由Tresca和双剪应力两轨迹间误差三角形中线确定的屈服方程

在π平面上,取Tresca屈服轨迹与双剪应力屈服轨迹之间误差三角形的几何中线确定新的屈服轨迹,建立了该轨迹在HaighWestergaard应力空间上的应力方程,称此方程为几何中线屈服方程或简称GM屈服准则·证明了单位塑性功率表达式及其对Mises圆的逼近精度·精度分析与算例表明该准则与Mises准则的最大误差不超过2 9%,平均误差仅为0 95%,比MY(平均屈服)准则的逼近精度提高1%,且它是线性的,其轨迹为与Mises屈服轨迹相交的等边非等角十二边形·该准则的单位体积塑性功率表达式也是线性的·

棱（圆）台中截面面积公式之推广

棱（圆）台中截面面积公式之推广兰州市九中王普光设棱（圆）台上、下底面面积分别为Ｓ１、Ｓ２，中截面面积为Ｓ０，则有中截面面积公式若设棱（圆）台上、下底面面积分别为Ｓ１、Ｓ２，截面面积为Ｓ０，截面与上、下底面间距离之比为λ，比照解析几何中线段的定比分点坐...

斜巷斜交贯通处高差的计算与处理

针对两倾斜巷道实现斜交贯通时，巷道相文处两中线存在高差，提出了应用几何法求算高差的计算方法。

Matrix-Geometric Method Based Unified Delay Analysis for Wireless Relay Networks

A lot of work has been focused on desig-ning and analyzing various cooperative diversity pro-tocols for wireless relay networks. To provide a uni-fied queuing analytic framework, we fonmlate an em-bedded Markov chain, which rams out to be a Quasi-Birth-and-Death （QBD） process. Using the Matrix-Ce-ometric method, we can analyze the average delay in a unified way. Theoretical analysis is validated by simu-lation results. We show that the delay performances of Amplify-and-Forward or Decode-and-Forwaxd （AF/ DF） and incremental AF/DF schemes can be analyzed in the unified way. Thus, we can always choose the best cooperative diversity scheme in different scenari-os for delay minimization.

GM屈服准则求解Ⅰ型裂尖塑性区

用几何中线(GM)屈服准则求解了Ⅰ型裂尖塑性区的形状与尺寸,对比了基于Mises和Tresca准则的求解结果。表明在平面应变条件下,GM准则求解的塑性区面积在Tresca和Mises结果之间,Tresca塑性区面积最大,Mises面积最小,GM塑性区与Mises塑性区非常接近,三者的塑性区均成哑铃状。在平面应力下,GM和Mises塑性区二者仍最接近并为豆芽状,Tresca的塑性区最大。无论平面应力还是平面应变,GM准则计算结果与Mises结果均有最佳接近度。