【摘要】：基于節(jié)能與環(huán)保的需求,近年來結(jié)構(gòu)輕量化在車輛設(shè)計領(lǐng)域受到廣泛關(guān)注。在車身應(yīng)用方面,使用高性能輕質(zhì)材料替代傳統(tǒng)鋼材(如CFRP)是實現(xiàn)輕量化最為有效的方法之一。短期時間內(nèi),輕質(zhì)材料難以完全替代傳統(tǒng)車身材料,異質(zhì)材料在車身結(jié)構(gòu)中的共同應(yīng)用則會帶來一系列連接問題。與傳統(tǒng)連接方式相比,膠接技術(shù)質(zhì)量輕、應(yīng)力分布均勻、密封性好、抗疲勞強,在異質(zhì)材料連接方面具有較大優(yōu)勢。相對于傳統(tǒng)連接方式,膠接接頭服役性能研究較為有限,因此制約了其在汽車制造領(lǐng)域的應(yīng)用。車輛在服役過程中,異質(zhì)材料連接部位由于長期受到地面動態(tài)載荷的激勵而可能發(fā)生破壞,而對關(guān)鍵部位疲勞壽命的準(zhǔn)確預(yù)測能夠保證車身達(dá)到輕量化的同時滿足車身疲勞性能的要求。目前對于金屬膠接接頭疲勞的試驗研究與數(shù)值仿真都較為完善,然而仍然缺乏對復(fù)合材料-金屬膠接接頭疲勞服役性能方面的研究。本文以復(fù)合材料基礎(chǔ)力學(xué)性能與鋼-CFRP膠接接頭在恒幅載荷下疲勞損傷特性為研究對象,主要開展了以下幾個方面工作：(1)使用試驗方法與理論模型分別對某型復(fù)合材料與接頭基底CFRP材料宏觀力學(xué)性能進(jìn)行了研究。通過制造相應(yīng)夾具,對某型復(fù)合材料標(biāo)準(zhǔn)試件進(jìn)行了準(zhǔn)靜態(tài)基礎(chǔ)力學(xué)性能測試,得到了該復(fù)合材料準(zhǔn)靜態(tài)拉伸、剪切以及壓縮力學(xué)性能參數(shù)；使用復(fù)合材料宏觀力學(xué)模型與Halpin/Tsai模型分別獲取了接頭基底CFRP材料基礎(chǔ)力學(xué)性能參數(shù),同時基于兩種不同材料參數(shù)值在ABAQUS(?) CAE中建立了CFRP準(zhǔn)靜態(tài)拉伸有限元模型,通過與試件拉伸試驗結(jié)果對比選取較為接近的仿真模型。(2)使用試驗方法對鋼-CFRP膠接接頭在恒幅載荷下疲勞損傷特性進(jìn)行了研究�；谌珘勖跍y試方法獲取了鋼-CFRP膠接接頭在特定恒幅載荷下的疲勞壽命,使用背面應(yīng)變法記錄了接頭膠層裂紋擴展過程中背部應(yīng)變變化情況,同時以不同加載周期接頭的剩余強度與固有頻率變化值對膠層疲勞損傷特性進(jìn)行了研究。通過分析接頭在不同加載周期剛度與強度的退化情況研究了接頭疲勞損傷對其靜態(tài)與動態(tài)性能的影響。
[Abstract]:Based on the demand of energy saving and environmental protection, structural lightweight has been paid more and more attention in the field of vehicle design in recent years. In body application, the use of high performance lightweight materials to replace traditional steel (such as CFRP) is one of the most effective methods to achieve lightweight. In the short term, lightweight materials can not replace traditional body materials completely, and the joint application of heterogeneous materials in body structure will lead to a series of connection problems. Compared with the traditional bonding technology, the bonding technology has the advantages of light weight, uniform stress distribution, good sealing and fatigue resistance, and has great advantages in the connection of heterogeneous materials. Compared with the traditional connection mode, the service performance of adhesive joint is limited, so its application in automobile manufacturing field is restricted. During the service of the vehicle, the connection part of heterogeneous material may be destroyed because of the excitation of dynamic load on the ground for a long time. The accurate prediction of the fatigue life of the key parts can ensure the lightweight of the body and meet the requirements of the fatigue performance of the body. At present, the fatigue test and numerical simulation of metal bonded joints are relatively perfect, but there is still no research on fatigue service performance of composite metal bonded joints. In this paper, the mechanical properties of composite foundation and fatigue damage characteristics of steel-CFRP joints under constant amplitude loading are studied. The main works are as follows: (1) the macroscopic mechanical properties of a composite material and a joint substrate CFRP material are studied by means of test method and theoretical model. The quasi static basic mechanical properties of a kind of composite material standard specimen were tested by making the corresponding fixture, and the mechanical properties parameters of quasi-static tensile, shear and compression of the composite were obtained. The mechanical properties of the CFRP material base on the joint substrate were obtained by using the composite macro mechanical model and the Halpin/Tsai model, respectively, and based on the values of two different material parameters, the mechanical properties of the CFRP material were obtained in the ABAQUS (?) The quasi-static tensile finite element model of CFRP is established in CAE, and the simulation model is chosen by comparing with the results of tensile test. (2) the fatigue damage characteristics of steel-CFRP adhesive joints under constant amplitude loading are studied by means of test method. Based on the whole life fatigue test method, the fatigue life of steel CFRP adhesive joint under constant amplitude load is obtained. The back strain method is used to record the back strain change during crack propagation of the adhesive layer of the joint. At the same time, the fatigue damage characteristics of the adhesive layer were studied with the change of residual strength and natural frequency of the joints with different loading periods. The effects of fatigue damage on the static and dynamic properties of joints were studied by analyzing the degradation of stiffness and strength of joints under different loading periods.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：U465

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本文編號：2312868