为获得含Ⅰ-Ⅱ型混合裂纹X80管线钢断裂失效判据,采用含不同角度、不同长度中心裂纹的平板试样测定X80管线钢极限载荷以及断裂位移;同时,采用扩展有限元方法(extended finite element method, XFEM)求解中心裂纹板极限载荷以及裂纹尖端...为获得含Ⅰ-Ⅱ型混合裂纹X80管线钢断裂失效判据,采用含不同角度、不同长度中心裂纹的平板试样测定X80管线钢极限载荷以及断裂位移;同时,采用扩展有限元方法(extended finite element method, XFEM)求解中心裂纹板极限载荷以及裂纹尖端应力强度因子K_(Ⅰ)和K_(Ⅱ),进而按照能量释放率准则计算等效应力强度因子Keq;最后,利用实验测试和数值模拟结果对等效应力强度因子Keq进行了修正,以获得适用于X80管线钢的断裂判据。结果表明:当裂纹长度较小时,裂纹对极限载荷影响不大,X80试样断裂符合韧性断裂特征,随着裂纹长度的不断增加,裂纹对极限载荷影响逐渐增加,当裂纹长度为70 mm时,角度γ=0°的试样极限载荷降低了59.67%,X80管线钢试样断裂符合脆性断裂特征,因此含有Ⅰ-Ⅱ型混合裂纹试样断裂同时兼具韧性和脆性特征,不能直接采用能量释放率准则进行失效判定;计算得到的等效应力强度因子Keq与X80管线钢断裂韧性KIC存在一定差距,通过实验和数值模拟数据拟合得到修正系数A以后,所得失效判据能够很好预测含Ⅰ-Ⅱ型混合裂纹X80管线钢断裂极限载荷,误差小于3.5%。研究结果对于提高处于二维应力状态下的含裂纹板壳结构(如内压作用下油气长输管道)完整性评价结果的准确性具有一定意义。展开更多
Utilizing finite element analysis,the ballistic protection provided by a combination of perforated D-shaped and base armor plates,collectively referred to as radiator armor,is evaluated.ANSYS Explicit Dynamics is empl...Utilizing finite element analysis,the ballistic protection provided by a combination of perforated D-shaped and base armor plates,collectively referred to as radiator armor,is evaluated.ANSYS Explicit Dynamics is employed to simulate the ballistic impact of 7.62 mm armor-piercing projectiles on Aluminum AA5083-H116 and Steel Secure 500 armors,focusing on the evaluation of material deformation and penetration resistance at varying impact points.While the D-shaped armor plate is penetrated by the armor-piercing projectiles,the combination of the perforated D-shaped and base armor plates successfully halts penetration.A numerical model based on the finite element method is developed using software such as SolidWorks and ANSYS to analyze the interaction between radiator armor and bullet.The perforated design of radiator armor is to maintain airflow for radiator function,with hole sizes smaller than the bullet core diameter to protect radiator assemblies.Predictions are made regarding the brittle fracture resulting from the projectile core′s bending due to asymmetric impact,and the resulting fragments failed to penetrate the perforated base armor plate.Craters are formed on the surface of the perforated D-shaped armor plate due to the impact of projectile fragments.The numerical model accurately predicts hole growth and projectile penetration upon impact with the armor,demonstrating effective protection of the radiator assemblies by the radiator armor.展开更多
BV500型可控震源振动器在川渝地区作业过程中,由于平板设计不合理,导致振动能量下传率低、激发信号畸变严重。因此,引入连续体拓扑优化方法,采用固体各向同性材料惩罚(Solid Istropic Material with Penalization,SIMP)模型变密度法,从...BV500型可控震源振动器在川渝地区作业过程中,由于平板设计不合理,导致振动能量下传率低、激发信号畸变严重。因此,引入连续体拓扑优化方法,采用固体各向同性材料惩罚(Solid Istropic Material with Penalization,SIMP)模型变密度法,从降低质量和增加刚度两个方面对BV500型可控震源振动器平板进行优化设计,创新研制了一种“八边形工字钢-20a”平板。优化后平板质量减轻了45.29%,平板刚度提升了79.92%,并开展了优化前后平板激振性能研究。仿真研究结果表明,与原铝合金整体平板相比,“八边形工字钢-20a”平板的能量下传率提高了15.11%,地表接触中心点位移振幅增大了43.74%,互作用力振幅提升了40.56%。现场实验表明,“八边形工字钢-20a”平板激振时,检波器近场信号平均振动速度有效值提升了22.23%,检波器远场信号平均振动速度有效值提升了39%,规律与可控震源道路激振数值仿真模拟结论一致。“八边形工字钢-20a”平板激振性能优于原铝合金整体平板,有效改善了BV500型可控震源在川渝地区道路激振效果。展开更多
文摘Utilizing finite element analysis,the ballistic protection provided by a combination of perforated D-shaped and base armor plates,collectively referred to as radiator armor,is evaluated.ANSYS Explicit Dynamics is employed to simulate the ballistic impact of 7.62 mm armor-piercing projectiles on Aluminum AA5083-H116 and Steel Secure 500 armors,focusing on the evaluation of material deformation and penetration resistance at varying impact points.While the D-shaped armor plate is penetrated by the armor-piercing projectiles,the combination of the perforated D-shaped and base armor plates successfully halts penetration.A numerical model based on the finite element method is developed using software such as SolidWorks and ANSYS to analyze the interaction between radiator armor and bullet.The perforated design of radiator armor is to maintain airflow for radiator function,with hole sizes smaller than the bullet core diameter to protect radiator assemblies.Predictions are made regarding the brittle fracture resulting from the projectile core′s bending due to asymmetric impact,and the resulting fragments failed to penetrate the perforated base armor plate.Craters are formed on the surface of the perforated D-shaped armor plate due to the impact of projectile fragments.The numerical model accurately predicts hole growth and projectile penetration upon impact with the armor,demonstrating effective protection of the radiator assemblies by the radiator armor.
文摘BV500型可控震源振动器在川渝地区作业过程中,由于平板设计不合理,导致振动能量下传率低、激发信号畸变严重。因此,引入连续体拓扑优化方法,采用固体各向同性材料惩罚(Solid Istropic Material with Penalization,SIMP)模型变密度法,从降低质量和增加刚度两个方面对BV500型可控震源振动器平板进行优化设计,创新研制了一种“八边形工字钢-20a”平板。优化后平板质量减轻了45.29%,平板刚度提升了79.92%,并开展了优化前后平板激振性能研究。仿真研究结果表明,与原铝合金整体平板相比,“八边形工字钢-20a”平板的能量下传率提高了15.11%,地表接触中心点位移振幅增大了43.74%,互作用力振幅提升了40.56%。现场实验表明,“八边形工字钢-20a”平板激振时,检波器近场信号平均振动速度有效值提升了22.23%,检波器远场信号平均振动速度有效值提升了39%,规律与可控震源道路激振数值仿真模拟结论一致。“八边形工字钢-20a”平板激振性能优于原铝合金整体平板,有效改善了BV500型可控震源在川渝地区道路激振效果。
