基于广义塑性理论上界法的有限元法及其应用

实验证明，岩土材料不适应关联流地法则，而应采用非关联流动法则。把广义塑性力学理论引入到极限分析的上界法，据此编制了有限元程序，并引入数学规划方法寻求问题的最小上界解。通过和经典解析解的比较可知，该方法是一种合理有效的方法。     

筒仓侧压力系数对比分析及修正研究

在对比分析各国筒仓设计规范侧压力系数取值的基础上,以弹性理论为基础,考虑了仓壁和储料的弹性变形,导出了侧压力系数的理论计算公式,以此对Janssen公式进行了修正。修正后的公式表明,仓壁和储料的弹性变形对筒仓侧压力系数的取值影响较大,并建议对刚性较大的筒仓侧压力系数采用Janssen公式近似计算,而对于刚度较小的筒仓和金属筒仓则可按修正后的Janssen公式进行计算。     

散料结拱时钢板仓内动态壁面压力的计算和实例应用

考虑钢仓散料结拱和拱面矢高情况推出了仓壁的动压力理论计算公式,并将公式用于模型仓的分析中,其计算值接近试验测试结果。将此公式应用到一大型利浦钢板筒仓工程实例中,其应力和位移结果与静态Janssen公式结果进行比较,说明推导出的动态压力理论公式可用来对钢板仓失效分析,可为工程设计及钢板筒仓应力分析提供参考依据。     

筒仓贮料流态的颗粒流数值模拟

采用基于离散单元法的颗粒流程序建立了一种筒仓缩尺模型,对筒仓缩尺模型进行了静态侧压力的数值模拟,并把模拟结果与原型筒仓的Janssen计算值进行了比较,发现模拟结果与试验和理论值吻合较好,对该模型筒仓进行了卸料过程的模拟,得到了贮料的流动形态.     

大型落地式钢板仓地震作用分析

结合某落地式水泥钢板筒仓工程为例,利用有限元软件ABAQUS建立了三维筒仓模型,采用时程分析法,对钢板仓进行了地震作用分析,根据钢筒仓设计规范,探讨了钢筒仓的抗震性能,为落地式钢板筒仓的抗震设计提供了参考依据。     

考虑地基共同作用的钢板仓结构地震反应非线性时程分析

考虑钢板仓和地基的相互作用和地震时土的非线性,采用有限元程序MARC提供的动力时程分析法,添加邓肯-张非线性地基本构模型,针对不同设防烈度的场地,应用三种典型的地震波形对一个利浦式地基-钢板仓结构模型进行非线性时程响应分析。结果较符合实际,能够描述钢板筒仓的运动特征,并从中发现了一些特点和规律,分析结果可为钢板仓结构工程抗震分析和安全设计提供参考。     

大型落地式钢板筒仓的参数化建模及静力有限元分析

本文研究了基于有限元程序ANSYS的大型落地式钢板筒仓的参数化建模,这种方法可通过输入若干控制参数,快速地完成筒仓结构的建模、加载和计算过程。然后,以某筒仓的实际工程为例,采用编制的语句完成筒仓的静力有限元分析,得到了筒仓结构主要的内力和位移,并对得到的结果进行了分析。     

考虑内压影响的薄壁钢板筒仓屈曲承载力研究

一定程度的内压会降低薄壁钢板筒仓对缺陷的敏感性,提高其弹性屈曲承载力;但内压过高时,筒仓会出现弹塑性强度破坏或弹塑性屈曲破坏,其承载力反而降低。我国现有《粮食钢板筒仓设计规范》（GB50322-2011）给出了考虑内压影响的屈曲承载力计算公式,但该公式只适用于计算内压较低时筒仓的弹性屈曲应力,对高内压下筒仓弹塑性破坏时采用该公式将得到不安全的结果。采用有限元方法对轴压和水平内压作用下有初始缺陷的筒仓进行了参数分析,分别讨论了内压大小、材料强度和径厚比等对筒仓屈曲应力的影响,提出了筒仓在轴压和均匀内压作用下的弹性屈曲应力和弹塑性屈曲应力计算公式,并对《粮食钢板筒仓设计规范》公式进行了修正。经验证,该计算公式与有限元分析结果基本吻合。     

在支座不均匀沉降作用下钢板筒仓的整体受力分析

结合某散粮钢板筒仓工程,通过对钢板筒仓在无支座不均匀沉降作用和有支座不均匀沉降作用的有限元对比分析,得出支座不均匀沉降对筒仓结构整体受力有着较大的影响,并给出了一些有益的建议。     

大型焊接储煤钢板仓的结构设计和稳定性分析

钢板筒仓具有混凝土筒仓无法比拟的优势,其应用已越来越广泛,但其理论研究还相对滞后,尤其对于储煤用大型钢板筒仓的设计尚没有明确的标准指导。结合一拟建储煤钢板筒仓,根据其现场生产条件和工艺要求分析钢板筒仓的结构选型和布置方案;利用Midas/Gen有限元软件建立仓体和仓顶组装成的整体模型,并对其进行结构静力性能的分析,揭示结构在不同受力状态下的应力分布特征和变形特征,验证结构布置的合理性和安全性。利用有限元分析软件ANSYS对仓体分别进行空仓状态和实仓状态下的特征值屈曲分析,发现实仓状态下的第一阶屈曲特征值较空仓状态减小了86.85%;研究水平环向压力对仓体临界承载力的影响,发现实仓在水平环向压力作用下第一阶屈曲特征值提高了89.15%;最后对仓体进行了考虑材料和几何双重非线性的稳定分析,得到结构的实际极限承载能力,发现钢板筒仓是一种非线性非常明显的结构。     

贮料对钢仓壁面静动压力特性的弹塑性分析

考虑地基对筒仓结构的影响，采用Mare有限元程序提供的边界条件高度非线性的接触算法模拟散料对仓壁的作用，对钢板壁面的应力强度和位移变形进行弹塑性分析，将计算结果与应用Jansen静压力理论公式计算出的结果作比较，探讨了非线性接触算法计算结果的可靠性。然后，通过考虑动力效应的侧压力公式对仓壁的动力特性作进一步分析。通过静动力特性分析得出，仓底部位的应力和位移达到最大，对工程设计具有参考意义。     

不同仓底支撑结构形式对大直径筒仓内力的影响研究

对于大直径筒仓,其仓底结构可分为仓底板与仓壁连接在一起和仓底板与仓壁脱开两种形式。本文针对这两种不同的仓底结构形式对筒仓仓壁的应力进行了有限元分析,并对有限元分析结果与传统的无矩理论计算结果进行了比较,表明：不同的仓底结构形式对仓壁的应力影响很大；有限元分析结果比传统的无矩理论计算结果更接近于工程实际情况。     

Behaviour of empty steel grain silos under wind loading: part 1: the stiffened cylindrical shell

This paper presents results of detailed finite element analyses of three empty stiffened steel grain silos under non-uniform wind loading. Three different silo geometries are considered, representing tall, intermediate and shallow silo structures. The structural system of each silo is shown to act as a rather complicated shell-spaceframe system. The roof structural system and the roof wind loading are shown to play a very important role in the overall behaviour of the silos. This paper deals specifically with the behaviour of the tank wall and vertical and circumferential stiffeners. The behaviour of the roof system will be described in a second paper.     

某钢板仓壁节点试验和整体有限元分析

粮食钢板仓壁常用两排螺栓连接节点连接波纹板,而对于波纹板连接中的高强螺栓承载性能,尚缺乏相应的计算公式。首先对一种带橡胶垫圈的高强螺栓连接波纹板,进行连接件的受剪承载能力试验,从而了解该连接件螺栓及波纹板整体的受力性能特性。然后,进行了整体有限元分析。     

Buckling experiments on steel silo transition junctions: II: Finite element modeling

This paper is concerned with the finite element modeling of the experiments on cone–cylinder–skirt–ring transition junctions in steel silos under simulated bulk solid loading presented in the companion paper. Before presenting the finite element results, the issue of modeling the interaction between the stored solid and the shell wall throughout the loading process is first examined. Results from nonlinear bifurcation analyses using the perfect shapes and nonlinear analyses using the measured imperfect shapes are then presented and compared with the experimental results. These comparisons show that despite the structural complexity of steel silo transition junctions, their behavior can be satisfactorily predicted by finite element analyses taking into account a number of important factors including geometric imperfections, effects of welding and the interaction between the junction and the stored solid. Next, the paper presents results of nonlinear analyses of these junctions with assumed eigenmode-affine imperfections. These results shed considerable light on the effect of ring buckling on the load-carrying capacity of transition junctions. Finally, the implications of the experimental and finite element results for the design of steel silo transition junctions are discussed.     

Dynamic FE simulations of buckling process in thin-walled cylindrical metal silos

The buckling of cylindrical steel silos is caused by the wall friction force due to shearing between the silo fill and silo wall. The aim of this paper is to investigate the stability process in a silo composed of thin-walled isotropic plain rolled sheets using a static and dynamic finite element analysis by taking both the geometric and material non-linearity into account during eccentric discharge. Silo shells were subjected to axisymmetric and non-axisymmetric loads imposed by a bulk solid following Eurocode 1. The differences between the results of static and dynamic analyses were comprehensively discussed. The advantages of a dynamic approach were outlined.     

A simplified analytical procedure for assessing the worst patch load location on circular steel silos with corrugated walls

Silos are widely used in the food and chemical industries for the storage of granular materials. The calculation of their wall dimensions is complicated since the interaction between the stored material and that from which the silo is made is complex, a consequence of their very different mechanical behaviours. The loads exerted on the silo walls by stored materials must be taken into account in silo design, and the means for calculating them is contemplated in Eurocode EN 1991-4. The complexity of the phenomena that occur within silos often leads to the appearance of unexpected and asymmetrically distributed pressures. This is taken into account in the above Eurocode via the concept of the patch load, which is asymmetric and can be exerted at any point on the silo wall. A finite element model has been developed in order to check that the stress resultants derived from the patch load on steel silos with corrugated walls may be predicted by using the well-known expressions of shell theory. Then, a simplified analytical procedure has been developed for predicting the worst location of patch loads for all metal silos, but with special application to corrugated steel silos in Action Assessment Class 3. It has been found that significant differences may be found for most cases with the worst location for the patch load defined in Eurocode for welded silos in Action Assessment Class 2. On the other hand, the values obtained for the maximum meridional membrane stress resultant do not significantly differ, except for high slenderness values in intermediate slenderness silos.     

大型筒仓结构与地基的动力相互作用研究

本以某大型筒仓结构为例，考虑到散粒体-结构-地基的相互作用，利用部分集中质量-筒仓耦合相互作用法，对弹性地基上的筒仓结构（包括单体筒仓和筒仓群或排仓）进行了多种工况、系统的有限无动力分析计算。经与刚性地基上的筒仓动力响应的比较，得出以下结论：在对地基施以相同的水平激励时，弹性地基上筒仓的动力响应大于刚性地基上筒仓的动力响应；刚性地基上群仓的动力响应大于单体仓的动力响应；弹性地基上单体仓的动力响应大于群仓的动力响应。     

浅圆仓侧压力计算的虚位移法

浅圆仓散料侧压力一般采用Rankine和Coulomb土压力理论计算,而Rankine理论和Coulomb理论适合于直线挡墙。散体不同于流体,其对侧墙有摩擦力作用,侧压力沿高度的分布不可能是线性的。基于此,依据能量原理,考虑仓壁摩擦,按虚位移法,得到浅圆仓侧压力的计算公式。通过算例,将计算结果与实仓试验结果、Rankine和Coulomb公式计算结果、有限元计算结果进行对比,表明本文计算方法是合理的。