本文選題：計(jì)算本構(gòu)模型　切入點(diǎn)：數(shù)值模擬　出處：《中國科學(xué)技術(shù)大學(xué)》2013年博士論文　論文類型：學(xué)位論文

【摘要】：混凝土作為一種建筑材料在國防和土木工程中得到了廣泛的應(yīng)用,研究混凝土結(jié)構(gòu)在彈體沖擊或炸藥爆炸作用下的響應(yīng)和破壞問題對武器和防護(hù)結(jié)構(gòu)的設(shè)計(jì)具有重要意義。本文的主要工作是建立混凝土動態(tài)計(jì)算本構(gòu)新模型,并將其應(yīng)用于混凝土靶板在彈丸高速撞擊下的侵徹問題和炸藥爆炸載荷作用下的響應(yīng)問題中,成功預(yù)測了彈體的侵徹深度、殘余速度、減加速度以及混凝土靶板中裂紋的擴(kuò)展和演化過程。本文主要包括以下幾個(gè)方面的內(nèi)容： 在現(xiàn)有混凝土本構(gòu)模型和一些最新實(shí)驗(yàn)數(shù)據(jù)的基礎(chǔ)上,發(fā)展混凝土動態(tài)計(jì)算本構(gòu)新模型。該模型能反映混凝土材料的基本特性如壓力相關(guān)性,應(yīng)變率相關(guān)性,應(yīng)變軟化,加載路徑相關(guān)性,多孔性以及高低圍壓下的損傷等。針對混凝土材料的拉伸損傷,本文引入拉伸主應(yīng)變損傷法則來描述混凝土材料的拉伸開裂行為。對于混凝土材料的動態(tài)強(qiáng)度,本文在分析了現(xiàn)有混凝土壓縮和拉伸動態(tài)材料實(shí)驗(yàn)數(shù)據(jù)后,在兩個(gè)假設(shè)的基礎(chǔ)上,提出了新的混凝土動態(tài)增強(qiáng)因子(DIF)的經(jīng)驗(yàn)公式。此模型的兩個(gè)假設(shè)是：慣性效應(yīng)只對混凝土材料的動態(tài)壓縮強(qiáng)度有影響,對動態(tài)拉伸強(qiáng)度沒有影響；在相同的應(yīng)變率條件下,混凝土材料的動態(tài)壓縮強(qiáng)度增量與動態(tài)拉伸強(qiáng)度增量相同。我們將采用單單元模型的數(shù)值計(jì)算來驗(yàn)證本構(gòu)模型的正確性。 對卵形彈高速侵徹鋼筋混凝土靶板進(jìn)行數(shù)值模擬。本文對卵形彈貫穿48MPa、140MPa、38MPa有限厚度混凝土靶板,以及卵形彈侵徹39MPa半無限混凝土靶板進(jìn)行了數(shù)值模擬,并將數(shù)值模擬得到的殘余速度、侵徹深度和(減)加速度結(jié)果與實(shí)驗(yàn)數(shù)據(jù)進(jìn)行了比較,發(fā)現(xiàn)兩者吻合得較好。同時(shí),數(shù)值模擬還揭示了混凝土靶板在卵形彈彈體貫穿過程中裂紋的演化過程,數(shù)值模擬中得到的開坑直徑和漏斗坑直徑與實(shí)驗(yàn)數(shù)據(jù)也吻合得較好。 對平頭彈以不同速度撞擊鋼筋混凝土靶板進(jìn)行數(shù)值模擬。數(shù)值模擬得到的混凝土靶板裂紋形貌與實(shí)驗(yàn)照片吻合得較好。同時(shí),對平頭彈撞擊混凝土靶板進(jìn)行了參數(shù)研究,分析了平頭彈撞擊速度,平頭彈直徑和質(zhì)量,混凝土靶板厚度和直徑對混凝土靶板中裂紋演化的影響,得到了一些有益的結(jié)論。 對炸藥爆炸載荷作用下鋼筋混凝土的響應(yīng)和破壞進(jìn)行數(shù)值模擬。模擬了炸藥接觸爆炸和炸藥處于封閉空間內(nèi)的爆炸問題。數(shù)值模擬得到的混凝土靶板的裂紋形貌與實(shí)驗(yàn)觀察進(jìn)行了比較,兩者吻合得較好。同時(shí),對混凝土接觸爆炸問題進(jìn)行了參數(shù)研究,分析了不同厚度不同直徑混凝土靶板對裂紋演化的影響。 將Hoek-Brown破壞準(zhǔn)則引入空穴膨脹理論,并對混凝土靶板的侵徹問題進(jìn)行數(shù)值計(jì)算。首先將Hoek-Brown破壞準(zhǔn)則和彈性-脆性-理想塑性應(yīng)力應(yīng)變關(guān)系引入到球形空穴膨脹理論中,用以描述混凝土材料的本構(gòu)關(guān)系和破壞過程,彌補(bǔ)了以往的空穴膨脹理論中混凝土材料本構(gòu)較為簡單的缺陷。本構(gòu)模型抓住了混凝土材料的基本力學(xué)行為,如壓力相關(guān)性,應(yīng)變軟化,能較真實(shí)地反映混凝土材料的力學(xué)行為。本文通過數(shù)值計(jì)算的方法預(yù)測了卵形彈侵徹和貫穿混凝土靶板的侵徹深度和殘余速度,數(shù)值計(jì)算與實(shí)驗(yàn)數(shù)據(jù)吻合得較好。
[Abstract]:Concrete as a building material has been widely used in national defense and civil engineering, response and failure problems of concrete structures in explosive projectile impact or explosive under the action has important significance for the design of weapons and protective structure. The main work of this paper is to establish the dynamic constitutive model of concrete calculation of the new, and the response of the explosion load penetration problems and its application in the explosive concrete target in high velocity projectile impact condition, predicting the depth of penetration, projectile residual velocity, propagation and evolution of acceleration and the crack in the concrete target. This paper mainly includes the following aspects:
In the existing concrete constitutive model and some new experimental data, a new constitutive model to calculate the dynamic development of concrete. The model can reflect the basic characteristics of concrete materials such as pressure correlation, strain rate, strain softening, loading path dependence, porous and low confining pressures for concrete tensile damage damage. This paper introduces the main material, the tensile strain damage rule to describe the tensile cracking behavior of concrete material. The dynamic strength of concrete materials, based on the analysis of the existing concrete compressive and tensile dynamic material experimental data, based on two assumptions on the proposed new concrete dynamic enhancement factor (DIF) of the empirical formula two. A hypothesis of this model is: the inertial effect has influence only on the dynamic strength of concrete compression, has no effect on the dynamic tensile strength should be in the same; The dynamic compressive strength increment of concrete material is the same as that of dynamic tensile strength under variable rate condition. We will use the numerical calculation of single element model to verify the correctness of the constitutive model.
Numerical simulation of high speed ovoid projectile penetration into reinforced concrete targets. The ovoid projectile runs through 48MPa, 140MPa, 38MPa in concrete target of finite thickness, as well as the oval 39MPa projectiles of semi infinite concrete targets was simulated, and the numerical simulation of residual velocity and penetration depth (minus) and comparison acceleration results and experimental data were found in goodagreement. At the same time, the numerical simulation also reveals the concrete target through the evolution process of crack in the oval projectile, the diameter of the crater and the crater diameter and the experimental data obtained in numerical simulation are in good agreement.
The wadcutter numerical simulation with different impact velocity of reinforced concrete targets. By numerical simulation and experiment of concrete slab crack morphology photographs well. At the same time, the wadcutter impact concrete target is studied and analyzed the wadcutter impact velocity, flat projectile diameter and mass, thickness and diameter of concrete target in effect on the evolution of crack in the concrete target, and some useful conclusions are obtained.
The response of reinforced concrete explosion loads and failure to carry out numerical simulation. Simulation of explosives and explosives in a closed contact explosion explosion problem in space. Numerical simulation of crack morphology and experimental observation of concrete target are compared, which is in good agreement with the explosion problem. At the same time, contact of concrete was studied analysis of the impact of concrete targets, different diameter plate of different thickness on crack evolution.
The Hoek-Brown failure criterion into the cavity expansion theory, and the numerical calculation of penetration problems. Firstly Hoek-Brown failure criterion and elastic - brittle - ideal plastic stress-strain relationship into the spherical cavity expansion theory, used to describe the constitutive relationship and failure process of concrete materials, to make up for the past the simple hole defects of expansive concrete material theory. The constitutive model captures the basic mechanical behavior of concrete materials, such as pressure correlation, strain softening, can reflect the mechanical behavior of concrete materials. Through the numerical method to predict the ovoid projectile penetration and perforation penetration depth of concrete target and the residual velocity, numerical calculation agree well with experimental data.

【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TU528.01

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本文編號：1640258