【摘要】：激光沖擊強(qiáng)化作為一種前沿的表面處理技術(shù),具備“三高一快”(高壓、高能、超快、高應(yīng)變率)特點(diǎn),可以廣泛應(yīng)用在金屬和零部件的強(qiáng)化上。各國研究人員已經(jīng)對激光沖擊強(qiáng)化技術(shù)進(jìn)行了系統(tǒng)研究,但都是在航空鋁合金材料方面,而在航空工業(yè)有重要作用的高質(zhì)量合金鋼的科學(xué)研究則比較少。40Cr鋼在航空工業(yè)上常使用在高速和沖擊負(fù)荷小的工作環(huán)境中,而傳統(tǒng)的表面強(qiáng)化方法主要存在效率低、溫度高、工作環(huán)境差等缺點(diǎn)。針對上面提到的問題,本文以40Cr鋼為研究對象,采用ABAQUS有限元軟件系統(tǒng)研究了不同工藝參數(shù)(沖擊次數(shù)、光斑直徑、沖擊波加載時間、激光能量和壓力幅值上升時間)對激光沖擊強(qiáng)化的影響。對不同的搭接率布置方案激光沖擊強(qiáng)化進(jìn)行了分析。研究了正反表面同時沖擊和間隔沖擊在殘余應(yīng)力和表面變形的差異,并探討了正反表面間隔沖擊兩次,三種順序?qū)堄鄳?yīng)力和“殘余應(yīng)力洞”的影響。采用脈沖激光器對40Cr鋼方塊試樣進(jìn)行激光沖擊強(qiáng)化處理并與模擬結(jié)果進(jìn)行對比。分析“殘余應(yīng)力洞”產(chǎn)生原理、以及不同工藝參數(shù)對其影響,研究了兩種對“殘余應(yīng)力洞”抑制的方法。(1)通過ABAQUS有限元軟件構(gòu)建了三維分析模型,研究了不同工藝參數(shù)對沖擊強(qiáng)化在殘余應(yīng)力、應(yīng)變和表面變形等方面的影響規(guī)律并分析了對“殘余應(yīng)力洞”問題的影響。對40Cr鋼進(jìn)行了較為系統(tǒng)的激光沖擊強(qiáng)化數(shù)值模擬研究,分析了不同工藝參數(shù)對其強(qiáng)化效果的影響規(guī)律。以不同激光沖擊強(qiáng)化次數(shù)為例,激光沖擊次數(shù)為1次、2次和3次時,殘余壓應(yīng)力最大值分別為468.36 MPa、540.87 MPa和556.31MPa,壓應(yīng)力影響層深度也不斷增大。隨著沖擊強(qiáng)化次數(shù)增大在表面變形、等效塑性應(yīng)變方面也隨之增加。分析了不同參數(shù)對“殘余應(yīng)力洞”問題的影響,闡明了并不是沖擊次數(shù)越多、脈沖加載時間越長,能量越大對強(qiáng)化效果就越好。(2)研究了不同光斑搭接率布置方案下的激光沖擊強(qiáng)化效果,為后續(xù)大面積激光沖擊強(qiáng)化奠定了基礎(chǔ)。研究了正反表面同時沖擊和間隔沖擊在殘余應(yīng)力、表面變形和等效塑性應(yīng)變的差異。研究得出了隨光斑搭接率的增大,試樣表面變形和殘余應(yīng)力分布變得相對均勻的結(jié)論。當(dāng)光斑搭接率較小和較大時,表面變形數(shù)值會比較大。正反表面同時沖擊比間隔沖擊在正反表面應(yīng)力分布上有更好的一致性。(3)分析了正反表面間隔沖擊兩次,三種沖擊順序的優(yōu)劣。正反表面間隔沖擊兩次有三種沖擊順序,沖擊順序一:正反正反;沖擊順序二:正正反反;沖擊順序三:正反反正。采用沖擊順序一和沖擊順序二在正面的殘余壓應(yīng)力比反面的大,采用沖擊順序三,結(jié)果正好相反,沖擊順序二產(chǎn)生的“殘余應(yīng)力洞”現(xiàn)象最小。(4)對40Cr鋼進(jìn)行了不同能量的激光沖擊強(qiáng)化處理,通過分析不同能量下激光沖擊強(qiáng)化后試樣殘余應(yīng)力分布的試驗(yàn)結(jié)果與模擬結(jié)果的異同,從而驗(yàn)證了數(shù)值模擬結(jié)果的準(zhǔn)確性。研究了抑制“殘余應(yīng)力洞”問題的方法。針對不同能量的激光沖擊強(qiáng)化處理,通過X射線應(yīng)力測試儀對沖擊后試樣表面和深度方向的殘余應(yīng)力進(jìn)行了測量并與模擬數(shù)值對比。試驗(yàn)獲得表面壓應(yīng)力最大值為461 MPa,與模擬得到的壓應(yīng)力最大值447.5 MPa很相近。研究了通過二元光學(xué)衍射將圓形光斑改變?yōu)榉叫喂獍吆褪褂霉獍叽罱勇蔬M(jìn)行大面積激光沖擊可以有效地抑制“殘余應(yīng)力洞”問題。得出了激光沖擊最優(yōu)搭接率應(yīng)該在50%~75%之間選擇的結(jié)論。
[Abstract]:Laser shock strengthening, as a front surface treatment technology, has the characteristics of "three high and one fast" (high pressure, high energy, super fast, high strain rate), which can be widely used in the strengthening of metal and parts. The scientific research of high quality alloy steel which plays an important role in air industry, less.40Cr steel is often used in the working environment of high speed and low impact load in aeronautical industry, and the traditional method of surface hardening mainly has the disadvantages of low efficiency, high temperature and poor working environment. In view of the problems mentioned above, 40Cr steel is the research object in this paper. The influence of different process parameters (impact times, spot diameter, shock wave loading time, laser energy and pressure amplitude rising time) on laser shock intensification is studied by using the ABAQUS finite element software system. The laser impact intensification of different lap rate arrangement is analyzed. The simultaneous impact and interval impact on the positive and negative surfaces are studied. The difference between the residual stress and the surface deformation, and the influence of the positive and negative surface interval impact two times, the effect of the three sequence on the residual stress and the "residual stress hole". The pulse laser is used to strengthen the laser shock treatment of the 40Cr steel block specimen and compare it with the simulation results. The effect of process parameters on two kinds of "residual stress holes" was studied. (1) a three-dimensional analysis model was constructed by ABAQUS finite element software, and the influence of different process parameters on the impact strengthening on residual stress, strain and surface deformation was studied and the effect on the "residual stress hole" was analyzed. 40C A relatively systematic numerical simulation of laser impact strengthening was carried out in R steel, and the influence of different process parameters on its strengthening effect was analyzed. The maximum number of residual stresses was 468.36 MPa, 540.87 MPa and 556.31MPa, and the depth of the stress affected layer, when the number of laser impact strengthening times was 1 times, 2 times and 3 times, respectively. As the number of impact strengthening increases on the surface, the equivalent plastic strain also increases. The influence of different parameters on the "residual stress hole" is analyzed, and it is stated that the more the impact times, the longer the pulse loading time is, the better the energy is, the better the strengthening effect is. (2) research on the overlap ratio of different light spots. The effect of laser shock enhancement under the set scheme is the foundation for the subsequent large area laser shock strengthening. The difference of residual stress, surface deformation and equivalent plastic strain is studied at the simultaneous impact and interval impact on the positive and negative surfaces. The results show that the surface deformation and residual stress distribution of the specimen are relatively uniform with the increase of the overlap rate of the spot. When the lap rate is small and large, the surface deformation value will be larger. The positive and negative surface impact is better consistent with the distribution of the stress distribution on the positive and negative surface. (3) the positive and negative surface interval impact is two times, and the three kinds of impact sequence are good and bad. The positive and negative surface interval impact has three kinds of impact order, the impact is impacted. Sequence one: positive and negative positive and negative; impact sequence two: positive and negative reaction; impact order three: positive and negative inverse. The residual pressure stress in the frontal sequence and impact order two is larger than the reverse side, using the impact order three, the result is the opposite, the "residual stress hole" is the least. (4) different energy is carried out to 40Cr steel. By analyzing the laser shock intensification treatment, the accuracy of the numerical simulation results is verified by analyzing the difference between the experimental results and the simulated results of the residual stress distribution of the specimen after the laser shock intensification under different energy. The method to suppress the "residual stress hole" is studied. The X ray should be used for the laser shock strengthening treatment of different energy. The force tester measured the residual stress in the surface and depth direction of the specimen after impact and compared with the simulated numerical value. The maximum surface pressure stress of the test was 461 MPa, which was similar to the simulated maximum compressive stress of 447.5 MPa. The circular spot was changed to square spot by two element optical diffraction and the use of light spot lap. The problem of "residual stress hole" can be effectively suppressed by large area laser shock. The conclusion that the optimal lap rate of laser shock should be selected between 50%~75% can be obtained.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG665

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 劉波;羅開玉;吳劉軍;魯金忠;;激光沖擊強(qiáng)化對AM50鎂合金性能和結(jié)構(gòu)的影響[J];光學(xué)學(xué)報;2016年08期

2 曹宇鵬;徐影;馮愛新;花國然;周東呈;張津超;;激光沖擊強(qiáng)化7050鋁合金薄板表面殘余應(yīng)力形成機(jī)制的實(shí)驗(yàn)研究[J];中國激光;2016年07期

3 王長雨;羅開玉;魯金忠;;雙面激光噴丸條件下沖擊前進(jìn)方向?qū)M50鎂合金試樣殘余應(yīng)力場的影響[J];中國激光;2016年03期

4 王建明;趙莉莉;呂鶴婷;;噴丸殘余應(yīng)力對裂紋擴(kuò)展疲勞壽命的影響[J];哈爾濱工程大學(xué)學(xué)報;2016年04期

5 殷蘇民;汪偉力;錢紹祥;萬翔;張建明;;基于ABAQUS的2A11鋁焊接結(jié)構(gòu)激光沖擊處理數(shù)值模擬[J];金屬熱處理;2015年09期

6 聶祥樊;臧順來;何衛(wèi)鋒;趙潔;;激光沖擊“殘余應(yīng)力洞”的參數(shù)敏感性分析及其抑制方法[J];高電壓技術(shù);2014年07期

7 汪誠;賴志林;何衛(wèi)鋒;薛彥慶;周留成;;激光沖擊次數(shù)對1Cr11Ni2W2MoV不銹鋼高周疲勞性能的影響[J];中國激光;2014年01期

8 牛曉敏;夏亞濤;;有限元方法應(yīng)用研究現(xiàn)狀[J];科技致富向?qū)?2013年23期

9 鐘金杉;魯金忠;羅開玉;齊晗;王志龍;韓彬;劉娟;;激光沖擊對AISI304不銹鋼拉伸性能和摩擦磨損性能的影響[J];中國激光;2013年05期

10 程杰;袁祖強(qiáng);陸金桂;;基于Abaqus的大型風(fēng)力機(jī)葉片有限元分析[J];機(jī)械設(shè)計與制造;2012年05期

相關(guān)碩士學(xué)位論文 前4條

1 鮑士喜;耐熱馬氏體不銹鋼ЭП866激光沖擊強(qiáng)化組織與性能研究[D];江蘇大學(xué);2016年

2 吳鐵丹;AZ31鎂合金薄板激光沖擊溫成形實(shí)驗(yàn)及數(shù)值模擬[D];江蘇大學(xué);2016年

3 寧吉平;不銹鋼焊縫激光沖擊強(qiáng)化試驗(yàn)研究與有限元仿真分析[D];江蘇大學(xué);2010年

4 王云;結(jié)構(gòu)鋼大變形損傷本構(gòu)關(guān)系研究[D];西安建筑科技大學(xué);2005年

，

本文編號：2131397