本文選題：振沖器 + 土力學��； 參考：《陜西科技大學》2015年碩士論文

【摘要】：近幾年建筑行業(yè)發(fā)展較快,為了能夠讓建筑物具有穩(wěn)定性,這就要求對地基的穩(wěn)定性及抗震性有很高的要求。振沖器是一種壓實土壤的器械,成為了現(xiàn)代建筑行業(yè)的主要施工機械,而有效的對土壤壓實已成為目前國內外研究的重點。土壤具有十分復雜的非線性特點,而且是非連續(xù)體,因此對于振沖器與土壤耦合分析是很有必要的。課題對土壤的物理性能進行理論分析:研究土壤力學、土壤及其壓實性能,對土壤的三相指標與壓實的有關指標進行分析。最終確立選擇土壤動力本構模型為Drucker-Prager模型,此模型是在考慮靜水壓力廣義的Mises屈服準則基礎上建立起來的。課題以功率為75KW的振沖器為研究對象,介紹振沖器的主要結構及工作原理,之后對振沖器進行力學分析,在振動壓實數(shù)學模型及動力學方程的基礎上,得到了振沖器加速度與土壤緊密程度的力學關系。通過分析振沖器壓實土壤的過程,得到土壤的塑性變形比較大,因此把土壤變形忽略而簡化振沖器動力學分析的做法與實際情況是不符的。為了深入研究振沖器運動機理,對振沖器工作情況及結構進行分析研究,提取主要結構參數(shù)。在合理簡化振沖器的動力學模型基礎上,將振沖器的工作過程分為三個階段來研究,并建立相應的動力學模型,得到振沖器工作階段的動力學方程,最后得出系統(tǒng)方程組的解析解表達式。現(xiàn)場觀察了振沖器結構并獲取各結構的具體尺寸,運用Soild Works對振沖器進行三維建模。對各結構進行面與面的裝配,得到振沖器整體的三維模型。在工作中水通過噴射管后由振沖頂尖噴出。高壓的水流會對振沖器頂尖產生影響,流體與振沖器頂尖產生了復雜的流固耦合。針對這種現(xiàn)象用ANSYS單向流固耦合(FSI)分析,得出了水流對振沖器頂尖應力的影響。分析結果對于振沖器頂尖的工作結構及維護有一定的指導意義。對振沖器三維模型進行簡化處理。之后定義材料屬性、網格劃分、約束方式,得到有限元模型,使用ANSYS軟件對其進行模態(tài)分析,得出振沖器前6階固有頻率及固有振形。從而知道振沖器在工作時共振發(fā)生在哪個部位上,在后續(xù)的工作中使得振沖器避開共振頻率工作,這樣能夠讓振沖器的壽命提高。最后利用軟件ANSYS/LS-DYNA來分析振沖器與土壤的耦合模型,在LS-PREPOST后處理軟件中進行可視化后處理,得到二者的等效應力分布、接觸力等情況。
[Abstract]:In recent years, the construction industry has developed rapidly. In order to make buildings have stability, it is necessary to have high requirements for foundation stability and seismic resistance. Vibrator is a kind of equipment for compacting soil, which has become the main construction machinery in modern construction industry, and the effective compaction of soil has become the focus of research at home and abroad. Soil has very complex nonlinear characteristics and is discontinuous, so it is necessary for the coupled analysis of vibrator and soil. In this paper, the physical properties of soil are analyzed theoretically: soil mechanics, soil and compaction properties are studied, and the three-phase index and compaction index of soil are analyzed. Finally, the soil dynamic constitutive model is chosen as Drucker-Prager model, which is based on the generalized Mises yield criterion of hydrostatic pressure. The main structure and working principle of the vibrator are introduced, and then the mechanical analysis of the vibrator is carried out. Based on the mathematical model and dynamic equation of vibration compaction, the main structure and working principle of the vibrator are introduced. The mechanical relationship between vibrator acceleration and soil compactness is obtained. By analyzing the process of compacting soil with vibrator, it is found that the plastic deformation of soil is relatively large, so the method of simplifying the dynamic analysis of vibrator by neglecting soil deformation does not accord with the actual situation. In order to study the motion mechanism of vibrator, the working condition and structure of vibrator were analyzed and the main structural parameters were extracted. On the basis of reasonably simplifying the dynamic model of the vibrator, the working process of the vibrator is divided into three stages to study, and the corresponding dynamic model is established, and the dynamic equation of the vibrator working phase is obtained. Finally, the analytical solution of the system equations is obtained. The vibrator structure was observed and the specific dimensions of each structure were obtained, and Soild Works was used to model the vibrator. The three-dimensional model of the vibrator is obtained by assembling the surfaces of each structure. At work, water is ejected through the jet tube by the vibrating tip. The flow of high pressure affects the center of vibrator, and the fluid and the center of vibrator produce complex fluid-solid coupling. In view of this phenomenon, the influence of water flow on the tip stress of vibrator is obtained by using ANSYS unidirectional fluid-solid coupling analysis. The analysis results have certain guiding significance for the working structure and maintenance of the vibrator center. The three-dimensional model of vibrator is simplified. The finite element model is obtained by defining the material attribute, mesh division and constraint mode. The modal analysis of the finite element model is carried out by using ANSYS software, and the first 6 natural frequencies and natural vibration shapes of the vibrator are obtained. In order to know which part of the vibrator resonance occurs in the operation, in the subsequent work, the vibrator can avoid the resonant frequency operation, which can improve the life of the vibrator. Finally, the coupling model between vibrator and soil is analyzed by software ANSYS/LS-DYNA, and the equivalent stress distribution and contact force are obtained by visual post-processing in LS-PREPOST post-processing software.
【學位授予單位】：陜西科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU435

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本文編號：1794681