有机玻璃受弯构件抗弯承载力试验研究与设计方法

Tests and Design on the Bending Capacity of Flexural Acrylic Beams

为了研究有机玻璃受弯构件的破坏模式及抗弯承载力,对有机玻璃材料及受弯构件力学性能进行了试验研究,获得了材料力学性能参数、构件破坏模式和承载力,并通过数字图像相关(DIC)技术测量了构件中的应变分布。试验研究表明:有机玻璃材料具有一定的拉压不对称性,受压强度高于受拉强度;受弯构件的破坏模式以受拉边缘拉断和受压区爆裂为主,以受拉区最大应变达到极限拉应变为破坏标志;跨中截面正应变符合平截面假定,中和轴略偏向于受压区。分别采用弹性、弹塑性和简化模型计算截面的抗弯承载力和跨中挠度。分析表明:弹性模型的预测值低于试验值,而弹塑性模型和简化模型的计算结果与试验值吻合较好,但简化模型计算更简便,建议用于有机玻璃受弯构件的承载力和跨中挠度计算。

In order to study the failure mode and the bending capacity of fluxural acrylic beams,a series of tests were conducted on the acrylic and flexural members,so as to obtain the material properties,failure modes and bending capacity.Besides,the DIC technology was used to obtain the full-field strain distribution.Test results indicated that PMMA had asymmetric material properties,and compression strength was higher than tensile strength.The combination of the fracture in tension zone and burst in compression zone was the major failure mode,and the failure would happen when the tensile strain reached the ultimate strain in tension.The strain distribution in the mid-span met the plan-section assumption,and the neutral axis was slightly above the centroid of the cross-section.Elastic model,elastic-plastic model and simplified model were used to calculate the bending capacity and deflection.Analysis showed that the predictions of elastic model were lower than the test results,while the predictions of elastic-plastic model and the simplified model matched the test result well.It was recommended to use the simplified model to predict the bending capacity and deflections of flexural acrylic beams due to convenient in calculation.