide the design can reduce the blindness of design and experience arbitrariness, improve the initiative, scientific and accurate design.Similarly, research on the driving axle should not only stay in the traditional design .Method, but with the aid of the modern design method to refine on. This the research on driving modern design method of bridge to do more deep.In the study, the various design methods with each other, according to different design content separately using different method, in order to promote its design.History tends to be more reasonable and scientific 1CAD/CAE Technology CAD is the use of computer system in the engineering and product design.Each stage provides a variety of fast, effective tools and designers.Means, to accelerate the optimization and design process and design results,in order to achieve the best design technology. The application of CAD technology in mechanical products design meter, which can not only shorten the design cycle, but also can improve the precision of the design and reliability, so as to realize the optimization and automation of the design process.The development of an open, integrated and intelligent trend.At present, the 3D CAD modeling software commonly used with Pro/E, UG,MDT, Solid Works, Auto CAD etc.. Pro/E is a kind of CAD/CAE/CAM software system integration, with a strong practical body shape and surface modeling function, can be constructed very complex models. The resulting model can form assembly, and can generate the model zero Mold. Whether the part model, assembly model or die type, can be transformed into the two-dimensional engineering drawings. It uses a single database,The corresponding data can automatically modify the stage at any stage.Finite element technology in CAE is a mathematical calculation, calculation of the force Science and Engineering Science, born in the most effective calculation method. Form the enriched finite element method, a theoretical basis for improving, and have a general finite element program, the use of these software can solve large scale science and engineering computation problem of numerous,finite element calculation The fruit has become the design and performance analysis of all kinds of industrial products reliable basis. According to. Many finite element analysis program of the finite element analysis, computer graphics study and optimization technology together, form a computer aided complete analysis of the system, can significantly improve the performance of product design, shorten the design cycle Period, enhance the competitiveness of products.In many finite element analysis software, ANSYS is the most general One of the effective software, it has enriched and improved cell library,material model base and solver, ensure efficient solving the structural static force, force, vibration, linear and nonlinear problems and thermal analysis and structure coupling problem, the advanced analysis techniques can be parameterized The design, optimization and topology optimization. CAD/CAE technology is big in the research and design of driving axle play. For new products, using CAD to create the drive axle of each element The entity model, the model is calculated by CAE, test Its performance meets the requirements. If you don't meet the requirements can modify the model type, until satisfied. Finally the model into the engineering diagram, can manufacturing products. If the CAD/CAE and CAM or rapid prototyping technology combined, can significantly shorten the production from design to manufacturing product cycle, parts library can also generate existing parts, in order to facilitate the similar or the design of series of drive axle. Of course, the strength and the existing parts Failure analysis and improvement are also often used this method In the analysis of a mini car special damage reason of drive axle housing, Reference [1] by using the CAD/CAE method. We use the 3-D CAD modeling software De as to build the bridge shell model, then there is The finite element method to calculate, found that local stress concentration occurs, the regional and regional anastomosis failure. Using different ways to fix the model Instead, the modified model and calculate the stress distribution, find a good change good plan. Improved drive axle used in good condition. Reference [2] CAD/CAE technology and C language combination, using C language in the "class" of the system control module and the function module elements and package member function, the optimal range of drive axle product data model, to maximize the use of existing design resources. 2Reliability Engineering Reliability engineering is based on probability and stochastic distribution,research structure in the requirements and within the time specified, complete function probability. Research on stochastic phenomenon long-standing, but in its work The application process is not accompanied by. The traditional design that the material Body performance (strength, toughness and hardness) and the stress is a constant, in order to guide product conservative. Considering the randomness and reliability is introduced in the design, to reflect the objective reality, Thus the design of products is also more scientific, reasonable. Now, some developed Some parts of the country of design and manufacture, the life can be accurate to hours, If there is no reliability calculation, is unthinkable.The calculation method of reliability of mechanical structure commonly used is a two order moments method. The state function (strength and stress difference on the mean point)Expansion in Taylor series, ignoring the more than two times, we can get the reliability Index. The method assumes that all variables are normal independent of each other random variable, linear and only from the series, so with the actual deviation is Big. Therefore, people also improved the method, get the design checking point method, equivalent normal distribution method and the Lagrange multiplier method [3]. In recent years With the development of fuzzy mathematics, and finite element method, the fuzzy A new method of reliability based design and finite element reliability calculation, The calculation of the reliability is also a semi empirical and semi probabilistic method, approximate probability Method to the development of the full probability method is more accurate.In order to make the performance of drive axle is more excellent, more in line with people's life The requirements, including the design of half axle to axle, gear must be reliable Degree of consideration. In the reference [4], in order to achieve a reliable The drive axle housing of inner diameter, the late Bias statistical expectation Methods were summarized, the drive axle based on Bayesian statistics Reliability design of shell, and verified by examples. The results show that This method overcomes the shortcomings of the traditional method conservation, make the design more reasonable.Reference [5] introduces a reliability design in driving axle main reducer In the design, the main reducer single-stage Wheeled Construction Machinery The reliability optimization mathematical model and example analysis, the method To reduce the driving bridge size, save and improve the carrying capacity and the use of materials The conclusion has great practical significance of life. 3Modal analysis Modal analysis is a structural study of the vibration analysis One of the modern methods and means of advanced. It can be defined as the structure Analysis of the dynamic characteristics of the (finite element analysis) and experimental analysis (real Experimental modal analysis, the structural dynamic characteristics) using modal parameters to characterize the. In mathematics, the modal parameters are the differential equations of motion for mechanical systems The eigenvalues and eigenvectors; while in the experimental aspect, is measured Pole (natural frequency and damping) and the mode (modal vector). Modal analysis of characteristics and advantages of technology in power system Analysis, modal coordinates instead of physics coordinate, thereby greatly The number of degrees of freedom compression system analysis, analysis of high precision. For A large and complex system, such as cars, the sub structure analysis Method. It is the large structure complex for all sub structure, respectively Analysis of the finite element analysis and experimental modal substructure,get sub The dynamic model and the characteristic parameters of the structure, the sub structure according to the Methods to analyze integrated into a whole, is an effective reduction of self By the method of. Vibration characteristics of driving axle affects not only its own strong Degree, but also on the vehicle's ride comfort is important Influence. Therefore, drive on the bridge for the modal analysis, control and improve the Vibration characteristics, is one of the most important aspects in the design of. Reference [6] found a car through the modal analysis method Damage reason of drive axle. The car used in the central area of the drive axle housing Domain often cracks, calculations show that the bridge shell static stress distribution static strength Reasonable, destroy the static stress is small. Modal analysis of bridge shell Nine frequencies in the frequency range of the road spectrum, road surface spectrum excitation It is easy to cause resonance in the vertical direction. Forced vibration further divided The analysis results show, wherein certain parts of stress strength of materials is more than Limit, dynamic characteristics, dynamic strength is not good enough is generated to drive the bridge damage The fundamental reason. It not only shows the modal analysis method in the study of driving bridge With the application and design, but also the necessary. Because The traditional design and analysis method is not enough to solve the key components of a vehicle moving The strength state bearing. 4Modern optimization algorithms Modern optimization algorithms including neural network, ta bu search algorithm, die simulated annealing algorithm, genetic algorithm and Lagrange relaxation algorithm. This Some algorithms involved in biological evolution, artificial intelligence,mathematics and physics, God The system and statistical mechanics concepts, is a visual based the algorithm, called heuristic algorithm. The heuristic algorithm A close relationship with the formation of the theory of computational complexity. When people do not Satisfied with the conventional algorithm for solving complex problems,modern optimization algorithms began to reflect its role. Simulated annealing algorithm local search algorithm is extended, it is a global optimization algorithm, which can be applied to combinatorial optimization problems. Genetic algorithm is a random global search algorithm, the search automatic acquisition and accumulation of knowledge of space cable in the process, and the adaptive We should control the search process, so as to obtain the optimal or suboptimal solution. By in the genetic algorithm has the compatibility, it can be in accordance with the genetic algorithm and model The advantages of simulated annealing algorithm respectively, the combined tectonic genetic model Simulated annealing algorithm, multi objective of discrete and continuous design variables optimization design. In addition, the fuzzy mathematics and optimization is a combination of fuzzy optimization The algorithm, combined with the reliability engineering and Optimization Based on the reliability of the optimization algorithm. Can be expected, with the development of science and technology, the inevitable There will be new optimization algorithms, more advanced various. The design of the optimization algorithm is introduced and the components of the drive axle, can reduce component size, material saving, optimal transmission structure,optimization of transmission part parameters, make the design more scientific, reasonable. Reference [7]and [8] respectively with neural network, genetic algorithm for straight tooth and bevel gear transmission dynamic optimization, the objective function is the minimum volume of gear pair, reach satisfactory results. This shows that the driven application optimization algorithm Bridge structure of transmission parts size optimization design is feasible,efficient. 譯文： 驅(qū)動(dòng)橋是汽車總成中的重要承載件之一,其性能直接影響整車的性能和有效使用壽命。驅(qū)動(dòng)橋一般由橋殼、主減速器、差速器和半殼等元件組成,轉(zhuǎn)向驅(qū)動(dòng)橋還包括各種等速聯(lián)軸節(jié),結(jié)構(gòu)更復(fù)雜。傳統(tǒng)設(shè)計(jì)是以生產(chǎn)經(jīng)驗(yàn)為基礎(chǔ),以運(yùn)用力學(xué)、數(shù)學(xué)和回歸方法形成的公式、圖表、手冊(cè)等為依據(jù)進(jìn)行的?，F(xiàn)代設(shè)計(jì)是傳統(tǒng)設(shè)計(jì)的深入、豐富和發(fā)展,而非獨(dú)立于傳統(tǒng)設(shè)計(jì)的全新設(shè)計(jì)。以計(jì)算機(jī)技術(shù)為核心,以設(shè)計(jì)理論為指導(dǎo),是現(xiàn)代設(shè)計(jì)的主要特征。利用這種方法指導(dǎo)設(shè)計(jì)可以減小經(jīng)驗(yàn)設(shè)計(jì)的盲目性和隨意性,提高設(shè)計(jì)的主動(dòng)性、科學(xué)性和準(zhǔn)確性。同樣,對(duì)驅(qū)動(dòng)橋的研究不應(yīng)僅停留在傳統(tǒng)設(shè)計(jì)方法上,而應(yīng)借助于現(xiàn)代設(shè)計(jì)方法以精益求精。本文對(duì)研究驅(qū)動(dòng)橋所涉及的現(xiàn)代設(shè)計(jì)方法做了比較深入的研究,提出將各種設(shè)計(jì)方法互相結(jié)合,針對(duì)不同的設(shè)計(jì)內(nèi)容分別應(yīng)用不同的方法,以促進(jìn)其設(shè)計(jì)過(guò)程趨于合理化和科學(xué)化。 1　CAD/CAE技術(shù) CAD是利用計(jì)算機(jī)系統(tǒng)在工程和產(chǎn)品設(shè)計(jì)的各個(gè)階段為設(shè)計(jì)人員提供各種快速、有效的工具和手段,加快和優(yōu)化設(shè)計(jì)過(guò)程及設(shè)計(jì)結(jié)果,以達(dá)到最佳設(shè)計(jì)需要的技術(shù)。將CAD技術(shù)應(yīng)用于機(jī)械產(chǎn)品設(shè)計(jì),不但可以縮短設(shè)計(jì)周期,還可以提高設(shè)計(jì)的精確度和可靠性,從而實(shí)現(xiàn)設(shè)計(jì)過(guò)程的最佳化和自動(dòng)化。其發(fā)展呈開(kāi)放、集成及智能的趨勢(shì)。目前常用的三維CAD造型軟件有Pro/E、UG、MDT、Solid Works、AutoCAD等。Pro/E是一種CAD/CAE/CAM一體化的軟件系統(tǒng),具有強(qiáng)大的實(shí)體造型和表面造型功能,可構(gòu)造非常復(fù)雜的模型。產(chǎn)生的模型可形成裝配體,并能生成制造該模型零件的模具。無(wú)論零件模型、裝配體模型還是模具模型,都可轉(zhuǎn)化為二維工程圖。它采用單一的數(shù)據(jù)庫(kù),在任何階段都能自動(dòng)修改各階段的相應(yīng)數(shù)據(jù)。CAE方法中的有限元技術(shù)是計(jì)算數(shù)學(xué)、計(jì)算力學(xué)和計(jì)算工程科學(xué)領(lǐng)域里誕生的最有效的計(jì)算方法。有限元方法形態(tài)豐富,理論基礎(chǔ)完善,且已經(jīng)開(kāi)發(fā)出一批通用有限元程序,使用這些軟件可解決工程領(lǐng)域眾多的大型科學(xué)和計(jì)算難題,有限元計(jì)算結(jié)果已成為各類工業(yè)產(chǎn)品設(shè)計(jì)和性能分析的可靠依據(jù)。許多有限元分析程序?qū)⒂邢拊治?、?jì)算機(jī)圖形學(xué)與優(yōu)化技術(shù)結(jié)合起來(lái),形成完整的計(jì)算機(jī)輔助分析系統(tǒng),可顯著提高產(chǎn)品設(shè)計(jì)性能,縮短設(shè)計(jì)周期,增強(qiáng)產(chǎn)品的競(jìng)爭(zhēng)力。在眾多有限元分析商業(yè)軟件中,ANSYS是最通用有效的軟件之一,它擁有豐富和完善的單元庫(kù)、材料模型庫(kù)和求解器,確保高效地求解各類結(jié)構(gòu)的靜力、動(dòng)力、振動(dòng)、線性和非線性問(wèn)題以及熱分析和熱-結(jié)構(gòu)耦合問(wèn)題,其高級(jí)分析技術(shù)還能進(jìn)行參數(shù)化設(shè)計(jì)、優(yōu)化設(shè)計(jì)和拓?fù)鋬?yōu)化等。CAD/CAE技術(shù)在驅(qū)動(dòng)橋的研究和設(shè)計(jì)中大有用武之地。對(duì)于新產(chǎn)品,用CAD造出驅(qū)動(dòng)橋各個(gè)元件的實(shí)體模型,用CAE對(duì)這些模型進(jìn)行計(jì)算,檢驗(yàn)其性能是否滿足要求。如果不滿足要求可修改模型,直到滿意為止。最后將模型轉(zhuǎn)化為工程圖,便可制造產(chǎn)品。如果將CAD/CAE與CAM或快速成型技術(shù)結(jié)合起來(lái),能顯著縮短從設(shè)計(jì)到制造的整個(gè)產(chǎn)品周期,還可生成現(xiàn)有零件的零件庫(kù),以方便相似或系列驅(qū)動(dòng)橋的設(shè)計(jì)。當(dāng)然,對(duì)已有零件進(jìn)行強(qiáng)度和失效分析以及改進(jìn)也會(huì)經(jīng)常用到這種方法。在分析某微型車專用驅(qū)動(dòng)橋殼的破壞原因時(shí),參考文獻(xiàn)[1]采用了CAD/CAE方法。先用三維CAD造型軟件Deas建造該橋殼的模型,然后用有限元方法進(jìn)行計(jì)算,發(fā)現(xiàn)局部區(qū)域出現(xiàn)應(yīng)力集中,該區(qū)域與破壞區(qū)域吻合。采用不同方案對(duì)模型進(jìn)行修改,并計(jì)算修改后模型的應(yīng)力分布,找到了較好的改善方案。改進(jìn)后的驅(qū)動(dòng)橋使用情況良好。 參考文獻(xiàn)[2]則將CAD/CAE技術(shù)與C語(yǔ)言相結(jié)合,利用C語(yǔ)言中的“類”對(duì)系統(tǒng)控制模塊和功能模塊元素及成員函數(shù)進(jìn)行封裝,得到優(yōu)化的系列驅(qū)動(dòng)橋產(chǎn)品數(shù)據(jù)模型,最大限度地利用了現(xiàn)有設(shè)計(jì)資源。 2　可靠性工程 可靠性工程以概率和隨機(jī)分布為基礎(chǔ),研究各種結(jié)構(gòu)在規(guī)定條件和規(guī)定時(shí)間內(nèi),完成規(guī)定功能的概率。人們對(duì)隨機(jī)現(xiàn)象的研究由來(lái)已久,但其在工程中的應(yīng)用卻并非相伴而生。傳統(tǒng)設(shè)計(jì)認(rèn)為材料本身的性能(強(qiáng)度、韌性和硬度等)和所受到的應(yīng)力都是常量,以此為指導(dǎo)的產(chǎn)品偏于保守?？紤]隨機(jī)性并在設(shè)計(jì)中引入可靠度,更真實(shí)地反映了客觀現(xiàn)實(shí),由此設(shè)計(jì)出的產(chǎn)品也更科學(xué)、合理?，F(xiàn)在,一些發(fā)達(dá)國(guó)家設(shè)計(jì)制造的某些零件,其壽命可以精確到小時(shí),如果沒(méi)有可靠性計(jì)算,是不可想象的。機(jī)械結(jié)構(gòu)常用的可靠度計(jì)算方法是一次二階矩法。該法將狀態(tài)函數(shù)(強(qiáng)度與應(yīng)力之差)在均值點(diǎn)處按泰勒級(jí)數(shù)展開(kāi),忽略二次以上項(xiàng),便可得到可靠度指標(biāo)。由于該法假設(shè)各個(gè)變量均為相互獨(dú)立的正態(tài)隨機(jī)變量,且只取級(jí)數(shù)的線性項(xiàng),故與實(shí)際偏差較大。為此,人們又改進(jìn)了這種方法,得到設(shè)計(jì)驗(yàn)算點(diǎn)法、等效正態(tài)分布法和拉格朗日乘子法等[3]。近年來(lái),隨著模糊數(shù)學(xué)和有限元技術(shù)的發(fā)展,出現(xiàn)了模糊可靠度設(shè)計(jì)和基于可靠度的有限元計(jì)算等新方法,可靠度本身的計(jì)算也由半經(jīng)驗(yàn)半概率法、近似概率法發(fā)展到更精確的全概率法。 為了使驅(qū)動(dòng)橋的性能更優(yōu)良,壽命更符合人們的要求,包括橋殼、齒輪到半軸的設(shè)計(jì)都必須將可靠度考慮進(jìn)去。在參考文獻(xiàn)[4]中,為了實(shí)現(xiàn)給定可靠度求出驅(qū)動(dòng)橋殼內(nèi)徑,作者對(duì)貝葉斯統(tǒng)計(jì)后期期望方法進(jìn)行了整理,得到了基于貝葉斯統(tǒng)計(jì)的驅(qū)動(dòng)橋殼的可靠性設(shè)計(jì),并通過(guò)例子予以驗(yàn)證。結(jié)果表明該方法克服了傳統(tǒng)方法的保守性,使設(shè)計(jì)更合理。參考文獻(xiàn)[5]介紹了可靠性設(shè)計(jì)在驅(qū)動(dòng)橋主減速器設(shè)計(jì)中的應(yīng)用,給出了單級(jí)輪式工程機(jī)械主減速器的可靠性優(yōu)化數(shù)學(xué)模型和算例分析,得出了該方法對(duì)減小驅(qū)動(dòng)橋尺寸、節(jié)省材料、提高承載能力和使用壽命具有較大實(shí)際意義的結(jié)論。 3　模態(tài)分析 模態(tài)分析是對(duì)工程結(jié)構(gòu)進(jìn)行振動(dòng)分析研究的最先進(jìn)的現(xiàn)代方法與手段之一。它可以定義為對(duì)結(jié)構(gòu)動(dòng)態(tài)特性的解析分析(有限元分析)和實(shí)驗(yàn)分析(實(shí)驗(yàn)?zāi)B(tài)分析),其結(jié)構(gòu)動(dòng)態(tài)特性用模態(tài)參數(shù)來(lái)表征。在數(shù)學(xué)上,模態(tài)參數(shù)是力學(xué)系統(tǒng)運(yùn)動(dòng)微分方程的特征值和特征向量;而在實(shí)驗(yàn)方面,則是測(cè)得的系統(tǒng)的極點(diǎn)(固有頻率和阻尼)和振型(模態(tài)向量)。模態(tài)分析技術(shù)的特點(diǎn)與優(yōu)點(diǎn)是在對(duì)系統(tǒng)做動(dòng)力學(xué)分析時(shí),用模態(tài)坐標(biāo)代替物理學(xué)坐標(biāo),從而可大大壓縮系統(tǒng)分析的自由度數(shù)目,分析精度較高。對(duì)于大型復(fù)雜的系統(tǒng),比如汽車,可采用子結(jié)構(gòu)分析方法。它是把復(fù)雜的大型結(jié)構(gòu)劃分為各子結(jié)構(gòu),分別對(duì)子結(jié)構(gòu)進(jìn)行有限元分析或?qū)嶒?yàn)?zāi)B(tài)分析,取得子結(jié)構(gòu)的動(dòng)力模型及其特性參數(shù),再將子結(jié)構(gòu)按照一定方法綜合成一整體進(jìn)行分析,是一種有效縮減自由度的方法。驅(qū)動(dòng)橋的振動(dòng)特性不但直接影響其本身的強(qiáng)度,而且對(duì)整車的舒適性和平順性有著至關(guān)重要的影響。因此,對(duì)驅(qū)動(dòng)橋進(jìn)行模態(tài)分析,掌握和改善其振動(dòng)特性,是設(shè)計(jì)中的重要方面。參考文獻(xiàn)[6]通過(guò)模態(tài)分析方法找到了某汽車驅(qū)動(dòng)橋的破壞原因。該車使用中其驅(qū)動(dòng)橋殼中部區(qū)域常出現(xiàn)裂紋,靜強(qiáng)度計(jì)算表明該橋殼靜應(yīng)力分布合理,破壞區(qū)的靜應(yīng)力很小。模態(tài)分析中橋殼的前九階頻率在路面譜頻率范圍內(nèi),在路面譜的激勵(lì)下很容易引起垂直方向的共振。進(jìn)一步的強(qiáng)迫振動(dòng)分析表明,其中部某些部位應(yīng)力超過(guò)了材料的強(qiáng)度極限,動(dòng)態(tài)特性不好、動(dòng)強(qiáng)度不足是產(chǎn)生驅(qū)動(dòng)橋破壞的根本原因。這不但說(shuō)明模態(tài)分析方法在驅(qū)動(dòng)橋研究和設(shè)計(jì)中有著具體的應(yīng)用,而且還是必要的。因?yàn)閭鹘y(tǒng)設(shè)計(jì)和分析方法不足以解決汽車關(guān)鍵部件的動(dòng)態(tài)承載強(qiáng)度問(wèn)題。 4　優(yōu)化算法 現(xiàn)代優(yōu)化算法包括神經(jīng)網(wǎng)絡(luò)、禁忌搜索算法、模擬退火算法、遺傳算法和拉格朗日松弛算法等。這些算法涉及生物進(jìn)化、人工智能、數(shù)學(xué)和物理學(xué)、神經(jīng)系統(tǒng)和統(tǒng)計(jì)力學(xué)等概念,是以一定的直觀為基礎(chǔ)構(gòu)造的算法,稱之為啟發(fā)式算法。啟發(fā)式算法的興起與計(jì)算復(fù)雜性理論的形成有密切關(guān)系。當(dāng)人們不滿足于常規(guī)算法求解復(fù)雜問(wèn)題時(shí),現(xiàn)代優(yōu)化算法開(kāi)始體現(xiàn)其作用。模擬退火算法是局部搜索算法的擴(kuò)展,它是一種全局最優(yōu)算法,可應(yīng)用于組合最優(yōu)化問(wèn)題。遺傳算法是一種隨機(jī)的全局搜索算法,能在搜索過(guò)程中自動(dòng)獲取和積累有關(guān)空間的知識(shí),并自適應(yīng)地控制搜索過(guò)程,從而得到最優(yōu)解或次優(yōu)解。由于遺傳算法具有兼容性,因此可根據(jù)遺傳算法和模擬退火算法各自的優(yōu)點(diǎn),將兩者相結(jié)合構(gòu)造遺傳模擬退火算法,對(duì)離散與連續(xù)的設(shè)計(jì)變量進(jìn)行多目標(biāo)優(yōu)化設(shè)計(jì)。另外,模糊數(shù)學(xué)和優(yōu)化相結(jié)合產(chǎn)生了模糊優(yōu)化算法,可靠性工程和優(yōu)化的結(jié)合則產(chǎn)生基于可靠性的優(yōu)化算法?？梢灶A(yù)見(jiàn),隨著科學(xué)技術(shù)的發(fā)展,必然會(huì)出現(xiàn)各種新型的、更先進(jìn)的優(yōu)化算法。將優(yōu)化算法引入驅(qū)動(dòng)橋及各元件的設(shè)計(jì),可以減小部件體積、節(jié)省材料、優(yōu)化傳動(dòng)結(jié)構(gòu)、優(yōu)化傳動(dòng)零件的參數(shù),使其設(shè)計(jì)更科學(xué)、合理。參考文獻(xiàn)[7]和[8]分別用神經(jīng)網(wǎng)絡(luò)、遺傳算法對(duì)直齒和斜齒輪傳動(dòng)進(jìn)行了優(yōu)化,以齒輪副體積最小為目標(biāo)函數(shù),達(dá)到了令人滿意的結(jié)果。這表明應(yīng)用優(yōu)化算法進(jìn)行驅(qū)動(dòng)橋傳動(dòng)零件結(jié)構(gòu)尺寸優(yōu)化設(shè)計(jì)可行、高效。 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