【作者】 熊晨玲；

【导师】 杨志勇；

【作者基本信息】 武汉理工大学 ， 结构工程， 2010， 硕士

【摘要】 钢筒仓广泛应用于工业和农业领域中散状物料的储存,相对于钢筋混凝土筒仓,其构造简单、施工方便。钢筒仓的仓壁是典型的圆柱薄壳结构,结构受力性能复杂。在储料产生的竖向摩擦力作用下,仓壁很容易发生屈曲破坏,而且仓壁的稳定性在很大程度上受到储料内部法向压力及几何缺陷的影响。储料内力在一定程度上能够降低仓壁的缺陷的敏感性,显著提高仓壁的稳定性强度。当法向压力过大时,仓壁在竖向摩擦力的作用下可能在局部区域发生屈曲,引起结构刚度的损失而使屈曲强度,发生“象腿”破坏。为了提高筒仓的稳定性,传统的方法是在仓壁的表面位置焊接加劲环梁。本文研究一种新的方法——利用纤维增强复合材料(Fiber Reinforced Polymers,简称FRP)粘贴到仓壁的关键位置来提高钢筒仓的稳定性和强度。FRP加固补强技术在各类工程中得到广泛的利用,尤其是混凝土结构。它利用树脂类胶粘剂将纤维增强复合材料粘贴在结构表面,来达到改善结构受力性能的目的。近年来,已有很多学者开始将FRP应用于金属结构的加固,尤其对钢结构加固的研究和应用最为广泛。FRP材料具有良好的材料性能,强度高,自重轻,相对于传统材料具有良好的耐久性等。与在仓壁上焊接加劲环梁相比,FRP加固钢筒仓具有许多突出的优点,如不会导致应力集中、不会产生残余应力、施工方便、维护简单等。本文以碳纤维增强复合材料(CFRP)加固某落地式钢板筒仓为研究对象,采用数值分析方法,包括线性应力分析、特征值屈曲分析、几何非线性分析、弹塑性屈曲分析,对其稳定性能和强度进行了系统的研究。研究表明,CFRP能够提高筒仓的强度和稳定性,CFRP的宽度和厚度是影响筒仓屈曲强度的重要因素,筒仓的屈曲强度随着CFRP的宽度和厚度的增加而增加,其中,增加CFRP的厚度比增加CFRP的宽度对提高筒仓的屈曲强度更加有效。更多还原

【Abstract】 The steel silo is widely used for storage of bulk solid in industry and agriculture. Compared with reinforced concrete silo, it has a lot of advantages such as simple convenient construction, simplified structure and so on.As a typical cylindrical thin shell, the mechanical behavior of silo wall is very complicated. Silo wall is susceptible to buckle under vertical friction force. The geometrical imperfections and internal pressure play a great role in stability performance of silo wall. The internal pressure can reduce the sensitivity of imperfections to silo wall and increase buckling strength in some degree. If the internal pressure is too large, yielding of the wall near the base boundary leads to reductions in flexural stiffness and local amplifications of displacements. The circumferential membrane stress resultants are raised and elastic-plastic buckling occurs. This elastic-plastic instability failure near base boundary is know as elephant’s foot buckling.To strengthen the silo wall against buckling, the tradition method is using a small ring stiffener. This paper presents a novel method of strengthening silo wall against buckling in which a small amount of fiber-reinforced polymer(FRP) composite, used at critical location, can effectively increase the buckling strength. FRP has been broadly used in strengthening structures, especially in concrete structure. It is bonded to surface of structures by adhesive to improve mechanical performance of structures. Many researchers start to use FRP to strengthen metallic structures such as steel structures. FRP composites have superior properties, including a high strength-to-density ratio and superior durability to many traditional materials. Bonding FRP to silo wall has many advantages compared with welding ring stiffener to it, such as no stress concentration, no residual stress, easy to construct and low maintenance.Numerical analyses including linear stress analyses, linear eigenvalue buckling analyses, geometrical nonlinear analyses, elastic-plastic analyses are carried out to investigate the stability behavior and strength of the ground-supported flat bottomed steel silo reinforced with CFRP. The results show that FRP jacketing can effectively improve structure mechanical behavior and increase buckling strength. In addition, the height and thickness of CFRP are main parameter that affect the buckling strength of the silo. The buckling strength of silo will continuously raise with the increase of the height and thickness of CFRP. Increasing the thickness is more effective than increasing the height of CFRP to enhance the stability of silo.更多还原