关于建筑力学的两个命题

Two propositions on building mechanics

针对建筑力学中的三力平衡汇交定理和正n边形截面的惯性矩两个命题 ,提出了应该对三力平衡汇交定理的条件加以修正 ,即对三力平衡问题中的“三力平行”这种特殊情况不必设条件加以限制 ,并从理论上加以证明。对正多边形截面关于形心轴的惯性矩的特性及计算公式进行了讨论与证明。

Aiming at the two propositions (the theorem of three concurrent forces balance and the inertia moment of multimetric polygon), the paper represents and theoretically proves that the condition of three concurrent forces' balance should be modified, i.e. there's no need to set up conditions to restrict the instance of three forces' parallel. It also discusses and proves the inertia moment characteristics of multimetric polygon section and calculation formula.