关键词: MDYB-3, 定向有机玻璃, 穿孔试验, 应变率, 疲劳寿命

Abstract: To understand and evaluate the thermomechnical behavior of MDYB-3 oriented PMMA glass, five different types of mechanical tests are carried out using a CSS44100 universal electromechanical material testing machine, the split Hopkinson technique and an MTS servohydraulic testing machine. These tests include: mechanical isotropic testing; perforation tests; uniaxial compression and tension tests over the strain range from 0.001 s^-1to 2 000 s^-1and at initial temperatures from 218 K to 373 K; and constant amplitude stress controlled fatigue testing with two notch stress concentration factors. The damage and fracture of the deformed samples are also observed by a digital camera and an optical microscope. The results show: ① MDYB-3 oriented PMMA glass has remarkable thermomechanical anisotropic characteristics; ②MDYB-3 oriented PMMA glass exhibits higher hardness and strength along the normal direction of the panel, but it will burst out and scatter into brittle pieces under perforation or impact; ③Its thermomechanical responses depend strongly on strain rates and temperatures, and it also shows severe unsymmetry of mechanic strengths under tension and compression loading; ④The S-N curves of doublenotch sheet specimens demonstrate that the fatigue life is not sensitive to the notch at low maximium amplitude stress levels, and that in cyclic loading, the crack initiaton origin is related with the strength of micro-interbeds. Crack initiation of MDYB-3 oriented PMMA glass may originate from the interbeds or the middle region of the notch edge under cyclic fatigue loading. Finally, the results are analyzed and discussed.

Key words: MDYB-3, oriented PMMA, perforation testing, strain rate, fatigue life