U型玻璃的安全性
U型玻璃安全性研究的必要性
U型玻璃是一种异型玻璃制品，普通的钢化炉很难对其进行钢化处理（成品率低和钢化均匀性差）。因此，在国内绝大部分应用的U 型玻璃是退火玻璃而不是钢化玻璃。钢化玻璃是安全玻璃，而退火玻璃不是安全玻璃，因而普通U 型玻璃的应用受到限制。但是U 型玻璃是一种形状和性质都很特殊的制品，与普通平板玻璃有很大差异。所以，有必要对普通U 型玻璃的安全性做细致的研究，以便为建筑设计、产品应用提供充分的依据。本研究报告所提及的U 型玻璃，均指未经钢化处理的普通U 型玻璃。
U型玻璃安全性研究的技术路线
玻璃的安全性主要是指玻璃抗破坏的能力及破坏后对人身伤害的程度。现有有关玻璃的国际及国内标准中，一般用弯曲强度、落球冲击性能、霰弹袋及双轮胎冲击性能3项试验指标来衡量（钢化玻璃还有碎片状态指标）。本研究中，也主要以此3项试验为基础，通过合理的试验方案设置（详见第四章），来对U 型玻璃的各项有关安全性指标进行详尽测试。作为对比，将对平板玻璃（浮法玻璃、钢化玻璃）进行相同条件下的检验。通过实验数据的对比、分析，对U 型玻璃的安全性作出客观的评价。
U型玻璃安全性试验研究
承载力及弯曲强度
1.试样及试验方案
2.试验结果（略）
3.试验结果分析
玻璃承载力和弯曲强度可以表征其抵抗静荷载的能力，如建筑玻璃的风荷载、雪荷载及结构应力、安装应力等。承载力是玻璃制品整体破坏前所能承受的最大负荷，是力的单位；抗弯强度是玻璃破坏前单位截面积上所能承受的最大应力。
从U 型玻璃和平板玻璃的弯曲强度，发现翼面朝上时，其强度仅为浮法玻璃强度的1/2左右，是钢化玻璃强度的1/6左右；翼面朝下时，其强度略大于浮法玻璃的强度，大致是钢化玻璃强度的1/3。
U型玻璃的强度计算考虑了其两翼的截面积，加之其压延生产工艺造成的微缺陷较多，所以强度比浮法玻璃要低。考虑U 型玻璃在实际建筑设计和应用时，往往只按腹板面积计算承载，所以在此也按同投影面积（即只按承载力和腹板面积）计算了U 型玻璃强度，我们称之为等效弯曲强度。
按此计算6mm厚U 型玻璃强度，翼面朝上时，其强度为浮法玻璃强度的8倍，为钢化玻璃强度的3倍；翼面朝下时，其强度为浮法玻璃强度的4倍，为钢化玻璃强度的1.5倍；7mm厚U 型玻璃强度还要更高一些。
落球冲击
1.试样及试验方案
试验方案：落球冲击试验的目的是为确定玻璃或玻璃构件是否保持某一最低强度或黏结强度（对夹层玻璃）。
在以下标准中涉及了玻璃的落球冲击。在G B 15763.2-2005《建筑用安全玻璃第2部分：钢化玻璃》标准中，是用1040g 钢球在1m 高度进行冲击；在G B 15763.2-2009《建筑用安全玻璃第3部分：夹层玻璃》标准中，是用1040g 和2260g 钢球在各个高度冲击夹层玻璃，看其在玻璃破碎后胶片是否暴露；在G B 9656-2003《汽车安全玻璃》标准中，有两个落球冲击试验：一个是用2260g 钢球在4m 高度冲击夹层玻璃，看其是否穿透；一个是用227g 钢球冲击夹层或钢化玻璃，冲击高度根据玻璃品种和厚度确定，钢化玻璃的冲击高度为2m 或2.5m ，夹层玻璃冲击高度在8.5m ~12m ，看钢化玻璃是否破碎或夹层玻璃剥落碎片质量是否超标。以上标准均等同或修改采用国际标准，在指标上与国际标准完全一致。
在综合以上标准要求的情况下，制定如下试验方案：分别采用227g 、1040g 和2260g 钢球，对U 型玻璃构件的冲击点进行冲击，冲击高度由低到高逐渐增加，直至构件的上片玻璃破碎或构件穿透。作为对比，对610mm×610mm的浮法玻璃及钢化玻璃进行落球冲击试验，冲击高度由低到高，直至破碎。
2 .试验结果
U型玻璃采用压延方法生产，相对于浮法工艺，其表面及玻璃内部含有更多的微缺陷，因而在受到机械力如冲击等作用时相对容易损坏。从U 型玻璃冲击试验结果和平板玻璃冲击试验结果的比较可以看出，U 型玻璃冲击破碎高度比同厚度的平板玻璃略低，这主要是由该产品生产工艺所决定的。对于由U 型玻璃组合的构件，在腹板中心和边缘的冲击破碎高度大致相同。
U型玻璃通常组合成构件使用，当采用搭扣形式组合时，虽然上片的破碎高度和单片时相同，但整个构件的穿透高度大大提高。两块6mm或7mm厚U 型玻璃227g 钢球的穿透高度达到7000mm，相当于6mm钢化玻璃的抗冲击水平；1040g 钢球的穿透高度达到1000mm以上，相当于8mm浮法玻璃的抗冲击水平；6mm厚U 玻搭扣构件2260g 钢球的穿透高度达到800mm，相当于6mm浮法玻璃的抗冲击水平。
当U型玻璃腹板内侧贴有有机膜时，227g 钢球的穿透高度达到12000mm以上，相当于8mm以上钢化玻璃的抗冲击水平（受试验设备限制，12m 是最高冲击极限）；1040g 钢球的穿透高度达到7000mm以上，相当于8mm钢化玻璃的抗冲击水平。
U型玻璃是一种建筑型材，通过弯折的两翼达到了普通平板玻璃所没有的特殊性能：
1.优异的承载能力：翼面朝向影响承载力的大�。砻媸苎褂ακ盪 型玻璃承载力是受张应力时的1.5～2倍。承载力随玻璃厚度增加而增加，7mm厚U 型玻璃承载力是6mm的1.6～2.2倍。和同投影面积的浮法玻璃及钢化玻璃相比，U 型玻璃具有优异的承载能力：翼面受压应力时U 型玻璃承载力是同厚度浮法玻璃的8.8倍，钢化玻璃的2.8倍；翼面张压应力时U 型玻璃承载力是同厚度浮法玻璃的4.4倍，钢化玻璃的1.7倍。
2.高的等效弯曲强度：翼面受张应力时U 型玻璃的弯曲强度是翼面受压应力时的2倍；强度是材料特性的表征，U 型玻璃的弯曲强度与厚度无关。翼面受张应力时U 型玻璃的弯曲强度与同厚度浮法玻璃相当；翼面受压应力时U 型玻璃的弯曲强度是同厚度浮法玻璃的1/2。按同投影面积计算的U 型玻璃的弯曲强度，翼面受压应力时是同厚度浮法玻璃的8倍；翼面受张应力时是同厚度浮法玻璃的4倍。
U型玻璃采用搭扣方式组合使用及贴膜时，提高了构件抗穿透性能：
U型玻璃抗落球冲击、霰弹袋冲击及双轮胎冲击能力略低于同厚度浮法玻璃。
当U型玻璃搭扣组合使用，尤其是贴有有机膜时，其抗落球尤其是小钢球穿透能力大大增强，内片玻璃破坏载荷高度远高于同厚度钢化玻璃；霰弹袋冲击及双轮胎冲击时，贴膜玻璃构件内片玻璃破坏载荷高度相当于同厚度浮法玻璃。
U型玻璃作为独立单元组成构件用于建筑，在受到冲击破坏时，呈现单元破坏的特征：
即仅冲击点所在的U 型玻璃破坏，周边玻璃单元保持完好。相比普通玻璃构件具有破坏范围小的特点，有助于降低玻璃破碎时对人员的伤害程度。
The necessity of study on the safety of u-shaped glass is a kind of special-shaped glass product, which is difficult to be tempered by ordinary tempering furnace (low yield and poor tempering uniformity) . Therefore, the majority of u shaped glass used in China is annealed glass, not toughened glass. Toughened glass is safety glass, but annealed glass is not safety glass, so the application of ordinary u glass is limited. However, u-shaped glass is a very special shape and properties of the products, and ordinary flat glass is very different. Therefore, it is necessary to do a detailed study on the safety of ordinary u-shaped glass in order to provide a sufficient basis for architectural design and product application. The u-shaped glass mentioned in this study refers to ordinary untempered u-shaped glass. The technical route of U-GLASS safety research, the safety of glass mainly refers to the ability of glass to resist damage and the degree of personal injury after damage. The existing international and domestic standards for glass are generally used to measure the bending strength, drop-ball impact performance, shotgun bag and twin-tire impact performance (toughened glass and debris state) . In this study, based on these three tests, the safety indexes of U-GLASS are tested in detail by reasonable test scheme (see chapter 4) . For comparison, flat glass (float glass, toughened glass glass) will be tested under the same conditions. Through the comparison and analysis of the experimental data, the security of u-shaped glass is objectively evaluated. Safety test of u-shaped glass, bearing capacity and Bending Strength 1. Sample and test plan 2. The result of the experiment. The test results show that the load-carrying capacity and bending strength of glass can be used to describe its resistance to static load, such as wind load, Snow load, structural stress, installation stress, etc. . The bearing capacity is the maximum load and the unit of force that the glass can bear before the whole glass is destroyed, and the bending strength is the maximum stress that the glass can bear on the unit section area before the glass is destroyed. From the bending strength of U-GLASS and plate glass, it is found that the strength of the wing is only about 1 / 2 of that of the float glass and about 1 / 6 of that of the toughened glass glass when the wing face is up, and that when the wing face is down, it is slightly stronger than float glass and is roughly a third the strength of toughened glass. The strength of u-shaped glass is lower than that of float glass because of the cross-sectional area of both wings and the micro-defects caused by calendering process. Considering the fact that u-shaped glass is usually only calculated by the area of web in the actual design and application of buildings, the strength of u-shaped glass is also calculated by the same projection area (that is, only by the bearing capacity and the area of Web) , we call this equivalent bending strength. According to this calculation, the strength of 6 mm thick U shaped glass is 8 times as strong as that of float glass and 3 times as strong as that of toughened glass glass when the wing face up, and 4 times as strong as that of float glass and 1.5 times as strong as that of toughened glass when the wing face down The 7 mm thick U-GLASS is even stronger. Drop Shot 1. The object of a drop-ball impact test is to determine whether a glass or glass member maintains a certain minimum strength or bond strength (for laminated glass) . The impact of a falling ball on glass is covered in the following standards. In GB 15763.2-2005, safety glass for buildings-part 2: toughened glass, 1040g steel balls are used for impact at 1 m height; in GB 15763.2-2009, safety glass for buildings-part 3: Laminated Glass, 1040g and 2260g steel balls are used to impact laminated glass at various heights to see if the film is exposed after the glass is broken, there are two drop impact tests: one is to impact laminated glass with a 2260g steel ball at a height of 4M to see if it penetrates; the other is to impact laminated glass or toughened glass with a 227g steel ball, the impact height being determined according to the type and thickness of glass, the impact height of the toughened glass is 2m or 2.5 m, and the impact height of the laminated glass is 8.5 m ~ 12m, to see whether the toughened glass is broken or whether the quality of the laminated glass flakes exceeds the standard. All the above standards are equal to or modified to adopt international standards, and are fully consistent with international standards in terms of indicators. In the case of synthesizing the above standard requirements, the following test schemes are formulated: Steel Balls of 227g, 1040g and 2260g are respectively used to impact the impact points of u-shaped glass members, and the impact height increases gradually from low to high, until the upper piece of glass of the member breaks or the member penetrates. As a contrast, the impact test of 610mm 610mm float glass and toughened glass was carried out, and the impact height was from low to high, until it was broken. 2. The results show that U-GLASS is produced by calendering method, and its surface and interior of glass contain more micro-defects than that of float process, so it is easy to be damaged by mechanical force such as impact. From the comparison between the impact test results of u-shaped glass and flat glass, it can be seen that the impact crushing height of u-shaped glass is slightly lower than that of flat glass of the same thickness, which is mainly determined by the production process of the product. For u-shaped glass composite members, the impact fracture height at the center and edge of the web is approximately the same. U-shaped glass is usually combined to form a component, when using the form of HASP combination, although the upper piece of the same breaking height and single piece, but the penetration height of the whole component is greatly enhanced. The penetration height of 227g steel balls with thickness of 6 mm or 7 mm u glass is 7000mm, which is equivalent to the impact level of 6mm toughened glass, and that of 1040g steel balls is over 1000mm, which is equivalent to the impact level of 8mm float glass The penetration height of 2260g steel ball of U Glass Hasp with thickness of 6mm is 800mm, which is equivalent to the impact resistance level of 6mm float glass. When the inner side of u-shaped glass web is covered with organic film, the penetration height of 227g steel ball is over 12000mm, which is equivalent to the impact resistance level of over 8mm toughened glass (limited by test equipment, 12m is the maximum impact limit) ; The 1040G steel ball has a penetration height of over 7000mm, which is equivalent to the impact resistance level of 8mm toughened glass. U-shaped glass is a kind of building material, through the bending of the two wings to achieve ordinary flat glass does not have the special performance: 1. Excellent load-bearing capacity: the load-bearing capacity of u-type glass under compressive stress is 1.5 ~ 2 times of that under tensile stress. The bearing capacity of 7 mm thick u-shaped glass is 1.6 ~ 2.2 times of 6 mm. Compared with the float glass and the toughened glass glass with the same projection area, the u-type glass has excellent bearing capacity: 8.8 times and 2.8 times as much as the float glass with the same thickness under compressive stress on the wing surface; The load carrying capacity of u-type glass is 4.4 times and 1.7 times of that of float glass with the same thickness under tension and compression stress on the wing surface, respectively, compared with that of toughened glass glass. 2. High Equivalent Bending Strength: The bending strength of u-type glass under tensile stress is 2 times as that of the wing under compressive stress; the strength is a characterization of material properties, and the bending strength of u-type glass is independent of thickness. The bending strength of U-GLASS under tensile stress is equal to that of float glass of the same thickness, and the bending strength of U-GLASS under compressive stress is 1 / 2 of that of float glass of the same thickness. The bending strength of u-shaped glass calculated by the same projection area is 8 times as much as that of the float glass with the same thickness under compressive stress and 4 times that of the float glass with the same thickness under tensile stress. The penetration resistance of u-shaped glass is improved when the u-shaped glass is combined with buckles and coated with film. The impact resistance of u-shaped glass is lower than that of float glass with the same thickness. When U Type Glass Hasp is used together, especially with organic film, the anti-falling Ball, especially small steel ball, can be penetrated more effectively, and the failure load of inner glass is much higher than that of the same thickness toughened glass; The damage load of the inner glass sheet of the laminated glass component is equivalent to the same thickness of float glass under impact of shotgun bag and double tire. U-GLASS as a stand-alone