新型玻璃钢冷却塔在甲醇系统中的应用

大力推广高效节能的新型工业冷却塔,分期分批完成对现有落后工业冷却塔的技术改造是节能降耗的有力措施.新型玻璃钢冷却塔具有高效、低阻、节能、操作弹性大、经久耐用等优点,是一种新型实用的工业冷却塔.     

GBT formulation to analyse the behaviour of thin-walled members with variable cross-section

The generalised beam theory (GBT) provides a general solution for the linear/non-linear analysis of prismatic thin-walled structures, using bar elements capable of describing the cross-section rigid-body motions and distortions. Nowadays GBT is fully developed for thin-walled members having a large variety of constant cross-sections. This paper provides the extension of GBT for the special case of thin-walled members with variable open cross-section and the limits of its applicability.     

玻璃钢纤维复合材料横担高周疲劳性能

针对由风致振动引起的输电塔复合材料横担疲劳问题,对6个新型足尺带钢套管的玻璃钢纤维(GFRP)复合材料横担试件进行了高周(50万次)疲劳性能试验研究,监测了试件的受力状态,分析了其荷载-位移-时间曲线和耗能能力的变化.对未发生明显疲劳破坏的试件进行极限承载力试验,得到其剩余极限承载力.基于剩余强度理论评价了试件的累积损伤并对其疲劳寿命进行预测.结果表明:GFRP复合材料横担试件具备良好的抗疲劳性能,最不利荷载工况下的平均疲劳寿命可达550万次,安全裕度较高.     

Combination form analysis and experimental study of mechanical properties on steel sheet glass fiber reinforced polymer composite bar

The concept of steel sheet glass fiber reinforced polymer (GFRP) composite bar (SSGCB) was put forward. An optimization plan was proposed in the combined form of SSGCB. The composite principle, material selection, and SSGCB preparation technology have been described in detail. Three-dimensional finite element analysis was adopted to perform the combination form optimization of different steel core structures and different steel core contents based on the mechanical properties. Mechanical tests such as uniaxial tensile, shear, and compressive tests were carried out on SSGCB. Parametric analysis was conducted to investigate the influence of steel content on the mechanical properties of SSGCB. The results revealed that the elastic modulus of SSGCB had improvements and increased with the rise of steel content. Shear strength was also increased with the addition of steel content. Furthermore, the yield state of SSGCB was similar to the steel bar, both of which indicated a multi-stage yield phenomenon. The compressive strength of SSGCB was lower than that of GFRP bars and increased with the increase of the steel core content. Stress-strain curves of SSGCB demonstrated that the nonlinear-stage characteristics of SSGCB-8 were much more obvious than other bars.     

纯钨棒材锻造和退火工艺研究

采用不同平均锻造比及锻造方式对烧结纯钨棒进行锻造拔长,并在不同退火制度下对锻造后钨棒进行退火,利用金相显微镜、硬度测试仪及密度测试仪对试样微观组织及物理力学性能进行分析,研究结果表明:锻造可显著提高纯钨棒密度及硬度,但平均锻造比过大会导致钨棒出现锻造开裂等现象,在1 450℃下锻造时,平均锻造比应小于32%。与较小平均锻造比、一火一端锻造的钨棒相比,采用较大平均锻造比、一火两端锻造的钨棒的组织更细,硬度更高,HV10可达452.1,在退火时亦需要更高的退火温度及更长的退火时间(1 350℃下退火60 min)才能完成再结晶,且在退火前及退火初期,该工艺锻造的钨棒硬度相对更高,随着回复再结晶的完成,两种锻造钨棒硬度逐渐降低,且硬度差别不再明显。     

冻融循环下BFRP筋与混凝土黏结强度试验研究

为了研究冻融循环作用下BFRP筋与混凝土黏结强度,对不同冻融次数（0、10、20、40次）和不同混凝土强度等级（C30、C35、C40）共36个试件进行冻融循环试验和中心拉拔试验。试验结果表明:未经冻融循环的试件和冻融循环40次（C30）试件发生拔出破坏,其余冻融试件均发生劈裂破坏;随着混凝土强度等级提高,脱胶强度和黏结强度逐渐增加;随着冻融循环次数增加,BFRP筋与混凝土的黏结强度和峰值滑移呈现出先增加后减小的趋势,而脱胶强度随冻融循环次数增加逐渐减小。     

GFRP管钢筋混凝土偏压长柱的试验研究

通过15个GFRP管钢筋混凝土长柱和1个无GFRP管约束的钢筋混凝土柱在偏心受压作用下的试验,研究了其破坏形态及力学性能,并分析了混凝土强度、长径比、偏心距等因素对柱力学性能的影响.试验结果表明,GFRP管的约束作用能有效提高柱的承载力及延性;随着混凝土强度的提高,GFRP管钢筋混凝土柱的承载力和刚度增大;随长径比和偏心距的增大,GFRP管对混凝土的约束效果降低,柱的承载力降低;平截面假定适用于GFRP管钢筋混凝土偏压长柱的计算.     

GFRP圆柱抗侧向弯曲性能试验研究

通过3根GFRP空心圆柱和3根GFRP-混凝土实心柱构件的侧向受弯试验,得到各试件的荷载-位移和荷载-应变关系曲线以及极限荷载。试验结果表明,随着纤维纵横向铺层比例的提高,空心构件的极限承载力以及抗弯刚度均有所提高,而实心构件仅增大极限承载力,但对抗弯刚度影响不大;长径比越小,空心和实心构件的极限承载力和抗弯刚度均增大,且实心构件相比于空心构件的承载力增长幅度较大。     

带预应力约束拉杆R-CFT短柱轴压性能试验研究

为了解约束拉杆预拉力对矩形钢管混凝土短柱受力性能的影响,进行了3个带预应力约束拉杆短柱轴压试验和另外2个对比试验,对比试验试件中1个不带约束拉杆,1个带普通约束拉杆。预应力约束拉杆和普通约束拉杆均由M20高强度螺栓组成,作为普通约束拉杆的高强度螺栓,在构件受轴向压力前与钢管壁焊接成一体;作为预应力约束拉杆的高强度螺栓,在构件受轴向压力前通过扭紧螺帽产生预拉力,然后与钢管壁焊接成一体,由拉杆预拉力对钢管壁和核心混凝土进行预压。试验结果表明,设置约束拉杆后,构件的承载力提高,轴向变形能力增强;与普通约束拉杆相比,预应力约束拉杆能减小构件最大荷载时的变形,但对构件承载能力和后期变形能力影响不大;减小预应力约束拉杆的横向间距,可有效减小构件最大荷载时的轴向变形,提高构件前期刚度,但对构件承载力影响不明显;在截面宽度和拉杆数量不变的情况下,随着截面长宽比的增加,构件后期变形能力减小。     

光纤光栅传感技术在火灾报警系统中的应用

作者通过对光纤光栅火灾报警器原理的介绍,详述了这一新技术在工程应用中的优点,并通过实例分析阐述了该报警器在建筑设计中的应用。