In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyse...In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyses method. According to the analytical resuhs, a well fracture resistant joint shape of butt joint with center crack has been approved.展开更多
Büeckner Rice weight function method was used to analyse mixed mode fracture of center cracked circular disk subjected to uniaxial compression. Based on Wu Carlsson procedure semi analytical modes Ⅰ and Ⅱ weigh...Büeckner Rice weight function method was used to analyse mixed mode fracture of center cracked circular disk subjected to uniaxial compression. Based on Wu Carlsson procedure semi analytical modes Ⅰ and Ⅱ weight functions were derived from corresponding reference displacement fields and stress intensity factors calculated by finite element method. Normalized mode Ⅰ and mode Ⅱ stress intensity factors, f Ⅰ, f Ⅱ , were derived from the obtained semi analytical weight functions. The results were then fitted into polynomials, the precision is within 0.5%. It is interesting to note that when the inclined angle θ of a crack is less than 15°, the f Ⅰvalues are positive. when θ =15°, the f Ⅰ values are positive for the crack length a varying from 0.1 to 0.7, but when a =0.8, the f Ⅰ takes the negative value -0.51. When θ >15°, all the f Ⅰ values become negative, which denotes that the compression shear mode is achieved at crack tips. These results are very useful in the investigation of mixed mode fracture of brittle materials.展开更多
Using the single crack solution and the regular solution of plane harmonic function, the problem of Saint_Venant bending of a cracked cylinder by a transverse force was reduced to solving two sets of integral equation...Using the single crack solution and the regular solution of plane harmonic function, the problem of Saint_Venant bending of a cracked cylinder by a transverse force was reduced to solving two sets of integral equations and its general solution was then obtained. Based on the obtained solution, a method to calculate the bending center and the stress intensity factors of the cracked cylinger whose cross_section is not thin_walled, but of small torsion rigidity is proposed. Some numerical examples are given.展开更多
Using the single crack solution and the regular solution elf plane harmonic function, the problem of Saint-Venant bending of a cracked cylinder by a transverse force was reduced to solving two sets of integral equatio...Using the single crack solution and the regular solution elf plane harmonic function, the problem of Saint-Venant bending of a cracked cylinder by a transverse force was reduced to solving two sets of integral equations and its general solution was then obtained. Based on the obtained solution, a method to calculate the bending center and the stress intensity factors of the cracked cylinger whose cross-section is not thin-walled, but of small torsion rigidity is proposed. Some numerical examples are given.展开更多
针对传统的转子结构裂纹故障识别方法中特征提取困难、无法定量识别裂纹深度及受噪声污染严重的问题,提出了一种基于转子轴心轨迹的转子裂纹深度预测模型。该模型基于奇异值分解和卷积降噪自编码器(singular value decomposition-denois...针对传统的转子结构裂纹故障识别方法中特征提取困难、无法定量识别裂纹深度及受噪声污染严重的问题,提出了一种基于转子轴心轨迹的转子裂纹深度预测模型。该模型基于奇异值分解和卷积降噪自编码器(singular value decomposition-denoising convolutional autoencoder,简称SVD-DCAE),能够有效提取裂纹转子的故障特征并准确预测转子裂纹的扩展阶段。将裂纹转子的轴心轨迹作为模型的输入,分别使用仿真数据和实验数据训练和验证模型,并在仿真数据和实验数据中添加随机噪声模拟不同噪声环境。结果显示:所提出模型能够实现转子裂纹扩展程度的准确预测,在弱噪声环境中(信噪比为10 dB)裂纹深度预测准确率高于98%;具有较强的抗噪声能力和鲁棒性,在强噪声环境中(信噪比为-10 dB)预测准确率达到80%,远高于其他经典的卷积神经网络预测模型。展开更多
针对复合材料胶接修补结构,基于TOM理论,提出了一种改进的Rose L R F胶层剪应力分析方法。该方法考虑了金属母板厚度方向上的剪切应力变化,认为剪应力沿厚度方向呈线性变化,并通过有限元数值方法进行了验证,分析了不同厚度的金属裂纹板...针对复合材料胶接修补结构,基于TOM理论,提出了一种改进的Rose L R F胶层剪应力分析方法。该方法考虑了金属母板厚度方向上的剪切应力变化,认为剪应力沿厚度方向呈线性变化,并通过有限元数值方法进行了验证,分析了不同厚度的金属裂纹板组成的修补结构中的胶层剪应力。结果表明,当金属板厚度较薄(板厚与板长之比小于0.1)时,该方法得到的剪应力比Rose L R F给出的结果更接近于有限元解。展开更多
文摘In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyses method. According to the analytical resuhs, a well fracture resistant joint shape of butt joint with center crack has been approved.
文摘Büeckner Rice weight function method was used to analyse mixed mode fracture of center cracked circular disk subjected to uniaxial compression. Based on Wu Carlsson procedure semi analytical modes Ⅰ and Ⅱ weight functions were derived from corresponding reference displacement fields and stress intensity factors calculated by finite element method. Normalized mode Ⅰ and mode Ⅱ stress intensity factors, f Ⅰ, f Ⅱ , were derived from the obtained semi analytical weight functions. The results were then fitted into polynomials, the precision is within 0.5%. It is interesting to note that when the inclined angle θ of a crack is less than 15°, the f Ⅰvalues are positive. when θ =15°, the f Ⅰ values are positive for the crack length a varying from 0.1 to 0.7, but when a =0.8, the f Ⅰ takes the negative value -0.51. When θ >15°, all the f Ⅰ values become negative, which denotes that the compression shear mode is achieved at crack tips. These results are very useful in the investigation of mixed mode fracture of brittle materials.
文摘Using the single crack solution and the regular solution of plane harmonic function, the problem of Saint_Venant bending of a cracked cylinder by a transverse force was reduced to solving two sets of integral equations and its general solution was then obtained. Based on the obtained solution, a method to calculate the bending center and the stress intensity factors of the cracked cylinger whose cross_section is not thin_walled, but of small torsion rigidity is proposed. Some numerical examples are given.
文摘Using the single crack solution and the regular solution elf plane harmonic function, the problem of Saint-Venant bending of a cracked cylinder by a transverse force was reduced to solving two sets of integral equations and its general solution was then obtained. Based on the obtained solution, a method to calculate the bending center and the stress intensity factors of the cracked cylinger whose cross-section is not thin-walled, but of small torsion rigidity is proposed. Some numerical examples are given.
文摘针对复合材料胶接修补结构,基于TOM理论,提出了一种改进的Rose L R F胶层剪应力分析方法。该方法考虑了金属母板厚度方向上的剪切应力变化,认为剪应力沿厚度方向呈线性变化,并通过有限元数值方法进行了验证,分析了不同厚度的金属裂纹板组成的修补结构中的胶层剪应力。结果表明,当金属板厚度较薄(板厚与板长之比小于0.1)时,该方法得到的剪应力比Rose L R F给出的结果更接近于有限元解。
