發(fā)布時(shí)間：2018-02-24 13:52

  本文關(guān)鍵詞： 自由曲面 B樣條 建筑邊界 應(yīng)變能敏感度　出處：《哈爾濱工業(yè)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著社會(huì)文明的發(fā)展,建筑的活動(dòng)空間在不斷的改善和擴(kuò)充,人們?cè)絹碓接X得固有的建筑形式選擇范圍有限,不能滿足日益發(fā)展的對(duì)建筑表現(xiàn)力的要求。自由曲面結(jié)構(gòu)造型美觀,具有強(qiáng)烈的視覺沖擊效果,能夠生成多種多樣靈活多變的幾何形狀來滿足建筑設(shè)計(jì)上的要求。如何建立合理的自由曲面結(jié)構(gòu)形態(tài)創(chuàng)構(gòu)方法,是目前需要解決的主要問題。本文針對(duì)在實(shí)際工程中可能存在的多種復(fù)雜內(nèi)外建筑邊界條件,利用B樣條曲線理論,引用Delaunay三角剖分技術(shù)對(duì)平面設(shè)計(jì)域進(jìn)行三角剖分,投影到B樣條曲面上,建立了具有復(fù)雜設(shè)計(jì)域的自由曲面初始模型,提出了利用少數(shù)關(guān)鍵點(diǎn)來調(diào)整曲面形狀的自由曲面結(jié)構(gòu)形態(tài)創(chuàng)構(gòu)方法。主要包括以下內(nèi)容:1.創(chuàng)建自由曲面結(jié)構(gòu)初始模型初始模型的建立是自由曲面結(jié)構(gòu)形態(tài)創(chuàng)構(gòu)的基礎(chǔ),本文基于B樣條曲線理論,利用奇次周期參數(shù)化B樣條曲線,生成多種次數(shù)、多條曲線共同組成建筑外邊界和內(nèi)邊界,充分滿足建筑設(shè)計(jì)上對(duì)于邊界造型豐富、內(nèi)部預(yù)留孔洞的要求,在工程實(shí)際方面有更強(qiáng)的實(shí)用性;2.確定評(píng)價(jià)目標(biāo)函數(shù)在優(yōu)化過程中,需要對(duì)每一步得到的優(yōu)化結(jié)果進(jìn)行評(píng)價(jià),評(píng)價(jià)的內(nèi)容需要綜合考慮結(jié)構(gòu)整體受力情況,評(píng)價(jià)的目標(biāo)函數(shù)與變量之間的關(guān)系應(yīng)該是能夠用程序來實(shí)現(xiàn),而且表達(dá)式應(yīng)盡可能簡單,提高計(jì)算效率。本文采用應(yīng)變能作為評(píng)價(jià)指標(biāo),應(yīng)變能能夠綜合反應(yīng)結(jié)構(gòu)的整體力學(xué)性能,通過對(duì)應(yīng)變能的單目標(biāo)優(yōu)化來尋找力學(xué)性能合理的結(jié)構(gòu)。在進(jìn)化過程中,保證結(jié)構(gòu)的整體剛度增大,最終以薄膜內(nèi)力的方式傳遞荷載;3.建立結(jié)構(gòu)形態(tài)優(yōu)化方法為了得到合理的結(jié)構(gòu)形態(tài),需要將自由曲面的幾何創(chuàng)建方法與結(jié)構(gòu)形態(tài)優(yōu)化算法結(jié)合起來,通過對(duì)曲面形狀決定參數(shù)的優(yōu)化調(diào)整,逐步得到造型美觀且受力合理的自由曲面。本文首先詳細(xì)推導(dǎo)了B樣條曲面上關(guān)鍵點(diǎn)的應(yīng)變能敏感度的表達(dá)式,給定步長,對(duì)曲面上關(guān)鍵點(diǎn)縱坐標(biāo)在敏感度負(fù)梯度方向上進(jìn)行調(diào)整,使得到的最終結(jié)構(gòu)應(yīng)變能達(dá)到較低水平,且敏感度趨于零,此時(shí)自由曲面結(jié)構(gòu)達(dá)到相對(duì)合理的受力狀態(tài)。利用本文建立的方法得到的自由曲面結(jié)構(gòu)表面光滑連續(xù),無需二次加工,而且只需要計(jì)算曲面上關(guān)鍵點(diǎn)的應(yīng)變能敏感度,計(jì)算量小,計(jì)算效率高。同時(shí),曲面邊界多樣,凹凸豐富。該方法不僅僅是更加深入的理論研究,同時(shí)具有很高的工程實(shí)用性。
[Abstract]:With the development of social civilization and the continuous improvement and expansion of the active space of architecture, people increasingly feel that the scope of choice of inherent architectural forms is limited. Can not meet the growing demands of architectural expressiveness. The free-form structure is beautiful and has a strong visual impact effect. Can produce a variety of flexible geometric shapes to meet the requirements of architectural design. It is the main problem that needs to be solved at present. In view of many complex interior and outer building boundary conditions that may exist in practical engineering, this paper applies B-spline curve theory and Delaunay triangulation technology to triangulate the plane design domain. The initial model of free-form surface with complex design domain is established by projecting onto B-spline surface. In this paper, a new method of free-form structure is proposed, which uses a few key points to adjust the shape of surface. The main contents are as follows: 1. The establishment of the initial model of free-form surface structure is the foundation of free-form structure formation. Based on the theory of B-spline curve, this paper makes use of the odd periodic parameterized B-spline curve to generate a variety of times and many curves together to form the outer and inner boundary of the building, which fully satisfies the rich boundary modeling in architectural design. The requirement of internal reservation of holes is more practical in engineering practice 2.To determine the evaluation objective function in the process of optimization, it is necessary to evaluate the optimization results obtained from each step. The contents of the evaluation need to take into account the overall stress of the structure, the relationship between the objective function of the evaluation and the variables should be realized by program, and the expression should be as simple as possible. In this paper, strain energy is used as the evaluation index. Strain energy can synthesize the overall mechanical properties of the reaction structure, and the structure with reasonable mechanical properties can be found by the single objective optimization of the strain energy. To ensure the increase of the overall stiffness of the structure, and finally transfer the load by the internal force of the membrane. 3. In order to obtain the reasonable structure shape, it is necessary to combine the geometric creating method of the free form surface with the structural shape optimization algorithm. By optimizing and adjusting the shape of the surface to determine the parameters, the free-form surface with beautiful shape and reasonable force is gradually obtained. In this paper, the expression of strain energy sensitivity of the key points on the B-spline surface is derived in detail, and the step size is given. The vertical coordinates of the key points on the surface are adjusted in the direction of negative sensitivity gradient so that the final structural strain can reach a lower level and the sensitivity tends to zero. The surface of the free-form surface is smooth and continuous, no secondary machining is required, and the sensitivity of strain energy of the key points on the surface is only calculated. At the same time, the surface boundary is diverse, and the concave and convex surface is rich. This method is not only a more in-depth theoretical study, but also has high engineering practicability.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU318

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本文編號(hào)：1530478