Three-dimensional thermoelastic analysis is presented for an orthotropic functionally graded rectangular plate, which is simply supported and isothermal on its four lateral edges. With the assumption that material pro...Three-dimensional thermoelastic analysis is presented for an orthotropic functionally graded rectangular plate, which is simply supported and isothermal on its four lateral edges. With the assumption that material properties have arbitrary dependence on the thickness-coordinate a Peano-Baker series solution is obtained for the thermoelastic fields of the functionally graded plate subjected to mechanical[ and thermal loads on its upper and lower surfaces by means of state space method. The correctness of the obtained series solution is validated through numerical examples. The influence of different material properties distributions on the structural response of the plate is also studied.展开更多
A thermoelastic problem of a circular annulus made of functionally graded materials with an arbitrary gradient is investigated. Different from previous works, our analysis neither requires a special form of the gradie...A thermoelastic problem of a circular annulus made of functionally graded materials with an arbitrary gradient is investigated. Different from previous works, our analysis neither requires a special form of the gradient of material properties nor demands partitioning the entire structure into a multilayered homogeneous structure. Instead, we propose a new method for solving the thermoelastic problem of a functionally graded circular annulus by transforming it to a Fredholm integral equation. The distribution of thermal stresses and radial displacement can be obtained by solving the resulting equation. Illustrative examples are given to show the effects of varying gradients on the thermal stresses and radial displacement for given temperature changes at the inner and outer surfaces. The results indicate that the thermal stresses can be relaxed for specified gradients, which is beneficial to design an inhomogeneous annulus to maintain structural integrity.展开更多
脉冲电流烧结过程的颈部形成机理,特别是非导电粉末材料,是需要着重研究的核心问题。以非导电Al_2O_3粉末为研究对象,引入L-S(Lord and Shulman)型广义热弹性方程,初步探究烧结初期非导电粉末颈部局部高温形成以及快速烧结机理。利用Com...脉冲电流烧结过程的颈部形成机理,特别是非导电粉末材料,是需要着重研究的核心问题。以非导电Al_2O_3粉末为研究对象,引入L-S(Lord and Shulman)型广义热弹性方程,初步探究烧结初期非导电粉末颈部局部高温形成以及快速烧结机理。利用Comsol Multiphysics模拟得到脉冲电流烧结过程中颗粒内部的温度场和应力场分布以及烧结颈部的化学势和空位浓度变化规律。数值结果表明,热以波的形式在烧结颈部产生叠加,形成局部高温。化学势变化表明:烧结初期表面扩散占主要作用,空位浓度差的突变使烧结颈部产生局部空位浓度梯度,促进烧结颈长过程,缩短烧结时间。展开更多
定量红外热像法,作为一种无损、全场、实时、非接触的测试手段,不仅能够用于对材料内部缺陷的无损检测,而且能够对在役结构的疲劳损伤演化状态进行识别.定量红外热像法还能够快速预测材料的疲劳极限和S-N(stress-number of cycles)曲线...定量红外热像法,作为一种无损、全场、实时、非接触的测试手段,不仅能够用于对材料内部缺陷的无损检测,而且能够对在役结构的疲劳损伤演化状态进行识别.定量红外热像法还能够快速预测材料的疲劳极限和S-N(stress-number of cycles)曲线,实验周期短,成本低.文中较为系统地综述了定量红外热像法的发展现状及应用,讨论了定量红外热像法应用过程中的几个重点问题.最后总结展望了定量红外热像法的未来发展方向及应用前景.展开更多
基金Project supported by the Program for Young Excellent Talents in Tongji University (No. 2009KJ047)the National Natural Science Foundation of China (Nos. 10872150 and 11090334)
文摘Three-dimensional thermoelastic analysis is presented for an orthotropic functionally graded rectangular plate, which is simply supported and isothermal on its four lateral edges. With the assumption that material properties have arbitrary dependence on the thickness-coordinate a Peano-Baker series solution is obtained for the thermoelastic fields of the functionally graded plate subjected to mechanical[ and thermal loads on its upper and lower surfaces by means of state space method. The correctness of the obtained series solution is validated through numerical examples. The influence of different material properties distributions on the structural response of the plate is also studied.
基金supported by the National Natural Science Foundation of China (No. 10672189)
文摘A thermoelastic problem of a circular annulus made of functionally graded materials with an arbitrary gradient is investigated. Different from previous works, our analysis neither requires a special form of the gradient of material properties nor demands partitioning the entire structure into a multilayered homogeneous structure. Instead, we propose a new method for solving the thermoelastic problem of a functionally graded circular annulus by transforming it to a Fredholm integral equation. The distribution of thermal stresses and radial displacement can be obtained by solving the resulting equation. Illustrative examples are given to show the effects of varying gradients on the thermal stresses and radial displacement for given temperature changes at the inner and outer surfaces. The results indicate that the thermal stresses can be relaxed for specified gradients, which is beneficial to design an inhomogeneous annulus to maintain structural integrity.
文摘脉冲电流烧结过程的颈部形成机理,特别是非导电粉末材料,是需要着重研究的核心问题。以非导电Al_2O_3粉末为研究对象,引入L-S(Lord and Shulman)型广义热弹性方程,初步探究烧结初期非导电粉末颈部局部高温形成以及快速烧结机理。利用Comsol Multiphysics模拟得到脉冲电流烧结过程中颗粒内部的温度场和应力场分布以及烧结颈部的化学势和空位浓度变化规律。数值结果表明,热以波的形式在烧结颈部产生叠加,形成局部高温。化学势变化表明:烧结初期表面扩散占主要作用,空位浓度差的突变使烧结颈部产生局部空位浓度梯度,促进烧结颈长过程,缩短烧结时间。
文摘定量红外热像法,作为一种无损、全场、实时、非接触的测试手段,不仅能够用于对材料内部缺陷的无损检测,而且能够对在役结构的疲劳损伤演化状态进行识别.定量红外热像法还能够快速预测材料的疲劳极限和S-N(stress-number of cycles)曲线,实验周期短,成本低.文中较为系统地综述了定量红外热像法的发展现状及应用,讨论了定量红外热像法应用过程中的几个重点问题.最后总结展望了定量红外热像法的未来发展方向及应用前景.
