Bergan-Wang approach has one governing equation in one variable only, namely the transverse deflection of a moderately thick plate. This approach faces no numerical difficulties as the thickness becomes very small. Th...Bergan-Wang approach has one governing equation in one variable only, namely the transverse deflection of a moderately thick plate. This approach faces no numerical difficulties as the thickness becomes very small. The solution of a fully clamped rectangular plate is presented using two different series solutions. The results of a square plate are compared with the results of the classical plate theory, Reissner- Mindlin theory and the three dimensional theory of elasticity for different aspect ratios. Two types of clamped boundary conditions are investigated. The obtained results show that Bergan-Wang approach gives good agreement for both very thin and moderately thick plates.展开更多
近场水下爆炸会产生复杂的载荷模式,而复杂的边界条件使结构在近场水下爆炸作用下的毁伤形态更加难以预测。因此,采用耦合的欧拉-拉格朗日算法探究了水下爆炸气泡在多边界耦合作用下(自由面、弹塑性板、泥沙边界)的演化过程及其对固支...近场水下爆炸会产生复杂的载荷模式,而复杂的边界条件使结构在近场水下爆炸作用下的毁伤形态更加难以预测。因此,采用耦合的欧拉-拉格朗日算法探究了水下爆炸气泡在多边界耦合作用下(自由面、弹塑性板、泥沙边界)的演化过程及其对固支方板的毁伤效应。首先,开展了2.5 g TNT在不同尺寸(板边长为0.46、0.92和1.61倍最大气泡直径)固支方板底部10 cm起爆的水下爆炸试验,验证了有限元方法的准确性。然后,结合试验和有限元结果分析了不同边界条件下板的毁伤机理。最后,通过系列数值模拟发现:随着板尺寸和爆距的增大,气泡会出现溃散、下射流和上射流3种不同的演化方式;随着板尺寸的增大,爆距对板中心最终变形的影响减小;泥沙边界能减缓气泡收缩,使气泡从中部塌陷形成方向相反的对射流,降低固支方板的位移和应变,对于气泡提前溃散的工况,泥沙边界基本无影响。展开更多
本文讨论固支障碍问题所联系的四阶椭圆交分不等式非协调有限元逼近,在合理的正则性假设下对于广泛的一类非协调板元,其中包括MOrley′s元,第一类及第二类Fraeijs dc Veubcke′s元,Adini′S元,Zicnciwez′s Cloush一Tochcr元,不完全双...本文讨论固支障碍问题所联系的四阶椭圆交分不等式非协调有限元逼近,在合理的正则性假设下对于广泛的一类非协调板元,其中包括MOrley′s元,第一类及第二类Fraeijs dc Veubcke′s元,Adini′S元,Zicnciwez′s Cloush一Tochcr元,不完全双二次非协调WS元得到对应离散问题的误差估计为; ‖u-u_k‖h≤ch^1-1/(2_p)(‖u‖3,p+‖f‖0.p+‖u‖c^2■‖+‖■c^2■)展开更多
文摘Bergan-Wang approach has one governing equation in one variable only, namely the transverse deflection of a moderately thick plate. This approach faces no numerical difficulties as the thickness becomes very small. The solution of a fully clamped rectangular plate is presented using two different series solutions. The results of a square plate are compared with the results of the classical plate theory, Reissner- Mindlin theory and the three dimensional theory of elasticity for different aspect ratios. Two types of clamped boundary conditions are investigated. The obtained results show that Bergan-Wang approach gives good agreement for both very thin and moderately thick plates.
文摘近场水下爆炸会产生复杂的载荷模式,而复杂的边界条件使结构在近场水下爆炸作用下的毁伤形态更加难以预测。因此,采用耦合的欧拉-拉格朗日算法探究了水下爆炸气泡在多边界耦合作用下(自由面、弹塑性板、泥沙边界)的演化过程及其对固支方板的毁伤效应。首先,开展了2.5 g TNT在不同尺寸(板边长为0.46、0.92和1.61倍最大气泡直径)固支方板底部10 cm起爆的水下爆炸试验,验证了有限元方法的准确性。然后,结合试验和有限元结果分析了不同边界条件下板的毁伤机理。最后,通过系列数值模拟发现:随着板尺寸和爆距的增大,气泡会出现溃散、下射流和上射流3种不同的演化方式;随着板尺寸的增大,爆距对板中心最终变形的影响减小;泥沙边界能减缓气泡收缩,使气泡从中部塌陷形成方向相反的对射流,降低固支方板的位移和应变,对于气泡提前溃散的工况,泥沙边界基本无影响。
文摘本文讨论固支障碍问题所联系的四阶椭圆交分不等式非协调有限元逼近,在合理的正则性假设下对于广泛的一类非协调板元,其中包括MOrley′s元,第一类及第二类Fraeijs dc Veubcke′s元,Adini′S元,Zicnciwez′s Cloush一Tochcr元,不完全双二次非协调WS元得到对应离散问题的误差估计为; ‖u-u_k‖h≤ch^1-1/(2_p)(‖u‖3,p+‖f‖0.p+‖u‖c^2■‖+‖■c^2■)
