高度不同的中空玻璃破裂行为及热炸裂痕迹研究

The fracture behavior and the thermal breakage trace of hollow glass

对距火源不同高度的中空玻璃破裂行为及热炸裂痕迹进行研究,分析迎火面和背火面的温度、热应力、裂纹形态及玻璃热炸裂痕迹等参数。玻璃板厚度为6 mm,尺寸为600mm×900mm,空气夹层厚度为6mm。对比不同高度处玻璃在5、10、15、20、25、30min的温度变化曲线。结果表明:迎火面和背火面上距离玻璃底端36cm处温度最高。迎火面玻璃在底端热应力较小,容易破裂;背火面玻璃上高度与长度比值约为0.4的位置热应力最小,最容易破裂。迎火面多从底段边缘处开裂,背火面在左右两侧被遮蔽边缘开裂。迎火面玻璃热炸裂后碎片表面无同心纹,形成的裂纹整体呈"蝌蚪"状;背火面玻璃裂纹为树枝状放射性裂纹,短直密集,无同心纹,裂纹断口光滑,断面上未出现弓形纹。

The fracture behavior and the thermal breakage trace of hollow glass under different height away from the fire source were studied. The temperature of the exposed and back sides of the hollow glass, the thermal stress, the glass crack morpholo- gy and the thermal breakage trace of glass were measured and analyzed. The thickness of glass was 6 mm, the size of it was 600 mm× 900 mm, the thickrress of air interlayer was 6 mm. The temperature curves at different height at 5,10,15,20,25, 30 min were analyzed. The results showed that the temperature at the 36 cm from the bottom of the two glass panes were the highest. The thermal stress at the bottom of the glass exposed to the fire was small, the glass was easier to crack at the bot- tom. The minimum value of thermal stress on the back side glass appeared at the location where the ratio of height to the length of glass was 0.4. The glass tended to broke from there. The glass exposed to the fire cracked mostly from the bottom edge, the glass back to the fire cracked mostly from the shelter edge. There were no concentric lines on the fragment of the glass exposed to the fire, the shape of the crack was like ＂tadpole＂; the radioactive crack on the glass back to the fire was short and compact, the fracture was smooth without bow grain characteristics.