【作者】 王宇飞；

【导师】 杨振国；

【作者基本信息】 复旦大学 ， 材料物理与化学， 2008， 博士

【摘要】 本文分两部分。第一部分主要讨论了耐磨复合管的制备、表征及有限元分析,在这一部分中,采用自蔓延高温合成和离心铸造相结合的工艺,制备了高耐磨陶瓷内衬复合管,对其反应原料和陶瓷内衬层制品的物相组成、物理性能等方面做了表征,并采用有限元方法对其制备过程中的管材残余应力进行了模拟分析;在此基础上,通过反应浸渍拼混树脂制备了三元复合管,对服役工况下不同组元材料所引起的界面应力进行了数值模拟。此外,设计并制造了冲蚀磨损试验机,对陶瓷内衬管和三元复合管的耐冲蚀性能进行了测试和评估。第二部分侧重于材料冲蚀磨损行为的数值模拟分析,主要讨论了冲蚀磨损的影响因素和韧性、脆性材料冲蚀失效的主要机制,提出了一个全新的通用有限元冲蚀模型,分别以钛合金和陶瓷材料为例进行了仿真模拟,总结了数值模拟技术在材料磨损失效领域的应用,并且,首次将无网格算法与有限元法相耦合的方法应用于磨损失效领域,建立了高速冲蚀磨损的耦合模型,改善了大变形带来网格畸变的情况,并使用该模型对工程材料及带有有机涂层的材料的沖蚀行为进行了讨论。本文具体研究内容及结果如下:1.高耐磨陶瓷内衬复合管的制备采用自蔓延高温合成与离心铸造相结合的工艺,研制了夹具式SHS-离心机,成功地在钢管内壁烧结出冶金结合的陶瓷内衬层,并对其反应原料及陶瓷制品采用DSC、XRD、EDS、SEM和TEM等方法进行了表征分析,表明新研制的陶瓷内衬复合管具有优异的耐磨耐蚀性能。2.陶瓷内衬复合管的残余应力模拟分析模拟分析了陶瓷内衬复合管在冷却凝固过程中的温度分布和变化,从而为工艺参数的选择和管道界面结构分析提供了基础。利用ANSYS软件的瞬态热分析功能和热-结构耦合功能,数值上模拟了复合管的温度场分布及残余热应力,分析了SHS反应层厚度对陶瓷内衬复合管性能的影响。数值分析结果表明,合理调整SHS反应层的厚度,可使界面残余热应力变小,从而提高陶瓷内衬复合管的安全可靠性。3.三元复合管的制备及组元材料的选择在陶瓷内衬复合管的基础上开发了内壁具有树脂层的三元复合管。该管道具有一定的耐磨性以及很高的防腐蚀效果,可用于腐蚀和磨损交互作用下的复杂工况。采用有限元法模拟了其在服役工况下受均匀内压时的应力分布情况,并研究了不同弹性模量和泊松比的陶瓷材料对三元复合管界面应力的影响,合理调整中间层陶瓷材料的弹性模量和泊松比,会减少界面处的环向应力,从而提高三元复合管的安全可靠性。4.层状复合管的冲蚀磨损试验针对管道服役工况下一种常见的冲蚀磨损失效形式,设计并制造了冲蚀试验机,并在此试验机上对陶瓷内衬管及三元复合管进行了冲蚀试验。结果表明:衬里层刚玉材料和拼混树脂的冲蚀行为均表现出典型的脆性冲蚀行为,在冲蚀角为90°左右受损最严重;经过改性纳米粒子的填充后,拼混树脂表现出优良的耐冲蚀磨损性能。5.冲蚀磨损的影响因素和机理研究从影响冲蚀磨损行为的因素入手,对材料的冲蚀磨损规律进行了深入研究。着重讨论了冲蚀角、冲蚀物速度、冲蚀物颗粒尺寸对冲蚀行为的影响,并从冲蚀磨损的韧性模式和脆性模式角度深入探讨了材料的摩擦磨损机理。同时对数值模拟方法在材料磨损领域的趋势进行了技术展望。6.冲蚀磨损的有限元模型建立了冲蚀磨损的显式动力学模型,分别使用不同的材料本构方程讨论了韧性材料和脆性材料在冲蚀磨损作用下的行为。与试验研究相似,采用有限元模型对冲蚀速度、冲蚀角、冲蚀物尺寸等因素对冲蚀率的影响分别给出了模拟结果。并通过计算得出了冲蚀过程中的能量转化情况与材料表面层的残余应力,有限元模拟的结果验证了已有的冲蚀机理。7.冲蚀磨损的耦合计算模型采用光滑质点流体动力学和有限单元相耦合的数值模型,解决了高速冲击带来的有限单元网格扭曲问题,并模拟分析了韧性材料,以及带有有机涂层的金属的高速冲蚀磨损行为,讨论了垂直冲击和斜角冲击时的能量转化和界面剪切应力情况,同时给出了在两种情况下涂层的分层机理。这对于高速冲蚀磨损机理的研究以及涂层分层脱落机理的研究具有一定的指导意义。更多还原

【Abstract】 The dissertation could be divided into two sections. The first section is mainly about the preparation, characterization and finite element （FE） analysis of the wear-resistant laminated composite pipe. The centrifugal-SHS process to prepare ceramic-lined composite pipe was introduced. The phase compositions and physical properties for the raw materials powders and the products have been characterized. The FE method has been adapted to simulate the residual thermal stresses in composite pipes. The ternary composite pipes were prepared by reactive impregnating blended resin onto the internal surface of ceramic-lined pipes. The interfacial stresses of the ternary composite pipe in service have been investigated through FE analysis. Furthermore, the erosion testing machine has been designed to test the erosion performance of two composite pipes. The second section of the dissertation is about the mechanism of the erosive wear and the erosion models. The impact factors of erosive wear on the materials and products have been discussed in details. The erosion mechanisms of ductile materials and brittle materials have been emphatically analyzed. And the application prospects for numerical simulation analysis techniques in the field of material wear were given as well. A brand new universal FE model of erosive wear was built. Utilizing the FE model, two examples of ductile materials and brittle materials were employed to simulate the effect of the impact angle, impact velocity and particles penetration on the targets. Moreover, a coupled model of erosive wear with meshfree simulation technique and FE method was established, which was the first time to use meshfree simulation technique in studying a wear process. The detailed research contents and results are summarized as follows:1. The preparation of the wear-resistant ceramic-lined composite pipeThe jig-type SHS-centrifugal machine has been designed using centrifugal-SHS process, with which the metallurgical bonding ceramic-lined has been successfully sintered into the internal surface of the steel pipe. The powders of raw materials and the products of ceramics-lined layer have been systemically characterized by DSC, XRD, EDS, SEM and TEM. The results display that the ceramic-lined pipe has outstanding erosion resistance and good thermal fatigue resistance and high surface hardness. It could be widely used in many fields such as electricity, petrochemical industry, metallurgy, chemical industries, etc.2. FE analysis of residual thermal stress in ceramic-lined composite pipeThe temperature distribution and transformation during the cooling process of the ceramic-lined composite pipe preparation were emphatically analyzed with FE method. With the function of transient thermal analysis and thermal-structure coupling of ANSYS, the residual thermal stress of the composite pipe was numerically simulated. The effect of the thickness of SHS-layer on the performance of the ceramic-lined composite pipe was investigated as well. The results of numerical analysis indicate that reasonable adjustment of the thickness of SHS-layer could reduce the interfacial stress between any two layers so that the service life, safety and reliability of the ceramic-lined composite pipe would be improved.3. The preparation of the ternary composite pipe and the effect of different component materials on pipeA kind of anti-corrosion ternary composite pipe was developed by reactive impregnating blended resin onto the internal surface of the ceramic-lined pipe. The ternary composite pipe could be used in the working conduction with the interaction of corrosion and wear. Utilized FE method, the characteristic for the interfaces of the composite pipe was numerically modeled and the effect of variation of their physical parameter on the mechanical property of the composite piping was analyzed as well. The numerical analysis results show that the reasonable adjustment of Young’s modulus and Poisson’s ratio of ceramic intermediate layer formed in the ternary composite pipe could reduce the interfacial stress between layers so that the service life and safety reliability of the pipe would be enhanced.4. The erosion test for the laminated composite pipeFor a common failure mode of erosive wear under pipe service conditions, according to the relevant standards, the erosion testing machine has been designed and manufactured. The erosion performances for the internal layer materials of the laminated composite pipe, Al₂O₃ ceramics of ceramic-lined pipe and blended resin sample of the ternary pipe, were examined on the erosion testing machine. The results indicate that the two linings show typical brittle erosive behavior, which has most serious damage at 90°impact angle. The blended resin which filled with modified nano-particles Al₂O₃ demonstrated excellent erosive wear resistance properties5. The impact factors of erosive wear and the erosion mechanism study.The materials erosive behavior was further studied from the impact factors of erosion. The effects of impact angle, erodent velocity and erodent particle size on weight loss of target materials were focused. The erosion failure mechanisms were particularly distinguished from ductile mode to brittle mode. At the same time, the application prospects for numerical simulation in the field of material wear failure were explained.6. FE model of erosive wear on ductile and brittle materialsA brand new universal FE model of erosive wear was established. The Johnson-Cook and Johnson-Holmquist materials model and the corresponding equation of state used in the FE model were described in more details. Utilizing the FE model, two examples of ductile materials and brittle materials were employed to simulate the effect of the impact angle, erodent velocity and particle size as well as particle penetration on the targets. The energy transfer and surface residual were calculated as well. It is shown that the predicted results are in agreement with published results obtained experimentally and from analytical erosion models. The present study could be useful and efficient in studying erosive wear.7. Coupled FE and meshfree model for erosive wearA coupled finite element and meshfree model was established for the simulation and prediction of erosive wear. The error due to mesh distortion and tangling at impacted area in the FE analysis could be avoided utilizing the meshfree technique. The computer simulations of high velocity erosive wear on a ductile target Ti-6Al-4V against steel particles’ impacting and on an aluminum substrate with organic coating have been performed. The fundamental mechanisms of erosion by solid particle impact and the coating debonding behavior were investigated through the coupled numerical model. The coupled model has instructive significance for researching the mechanisms of high velocity erosive wear and the coating debonding mechanisms.更多还原