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广州有道计算机科技有限公司有限元分析FEA有限元法（FEA，Finite Element Analysis）的基本概念是用较简单的问题代替复杂问题后再求解。
它将求解域看成是由许多称为有限元的小的互连子域组成，对每一单元假定一个合适的(较简单的）近似解，然后推导求解这个域总的满足条件(如结构的平衡条件），从而得到问题的解。
这个解不是准确解，而是近似解，因为实际问题被较简单的问题所代替。
由于大多数实际问题难以得到准确解，而有限元不仅计算精度高，而且能适应各种复杂形状，因而成为行之有效的工程分析手段。
有限元分析（FEA，Finite Element Analysis）利用数学近似的方法对真实物理系统（几何和载荷工况）进行模拟。
还利用简单而又相互作用的元素，即单元，就可以用有限数量的未知量去逼近无限未知量的真实系统。
大型通用有限元商业软件：如ANSYS可以分析多学科的问题，例如：机械、电磁、热力学等；电机有限元分析软件NASTRAN等。
还有三维结构设计方面的UG、CATIA、Proe等都是比较强大的。
国产有限元软件：FEPG、SciFEA、,JiFEX、KMAS等有限元法：把求解区域看作由许多小的在节点处相互连接的单元（子域）所构成，其模型给出基本方程的分片（子域）近似解，由于单元（子域）可以被分割成各种形状和大小不同的尺寸，所以它能很好地适应复杂的几何形状、复杂的材料特性和复杂的边界条件。
有限元方法的基础是变分原理和加权余量法，其基本求解思想是把计算域划分为有限个互不重叠的单元，在每个单元内，选择一些合适的节点作为求解函数的插值点，将微分方程中的变量改写成由各变量或其导数的节点值与所选用的插值函数组成的线性表达式，借助于变分原理或加权余量法，将微分方程离散求解。
采用不同的权函数和插值函数形式，便构成不同的有限元方法。
有限元法的收敛性是指：当网格逐渐加密时，有限元解答的序列收敛到精确解；或者当单元尺寸固定时，每个单元的自由度数越多，有限元的解答就越趋近于精确解。
有限元分析ANSYS简单入门教程有限元分析（finite element analysis，简称FEA）是一种数值分析方法，广泛应用于工程设计、材料科学、地质工程、生物医学等领域。
ANSYS是一款领先的有限元分析软件，可以模拟各种复杂的结构和现象。
本文将介绍ANSYS的简单入门教程。
1.安装和启动ANSYS2. 创建新项目(Project)点击“New Project”，然后输入项目名称，选择目录和工作空间，并点击“OK”。
这样就创建了一个新的项目。
3. 建立几何模型（Geometry）在工作空间内，点击左上方的“Geometry”图标，然后选择“3D”或者“2D”，根据你的需要。
在几何模型界面中，可以使用不同的工具进行绘图，如“Line”、“Rectangle”等。
4. 定义材料（Material）在几何模型界面中，点击左下方的“Engineering Data”图标，然后选择“Add Material”。
在材料库中选择合适的材料，并输入必要的参数，如弹性模量、泊松比等。
5. 设置边界条件（Boundary Conditions）在几何模型界面中，点击左上方的“Analysis”图标，然后选择“New Analysis”并选择适合的类型。
然后，在右侧的“Boundary Conditions”面板中，设置边界条件，如约束和加载。
6. 网格划分（Meshing）在几何模型界面中，点击左上方的“Mesh”图标，然后选择“Add Mesh”来进行网格划分。
可以选择不同的网格类型和规模，并进行调整和优化。
7. 定义求解器（Solver）在工作空间内，点击左下方的“Physics”图标，然后选择“Add Physics”。
选择适合的求解器类型，并输入必要的参数。
8. 运行求解器（Run Solver）在工作空间内，点击左侧的“Solve”图标。
ANSYS会对模型进行求解，并会在界面上显示计算过程和结果。
有限元分析方法有限元分析（Finite Element Analysis, FEA）是一种数值分析方法，用于解决物理问题的近似解。
它基于将有限元区域（即解释对象）分解成许多简单的几何形状（有限元）并对其进行数值计算的原理。
本文将深入探讨有限元分析的原理、应用和优点。
有限元分析的原理基于弹性力学理论和数值计算方法。
它通过将解释对象分解为有限个简单的几何区域（有限元）和节点，通过节点之间的连接来建立模型。
这些节点周围的解释对象区域称为“单元”，并且通过使用单元的形状函数近似解释对象的形状。
每个单元都有一个与之相连的节点，通过对每个单元的受力进行计算，可以得到整个解释对象的受力分布。
然后，利用一系列运算和迭代，可以计算出解释对象的位移、应力和变形等相关参数。
有限元分析的应用范围广泛，从结构力学、热传导、电磁场分析到流体力学等各个领域。
在结构力学中，它被用于分析各种结构的静力学、动力学和疲劳等性能。
在热传导领域，它可以用于研究物体内部的温度分布和传热性能。
在电磁场分析中，它可用于计算复杂电磁场下的电场、磁场和电磁场耦合问题。
在流体力学中，有限元方法可以解决各种流体流动、热传递和质量转移问题。
有限元分析的优点之一是可以处理各种复杂边界条件和非线性材料特性。
它可以考虑到不同材料的非线性本质，例如弹塑性和接触等问题。
另外，有限元方法还可以适应任意形状和尺寸的几何模型，因此非常适用于复杂工程问题的建模与分析。
有限元分析的使用需要一定的专业知识和经验。
首先，需要将解释对象抽象成几何模型，并进行细分和离散化。
其次，需要选择适当的几何元素和材料模型，以及合适的边界条件和加载方式。
然后，需要定义求解器和数值方法，并使用计算机程序对模型进行计算。
最后，需要对结果进行后处理和验证，以确保其准确性和可靠性。
总的来说，有限元分析是一种强大的工程分析工具，在解决各种物理问题方面有广泛的应用。
它通过将复杂的问题简化为简单的有限元模型，通过数值计算的方法获得近似解。
Finite Element Analysis (FEA) Finite Element Analysis (FEA) is a powerful tool used in engineering to simulate and analyze the behavior of structures and components under various conditions. It is widely used in industries such as aerospace, automotive, civil engineering, and many others to ensure the safety and performance of designsbefore they are physically constructed. FEA involves breaking down a complex system into smaller, more manageable elements, and then using mathematical equations to predict how these elements will behave under different loads and boundary conditions. One of the key benefits of FEA is its ability to optimize designs by identifying areas of high stress or deformation. This allows engineers to make informed decisions about material selection, geometry, and other design parameters to improve the overall performance and longevity of a structure. By simulating the behavior of a design under different scenarios, FEA can also help engineers identify potential failure points and make necessary design changes to prevent catastrophic failures in the real world. FEA also plays a crucial role in the development of new products and technologies. By using virtual simulations, engineers can test and refine their designs without the need for costly and time-consuming physical prototypes. This not only speeds up the design process but also reduces the overall development costs. Additionally, FEA allows for theexploration of a wide range of design alternatives, leading to more innovative and efficient solutions. In the context of sustainability and environmental impact, FEA can help engineers optimize designs to minimize material usage and energy consumption. By simulating the performance of different design options, engineers can make more informed decisions that lead to more sustainable products and structures. This is particularly important in industries such as construction and transportation, where the environmental impact of materials and designs can be significant. From a safety perspective, FEA is instrumental in ensuring that structures and components meet regulatory standards and can withstand extreme conditions. Whether it's designing a new aircraft wing or a bridge, FEA allows engineers to test for a wide range of scenarios, including earthquakes, high winds, and impact loads. This level of analysis and testing is critical in ensuring the safety and reliability of structures that millions of people rely on every day.In conclusion, Finite Element Analysis (FEA) is a vital tool in modern engineering that enables engineers to simulate, analyze, and optimize designs in a virtual environment. Its impact is far-reaching, from improving the performance and longevity of structures to accelerating the development of new products and technologies. FEA also plays a crucial role in promoting sustainability and ensuring the safety and reliability of structures in various industries. As technology continues to advance, FEA will undoubtedly remain an essential tool for engineers seeking to push the boundaries of innovation and design.。
有限元分析及应用介绍有限元分析，简称FEA（Finite Element Analysis），是一种数值计算方法，用于预测结构的力学行为。
它可以将结构离散为有限个小单元，在每个小单元内进行力学计算，并通过求解得到整个结构的应力和位移分布。
有限元分析常用于工程领域中，如结构分析、热传导分析、流体流动分析等。
原理有限元分析的基本原理可以概括为以下几个步骤：1.离散化：将结构或物体离散为有限个小单元。
常见的小单元形状有三角形、四边形等，在三维问题中可以使用四面体、六面体等。
2.建立数学模型：在每个小单元内，根据结构的物理特性和力学行为建立数学模型。
模型中包括了材料的弹性模量、泊松比等参数，以及加载条件、约束条件等。
3.组装和求解：将所有小单元的数学模型组装成一个整体的数学模型，然后利用求解算法进行求解。
常见的求解算法有直接法、迭代法等。
4.后处理：得到结构的应力和位移分布后，可以进行各种后处理操作，如绘制位移云图、应力云图等，以帮助工程师分析结构的强度和刚度性能。
应用有限元分析在工程领域有着广泛的应用。
下面介绍几个常见的应用案例：结构分析有限元分析可以用于结构分析，以评估结构的刚度和强度。
在设计建筑、桥梁、航空器等工程项目时，工程师可以使用有限元分析来模拟结构的力学行为，预测结构在不同加载条件下的变形和应力分布，以优化结构设计。
热传导分析有限元分析也可以用于热传导分析，在工程项目中评估热传导或热辐射过程。
例如，在电子设备的散热设计中，可以使用有限元分析来预测电子元件的温度分布，优化散热设计，确保电子元件的正常工作。
流体流动分析在流体力学研究中，有限元分析可以用于模拟流体的运动和流动行为。
例如，在船舶设计中，可以使用有限元分析来模拟船体受到波浪作用时的变形和应力分布，验证船体的可靠性和安全性。
优缺点有限元分析具有以下优点：•可以模拟复杂结构和物理现象，提供准确的结果。
•可以优化结构设计，减少设计成本和时间。
几乎所有的有限元分析的软件介绍——让你对CAE软件更了解有限元分析（Finite Element Analysis，FEA）是一种数值计算方法，用于求解结构、固体力学、热传导和流体力学等领域中的工程问题。
它通过离散化技术将复杂的连续体问题转化为一个有限数量的单元问题，再通过求解这些单元的代数方程组得到整个问题的近似解。
在工程领域，有限元分析常常被用来进行结构强度、振动、疲劳和优化分析等。
下面将介绍几个常见的有限元分析软件，包括ANSYS、ABAQUS、LS-DYNA和SolidWorks Simulation。
1.ANSYSANSYS是一款全面的有限元分析软件，包含了结构分析、流体动力学、电磁场分析和耦合多场分析等功能。
它具有强大的前后处理功能和丰富的材料模型库，可以模拟各种复杂的物理现象。
ANSYS还提供了多种优化算法，用于进行结构和材料参数的优化设计。
它广泛应用于航空航天、汽车、能源和电子等领域。
2.ABAQUSABAQUS是一款广泛应用于工程和科学领域的有限元分析软件，主要用于求解复杂的结构、流体和热力学问题。
它具有强大的建模和求解能力，支持线性和非线性分析。
ABAQUS还提供了各种完整的元件库和材料模型，同时支持多学科的耦合分析。
它适用于多种工程和科学领域，如航空航天、汽车、生物医学和材料科学等。
3.LS-DYNALS-DYNA是一款专注于动力学和非线性问题的有限元分析软件，用于模拟高速碰撞、爆炸和弹道问题等。
它具有优秀的显式求解器和平行计算能力，能够处理大型和复杂的模型。
LS-DYNA还提供了丰富的材料模型和接触算法，支持多物理场耦合。
它适用于汽车、航空航天、国防和地震等领域。
4. SolidWorks SimulationSolidWorks Simulation是一款基于SolidWorks CAD软件的有限元分析工具，用于进行结构和流体力学分析。
它提供了友好的用户界面和强大的建模和分析功能，能够快速进行设计验证和性能优化。
有限元分析总结引言有限元分析（Finite Element Analysis，简称FEA）是一种广泛应用于工程、物理学等领域的计算方法，用于模拟和分析复杂结构的行为。
通过将复杂结构离散为许多小的有限元件，然后利用数值方法求解这些元件的行为，从而得到整个结构的行为情况。
本文将对有限元分析的原理、应用和优缺点进行总结。
有限元分析原理有限元分析的核心思想是将连续结构离散化，并假设每个小元素的行为是线性的。
然后，通过构建结构的刚度矩阵和荷载向量的方程组，利用数值计算方法求解节点的位移和应力分布。
具体的步骤如下：1.确定要分析的结构的几何形状，将其划分为有限数目的小单元，例如三角形或四边形元素。
2.在每个小单元内，选取适当的插值函数来估计位移和应力分布。
3.根据连续性条件，建立整个结构的刚度矩阵。
刚度矩阵的元素代表了各节点的相互作用关系。
4.构建荷载向量，其中包括外界载荷和边界条件。
5.求解线性方程组，得到结构的节点位移和应力分布。
6.进一步分析节点位移和应力数据，得到结构的各种性能指标。
有限元分析应用有限元分析在工程领域有着广泛的应用，例如：•结构强度分析：通过有限元分析可以评估结构在受载情况下的应力和变形情况，以及可能的破坏模式。
•热传导分析：有限元分析可以模拟热传导过程，预测物体内部的温度分布，以及热传导对结构性能的影响。
•流体力学分析：有限元分析可以描述流体的流动行为，例如流体中的速度、压力分布等。
•多物理场耦合分析：如结构与热传导、流体力学等多个物理领域的耦合问题，可以利用有限元分析进行综合分析。
有限元分析优缺点有限元分析作为一种数值计算方法，具有一些明显的优点和缺点：优点：•可以模拟和分析复杂结构的行为，如非线性和非均匀材料，不规则几何形状等。
•可以提供详细的节点位移和应力分布数据，对结构性能进行深入分析。
•可以快速进行多次迭代计算，探索不同设计参数对结构性能的影响。
•可以进行实时动态仿真和优化，为工程设计提供重要的支持。
有限元分析在轮胎结构设计中的应用有限元分析（Finite Element Analysis，简称FEA）是一种应用数学方法和计算方法解决物理领域中的工程和科学问题的技术。
在轮胎结构设计中，有限元分析可以发挥重要作用。
本文将探讨有限元分析在轮胎结构设计中的应用。
首先，有限元分析可以用于轮胎的结构分析。
在轮胎的结构设计过程中，了解和评估轮胎的结构性能是非常重要的。
有限元分析可以帮助工程师对轮胎的不同部分进行细节分析，如轮胎的胎面、胎肩、胎侧等等。
通过有限元分析，可以模拟轮胎在不同道路条件下的受力情况，研究轮胎的应力、变形和疲劳等特性。
这有助于工程师了解轮胎的强度和刚度，为轮胎设计提供依据。
其次，有限元分析可以用于轮胎的耐久性分析。
耐久性是轮胎结构设计的一个重要指标。
有限元分析可以帮助工程师模拟轮胎在实际使用条件下的循环荷载作用下的疲劳性能。
通过有限元分析，可以评估轮胎的寿命和耐久性，预测轮胎在不同使用条件下的损坏情况。
这有助于工程师确定合适的轮胎材料和结构设计，提高轮胎的寿命和可靠性。
另外，有限元分析还可以用于轮胎的车辆动力学分析。
轮胎在车辆行驶过程中，承受着来自地面的力和转矩，对行驶稳定性和操控性起着关键作用。
有限元分析可以帮助工程师模拟轮胎和地面之间的接触力，研究轮胎的摩擦特性和动力学行为。
通过有限元分析，可以评估轮胎在转弯、制动和加速等情况下的性能，优化轮胎的设计参数，提高车辆的操控性和行驶稳定性。
此外，有限元分析还可以用于轮胎的优化设计。
通过有限元分析，工程师可以设计和评估不同的结构方案，优化轮胎的性能。
例如，可以通过有限元分析评估轮胎胎面花纹的设计对轮胎的排水性能和抓地力的影响，优化胎面花纹的形状和纹样。
此外，还可以通过有限元分析优化轮胎的结构参数，如胎压、胎宽和胎壁高度等，以获得更好的性能和经济性。
总而言之，有限元分析在轮胎结构设计中的应用十分广泛。
通过有限元分析，可以模拟轮胎的结构和性能，研究轮胎的强度、疲劳性能和动力学行为，优化轮胎的设计参数，提高轮胎的性能和可靠性。
Finite Element Analysis (FEA) Finite Element Analysis (FEA) is a powerful tool used in engineering to simulate and analyze the behavior of structures and components under various conditions. It is a numerical method that divides a complex system into smaller, simpler elements, allowing engineers to accurately predict how the system will respond to different loads and constraints. FEA has revolutionized the way engineers design and optimize structures, leading to safer, more efficient, and cost-effective solutions. One of the key benefits of FEA is its ability to simulate real-world conditions and scenarios that would be difficult or impossible to replicate in a physical test. By inputting material properties, boundary conditions, and loads into the FEA software, engineers can quickly analyze the stress, strain, and deformation of a structure, helping them identify potential failure points and optimize the design before manufacturing. This virtual testing not only saves time and resources but also reduces the risk of costly errors and failures in the field. FEA is widely used in various industries, including aerospace, automotive, civil engineering, and biomechanics, to name a few. In aerospace, FEA is used to analyze the structural integrity of aircraft components, ensuring they can withstand the extreme forces and vibrations experienced during flight. In automotive engineering, FEA helps optimize the design of vehicle components to improve performance, safety, and fuel efficiency. In civil engineering, FEA is used to analyze the stability of bridges, buildings, and other structures under different loading conditions. Despite its numerous advantages, FEA has its limitations and challenges. One of the main challenges is the accuracy of the results, which heavily depend on the input parameters, such as material properties and boundary conditions. Small errors in these parameters can lead to significant discrepancies in the simulation results, highlighting the importance of proper validation and verification of the FEA model. Additionally, FEA requires specialized training and expertise to use effectively, as well as powerful computing resources to handle the complex calculations involved in the analysis. Another important consideration when using FEA is the validation of the results through experimental testing. While FEA can provide valuable insights into the behavior of a structure, it is essential to validate the simulation resultsthrough physical testing to ensure the accuracy and reliability of the model. This iterative process of simulation and testing helps engineers refine their FEA models and improve the overall design of the structure. In conclusion, Finite Element Analysis is a valuable tool that has revolutionized the field of engineering by enabling engineers to simulate and analyze complex structures with accuracy and efficiency. While FEA offers numerous benefits, such as virtual testing, optimization, and cost savings, it also comes with challenges, such as accuracy, expertise, and validation. By understanding these limitations and best practices, engineers can harness the power of FEA to design safer, more reliable, and innovative structures that meet the demands of our modern world.。
有限元分析报告1. 引言有限元分析（Finite Element Analysis）是一种数值计算方法，用于求解工程和科学领域中的复杂问题。
它利用离散化技术将连续问题转化为离散问题，并应用数值算法进行求解。
本报告将主要介绍有限元分析的基本原理、应用和分析结果。
2. 有限元分析基本原理有限元分析的基本原理是将求解区域划分为互不重叠的有限个小单元，并将问题转化为在每个小单元内求解。
这些小单元通常为简单的几何形状，如三角形或四边形。
然后，在每个小单元内应用适当的数学模型和力学方程，得到相应的微分方程。
接着，通过对每个小单元的微分方程进行积分，并利用边界条件和连续性条件，得到整个求解区域的离散形式。
最后，通过求解离散形式的方程组，得到整个系统的解。
3. 有限元分析应用有限元分析在工程领域有着广泛的应用。
以下是几个典型的应用案例：3.1 结构分析有限元分析在结构分析中的应用非常广泛，可以用于确定结构的强度和刚度，评估结构的安全性，并进行结构优化设计。
通过对结构施加正确的边界条件和加载条件，可以得到结构的应力、应变和变形等重要信息。
3.2 流体力学分析有限元分析在流体力学分析中的应用可以用于模拟流体的流动和传热过程，例如气体和液体的流动、传热设备的设计优化等。
通过分析流体系统的流速、压力和温度等参数，可以对流体系统的性能和行为进行合理评估。
3.3 热力学分析有限元分析在热力学分析中的应用可以用于分析和优化热传导、热辐射和热对流等热问题。
通过模拟物体的温度分布和热流动，可以评估物体的热性能和热耗散效果。
4. 有限元分析结果有限元分析的计算结果可以提供丰富的信息，帮助工程师和科学家理解和优化系统的行为和性能。
以下是一些常见的有限元分析结果：4.1 应力分布通过有限元分析，可以得到结构或部件内的应力分布情况。
这对于评估结构的强度和安全性非常重要，并可以指导优化设计。
4.2 变形分析有限元分析可以给出结构或部件的变形情况。
Finite Element Analysis of Crack Propagation and Casing Failure Process under Thermal Mechanical CouplingQinjie Zhu1, a, Shoukang Hu1, b and Yanhua Chen2, c1Research Center of Earthquake Engineering, Hebei United University,46 Xinhua West Road, Tangshan 063009, China2College of Civil Engineering and Architecture, Hebei United University,46 Xinhua West Road, Tangshan 063009, Chinaa qjzhu@,b leaf-sawfly@,c cyh427@Keywords: Finite Element, Numerical Simulation, Thermal Mechanical Coupling, Crack Propagation, Casing FailureAbstract. Because the temperature of heat medium in thermal recovery wells is very high, and casing is heated during steam injection process, which has become the main reason of casing failure. Therefore, it is very important to analyze crack propagation and casing failure under thermal mechanical coupling. Three-dimensional finite element model is investigated; geometry model is constructed with native and parasolid method in ADINA. The casing is modeled by native method and strata are modeled by parasolid method, casing are subtracted and merged with strata by Boolean Operation. Gravity and displacement loads are defined in structure model, and temperature load in thermal model. In structural model, casing is treated as thermoplastic material, and strata are treated as hot isotropic material. In thermal model, all materials are treated as heat conduction material. Thermal-mechanical coupling is calculated with the thermo-mechanical coupled analysis solver in ADINA, and casing damage process is calculated. According to the calculating results, the mechanism of casing damage is analyzed.IntroductionCasing failure of thermal recovery wells is affected by many factors, such as material characteristics of casing, strata characteristics, faults movement, and so on. In steam rejection, temperature of heating steam is very higher, and heat transfer exists in casing-surrounding system. So the effect of Thermal Mechanical Coupling (TMC) is serious, which makes casing deformed. Based on linear elastic fracture mechanics, elasto-plastio fracture mechanics, and finite element methods, most researchers analyzed pipeline fracture with crack of pipeline, loads, temperature and stress field considered [1-3]. Sanjeev Saxena analyzed elastic-plastic fracture mechanics based prediction of crack initiation load [4]. Considering static load, bending load and cyclic load, LBB(Leak-before-break) and crack propagation are investigated [5-7].Early in the 1980s, Grebner et al took the pipeline as elastic-plastic material and calculated the leakage area of cracking pipeline by finite element method [8]. S.P.Liu analyzed the leak-before-break and plastic collapse behavior of statically indeterminate pipe system with circumferential crack [9]. YukioTakahashi analyzed leak-before-break methodology for pipes with a circumferential though-wall crack [10]. Using finite element method, Xue et al investigated the effects of internal fluid and its pressure on temperature and stress of internal and external surface of pipeline by comparing internal fluid in pipeline with no internal fluid during the welding process [11]. In thermal recovery wells, casing failure is affected by strata and geological condition [12]. The interaction between casing and strata should be considered.Considered the influences of casing material, geological condition and surrounding environment,3-D finite element whole model of casing-strata is established. Stress and strain of casing are analyzed,Thermal Mechanical Coupling FormulationBecause a temperature difference between fluid in thermal recovery wells and strata exists, heat transfer can be taken place among fluid, casing and strata. It can be assumed that the material of the casing obey Fourier’s law of heat conduction,x k q ∂∂−=θ(1) Where, q represents heat flux (heat flow conducted per unit area); θ represents temperature; k represents thermal conductivity (material property). The minus sign indicates the opposite direction to the decreasing of heat flux.For a three-dimensional solid body in the principal axis directions x, y, and z, there are,z k q y k q x k q z z y y x x ∂∂−=∂∂−=∂∂−=θθθ,, (2)where q x , q y , q z and k x , k y , k z are the heat fluxes and conductivities in the principal axis directions. Then equilibrium of heat flow in the interior of the body can be obtained as,B z y x q z k z y k y x k x −=∂∂∂∂+∂∂∂∂+∂∂∂∂()()(θθθ (3) Where q B is the rate of heat generated per unit volume.The above equations are fit for steady-state. For unsteady-state, time-dependent temperature distribution should be considered. It can be expressed byτθd d c q C = (4) Where c is the material heat capacity; τ is time. q C is explained as forming part of the heat generation term q B ,τθd d c q q B B −=~ (5)In which q ~B does not include any heat capacity effect.One of the main thermo-mechanical effects for buried thermal pipeline is heat transfer between contacting bodies. Contact heat transfer is governed by an equation similar to that used for convection boundary conditions.Contact heat transfer is governed by an equation similar to that used for convection boundary conditions: the heat entering contacting body I is,)(ˆIJ I c h q θθ−= (6) where h ˆ is the contact heat transfer coefficient, J θand I θare the surface temperatures of the contacting bodies. In the limit as approaches infinity, the temperatures of the contacting bodies become equal to each other. With h ˆ large, equation (6) can be considered to be a penalty method approximation to the equation I J θθ=.So it is necessary to alternately solve the thermal and structural models until convergence is reached. Fully coupled thermo-mechanical problems can be performed with ADINA-TMC. Modeling for Thermal mechanical couplingCasing failure is affected by casing material, fluid behavior, strata condition, construction quality and so on. Considered casing, strata and temperature synthetically, finite element analysis models underof a finite element model performed by ADINA-T can be used to generate temperatures for a displacement and stress analysis with ADINA.Structure model. Geometry model includes casing model and strata model that are determined by Strata condition. Strata model is constructed with Parasolid method, which is obtained through Boolean Operation from a cuboid, and geometric position for strata must be subtracted in this model, then casing geometry model is constructed with Native method. Gravity and displacement load are applied; inlet and internal wall of casing are fixed. There are many optional elements in ADINA, and 3-D element is selected in this model in order that thermal-mechanical coupling is solved. Finally, element groups are defined and geometry model is meshed, which is shown as figure 1.Fig. 1 Structure model Fig. 2 Influence of Steam Injection Times Thermal model. In order to keep the compatibility between structure and thermal model, thermal model is obtained by copying the geometry model from ADINA Structure to ADINA thermal. So geometry model is the same as structural model. Because thermal convection is considered, 3-D convection elements are placed for both casing and strata.Model Preferences. In structural model, casing material is defined as thermoplastic material, and strata is treated as thermal isotropy material.In thermal model, convection material is defined, and other model parameters are the same with structural model.Thermal mechanical couplingDuring thermal-mechanical coupling, at the beginning of each time step, the structure model is solved for the displacements using the current temperatures. Then the thermal model is solved for the temperatures using the current displacements. If TMC iterations are not required, the algorithm proceeds to the next step. Otherwise the models are solved using the new current displacements and new current temperatures until convergence in displacements and temperatures is reached. Results AnalysisWith force action, influence of steam injection times on displacement, axial stain and circumferential strain is significance. The axial stain and circumferential strain increase rapidly with steam injection times, and displacement varies periodically. Therefore, strains are affected by both force action and steam injection times. This is shown as figure 2.Influence of temperature on displacement, axial stain and circumferential strain is shown as figure 3. It is can be seen that both displacement and strain varies periodically with temperature increases. When the temperature reaches 345 o C, axial stain and circumferential strain increase rapidly. It is means that temperature is not the main reason for casing failure when it is lower than 345 o C. And when temperature is higher than 345 o C, it will result in the casing failure. Therefore, the temperature of steam injection should lower than 345 o C.By comparison of figure 2 and figure 3, it is found that displacement and strain are mainly affected by steam injection times when heat temperature is low. When the temperature of steam injection isshown as figure 4. The initial crack takes place at the maximum bending area of casing with 0.05m displacement. Crackpropagation take place when displacement reaches 0.01m, and casing failure take place with 0.15m displacement. Therefore, the displacement results in casing failure at last.Fig. 3 Influence of Heat Temperature Fig. 4 Crack Propagation of CasingConclusionsAccording to results of thermal-mechanical coupling for thermal recovery wells, some conclusions are obtained. The axial stain and circumferential strain increase rapidly with steam injection times, and displacement varies periodically. When temperature of steam is lower than 345 oC, it is not the main reason of casing failure. But, when temperature is higher than 345 oC, it will result in the casing failure. In order to protect the casing, temperature of steam injection should be lower than 345 oC, and the times of steam injection should limited. The initial crack takes place at the maximum bending area of casing with 0.05m displacement, and the displacement results in casing failure with 0.15m. AcknowledgementsThis work was financially supported by National Natural Science Foundation of China (50678059), and Natural Science Foundation of Hebei Province (D2010000922, E2009000757, and 09277130D ). References[1] Y. J. Kim, N. S. Huh. Engineering Fracture Mechanics, Vol. 69(2002), p.367.[2] A. Amirat, A. Mohamed-Chateauneuf, K. Chaoui. International Journal of Pressure Vessels andPiping, Vol. 83(2006), p.107.[3] S. Takada, N. Hassani, and F. Katsumi. Journal of Structural Mechanics and EarthquakeEngineering, JSCE, 688(54)( 2001), p.187.[4] S.Sanjeev, D. S.Ramachandra-Murthy. Engineering Structure, Vol. 26(2004), p.1165.[5] Y. S.Yoo, H. Shimano, H., Ji, S. H., et al. SMIRT, 15(5) (1999), p.273.[6] Y. S.Yoo. and K. Ando. SMIRT, 15(5) (1999), p.343.[7] Y. S. Yoo, K. Ando. 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