等幾何分析中的NURBS體造型及算法
發(fā)布時(shí)間：2018-08-01 18:45
【摘要】：在傳統(tǒng)的有限元分析過(guò)程中， CAD（幾何設(shè)計(jì)模型）與CAE（分析模型）分別在兩個(gè)軟件平臺(tái)中實(shí)現(xiàn)，，即通過(guò)CAD系統(tǒng)建立幾何模型，然后將設(shè)計(jì)模型導(dǎo)入CAE軟件平臺(tái)中產(chǎn)生分析模型。在上述轉(zhuǎn)化過(guò)程中，需對(duì)幾何模型進(jìn)行細(xì)節(jié)移除、模型簡(jiǎn)化、降維等一系列的處理以生成分析模型，進(jìn)行有限元分析。即從CAD到CAE的過(guò)程中沒(méi)有實(shí)現(xiàn)設(shè)計(jì)模型與分析模型的真正統(tǒng)一。設(shè)計(jì)者總是希望分析過(guò)程盡量簡(jiǎn)潔和智能，減少人工干預(yù)對(duì)設(shè)計(jì)方案的修改和優(yōu)化。 在現(xiàn)今的CAE分析中，由于上述的設(shè)計(jì)和分析模型的不統(tǒng)一造成了CAE結(jié)果在此過(guò)程中作用有限，因此希望能將CAE分析結(jié)果智能地反饋到設(shè)計(jì)系統(tǒng)中以進(jìn)行自動(dòng)干預(yù)，實(shí)現(xiàn)CAE/CAD模型間自動(dòng)反饋。為解決這個(gè)問(wèn)題，必須使設(shè)計(jì)模型與分析模型統(tǒng)一，實(shí)現(xiàn)CAD和CAE之間的雙向映射，即CAD/CAE間的無(wú)縫集成。 本文探索性地利用了基于NURBS原理的等幾何分析，通過(guò)NURBS強(qiáng)大的幾何造型功能實(shí)現(xiàn)對(duì)實(shí)體模型的構(gòu)造。NURBS（非均勻有理B樣條）基函數(shù)通過(guò)線性組合生成精確描述的幾何模型，再利用NURBS節(jié)點(diǎn)插值和基函數(shù)的階數(shù)升降的方法來(lái)產(chǎn)生相應(yīng)的有限元模型，而在此過(guò)程中節(jié)點(diǎn)插值并不會(huì)改變幾何模型形狀。此種方法徹底摒棄了傳統(tǒng)有限元分析中利用網(wǎng)格生成器來(lái)生成近似分析模型的方法，實(shí)現(xiàn)了真正意義上的設(shè)計(jì)反饋和模型統(tǒng)一。 本文主要介紹了等幾何分析的相關(guān)理論，探索了在此理論下NURBS基本算法和體造型算法。本文應(yīng)用基于三元參數(shù)的NURBS造型技術(shù)，通過(guò)質(zhì)心參數(shù)化，模型中軸線提取等一系列處理過(guò)程，生成了高精度的NURBS體網(wǎng)格。在此基礎(chǔ)上通過(guò)節(jié)點(diǎn)插值和對(duì)基函數(shù)的升階實(shí)現(xiàn)了網(wǎng)格劃分與單元生成。生成的模型具有網(wǎng)格質(zhì)量均勻、單元連續(xù)性高的特點(diǎn)。論文最后利用VC++開發(fā)了軟件系統(tǒng)，實(shí)現(xiàn)了上述等幾何分析算法及NURBS體造型。
[Abstract]:In the traditional finite element analysis process, the, CAD (geometric design model and the CAE (analysis model) are implemented in two software platforms, namely, the geometric model is built through CAD system, and then the design model is imported into the CAE software platform to produce the analysis model. In the process of transformation, the geometric model should be removed in detail, simplified and dimensionally reduced to generate an analytical model for finite element analysis. That is, the process from CAD to CAE does not realize the real unity of design model and analysis model. The designer always wants the analysis process to be as concise and intelligent as possible, and to reduce the modification and optimization of the design scheme by manual intervention. In today's CAE analysis, due to the disunity of the above design and analysis model, the result of CAE is limited in this process, so it is hoped that the results of CAE analysis can be intelligently fed back to the design system for automatic intervention. Automatic feedback between CAE/CAD models is realized. In order to solve this problem, we must unify the design model with the analysis model, and realize the two-way mapping between CAD and CAE, that is, the seamless integration between CAD/CAE. In this paper, the isometric analysis based on NURBS principle is used to realize the construction of entity model. Nurbs (nonuniform rational B-spline) basis function is constructed by the powerful geometric modeling function of NURBS. The corresponding finite element model is generated by using the NURBS node interpolation and the order rise and fall of the basis function, but in the process the node interpolation does not change the shape of the geometric model. This method completely abandons the traditional method of generating approximate analysis model by using mesh generator in finite element analysis and realizes the design feedback and model unification in real sense. This paper mainly introduces the theory of isometric analysis, and explores the basic algorithm of NURBS and the algorithm of volume modeling under this theory. In this paper, NURBS modeling technology based on ternary parameters is applied to generate a high-precision NURBS volume mesh through a series of processing processes such as centroid parameterization and axis extraction in the model. On this basis, mesh generation and cell generation are realized by node interpolation and raising the order of the basis function. The generated model has the characteristics of uniform mesh quality and high cell continuity. Finally, the software system is developed by using VC, and the above isometric analysis algorithm and NURBS body modeling are realized.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：TH122;TB115
[Abstract]:In the traditional finite element analysis process, the, CAD (geometric design model and the CAE (analysis model) are implemented in two software platforms, namely, the geometric model is built through CAD system, and then the design model is imported into the CAE software platform to produce the analysis model. In the process of transformation, the geometric model should be removed in detail, simplified and dimensionally reduced to generate an analytical model for finite element analysis. That is, the process from CAD to CAE does not realize the real unity of design model and analysis model. The designer always wants the analysis process to be as concise and intelligent as possible, and to reduce the modification and optimization of the design scheme by manual intervention. In today's CAE analysis, due to the disunity of the above design and analysis model, the result of CAE is limited in this process, so it is hoped that the results of CAE analysis can be intelligently fed back to the design system for automatic intervention. Automatic feedback between CAE/CAD models is realized. In order to solve this problem, we must unify the design model with the analysis model, and realize the two-way mapping between CAD and CAE, that is, the seamless integration between CAD/CAE. In this paper, the isometric analysis based on NURBS principle is used to realize the construction of entity model. Nurbs (nonuniform rational B-spline) basis function is constructed by the powerful geometric modeling function of NURBS. The corresponding finite element model is generated by using the NURBS node interpolation and the order rise and fall of the basis function, but in the process the node interpolation does not change the shape of the geometric model. This method completely abandons the traditional method of generating approximate analysis model by using mesh generator in finite element analysis and realizes the design feedback and model unification in real sense. This paper mainly introduces the theory of isometric analysis, and explores the basic algorithm of NURBS and the algorithm of volume modeling under this theory. In this paper, NURBS modeling technology based on ternary parameters is applied to generate a high-precision NURBS volume mesh through a series of processing processes such as centroid parameterization and axis extraction in the model. On this basis, mesh generation and cell generation are realized by node interpolation and raising the order of the basis function. The generated model has the characteristics of uniform mesh quality and high cell continuity. Finally, the software system is developed by using VC, and the above isometric analysis algorithm and NURBS body modeling are realized.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：TH122;TB115
【相似文獻(xiàn)】
相關(guān)期刊論文 前10條
1 蘇
本文編號(hào)：2158499
本文鏈接：http://www.lk138.cn/kejilunwen/jixiegongcheng/2158499.html
最近更新
教材專著
