基于ANSYS的轨道梁支架结构分析

轨道梁支架是某新型跷跷板过山车的核心组成设备之一,为了提高轨道梁支架的承载能力,建立了其三维模型,并运用有限元分析软件ANSYS对轨道梁支架及中心转轴进行了强度分析,验证了结构设计的合理性,为进一步优化设计提供了重要依据。     

桥式起重机轨道梁施工过程中的变形控制

阐述了八钢自制大型桥式起重机轨道梁过程中控制变形的具体措施,满足了轨道梁的质量要求。     

轨道车体端梁型材缺陷改进方案研究

在研究轨道车体典型端梁型材的挤压生产工艺及模具设计的基础上,通过对比试验分析了影响端梁性能及缺陷的工艺参数,阐述了端梁型材生产调控要点,并结合检测结果对模具进行了分析和优化。结果表明,通过扩大前室、降低阻料台,同时适当沉桥能够有效地避免壁厚差大、型腔复杂的端梁型材出现缩尾、焊合不良等低倍缺陷;合理设计模具同时优化棒温及速度是改善端梁型材低倍组织的有效途径。     

1号高炉行车梁及轨道调整

本文针对１号高炉行车在运行过程中所出现的问题，结合宝钢其它地方所出现的类似问题，对其原因作了系统的分析并提出其相应对策，对１号高炉行车所出现的问题作了大量测定和具体处理，对处理后的实际情况和使用效果也作了详细的阐述。     

四梁六轨铸造起重机金属结构应力仿真分析

采用有限元分析方法,对四梁六轨铸造起重机桥架进行应力和变形分析,并对跨中腹板焊缝采用"板到体子模型"方法进行精细分析,得到焊缝处的应力分布状况。分析结果表明:四梁六轨铸造起重机桥架的内主梁跨中是应力和变形最大的部位,当主小车满载位于桥架跨中时,内主梁跨中腹板及加强筋板与下翼缘板连接处焊缝的最大应力均已超过了焊缝的疲劳极限应力,是桥架的危险部位,应经常检查。     

自卸车元宝梁断裂分析

介绍了重型自卸卡车常用元宝梁断裂的分析方法,针对在汽车试验场试验的元宝梁进行了应变应力测试,用三维建模软件CATIA对元宝梁建模,用有限元分析软件ANSYS进行分析,并进行了结构优化设计,从众多方案中选出两种理想的方案,制作样件,并在试验场进行了坏路试验,效果良好。     

用有限元分析加热炉活动梁漏水原因及对策

通过对现场实际情况的调研，建立了加热炉水梁的平面和三维实体模型，并利用ANSYS软件给出的有限元分析结果，确定了水梁产生裂纹的根本原因，即水梁的高度偏差和在高温交变载荷作用下的受力变形。最后，根据有限元的计算结果，将原焊接结构修改为三通方式，提高了焊缝质量．延长了水梁的使用寿命。     

行车梁焊缝开裂原因分析及改进

炼钢坯料间行车梁焊缝不断开裂,通过现场调查及理论计算,分析了产生问题的根本原因,并制定了改进措施,取得了明显效果。     

不停产大修拦焦车轨道

介绍了在不停产情况下就拦焦车轧道基础不实、轧道严重变形等不同部位故障所采取的不同处理方法。     

板梁组合结构的有限元分析

本文应用ANSYS有限元分析软件对板和T型材组合结构采用多种不同的构模方法,分析在相同载荷和边界条件下各种不同构模方法的计算结果的区别,从而给出了应用该软件在船舶结构分析中应采用的构模方法。     

Investigation of Large Web Fractures of Welded Steel Plate Girder Bridge

Constructed in 1972 with ASTM A36 (250 MPa) steel, a highway bridge in Maryland is comprised of seven welded steel plate girders of a constant web depth of 2,286 mm (90 in.). In March 2003, the web fractures of two steel girders were discovered in a three-span continuous superstructure unit. A full-height web fracture occurred in an interior girder at a cross frame connection plate; and a partial-height web fracture occurred in an exterior girder at an intermediate transverse stiffener next to a cross frame. The investigation of the girder fractures involved fracture surface examination, material testing, fracture mechanics analysis, and comprehensive finite-element modeling for fracture driving forces. The fracture mechanics analysis indicated that a brittle web fracture could occur at a high stress level with either a surface crack or a through-thickness crack of certain dimensions. Finite-element analysis using a global model and submodels investigated three possible causes: (1) localized distortion of the unsupported web gap due to the lateral forces of cross frame members; (2) fabrication induced out-of-flatness of the web plate under in-plane loading; and (3) residual stresses at the fracture origin area due to the stiffener-to-web welds. The investigation concluded that one or a combination of these can result in the high local tensile stresses triggering a brittle web fracture with certain crack dimensions at the fracture origin area. Several retrofit concepts were investigated for their effectiveness in reducing stresses in the fracture origin area. Bridge inspections in the subsequent 6 years after the web fractures have not reported any other cracks in the bridge.     

170穿孔机主传动系统万向接轴承载能力分析

采用三维有限元法结合现场测试数据对某厂170穿孔机主传动系统万向接轴十字轴的承载能力进行了分析,得到了十字轴的最危险截面以及能够承受的最大峰值扭矩和能长期承受的峰值扭矩。该分析结果为现场生产提供了理论依据,保证了生产的顺利进行。     

Dynamic Analysis of Curved Continuous Multiple-Box Girder Bridges

The use of horizontally curved composite multiple-box girder bridges in modern highway systems is quite suitable in resisting torsional and warping effects induced by highway curvatures. Bridge users react adversely to vibrations of a bridge and especially where torsional modes dominate. In this paper, continuous curved composite multiple-box girder bridges are analyzed, using the finite-element method, to evaluate their natural frequencies and mode shapes. Experimental tests are conducted on two continuous twin-box girder bridge models of different curvatures to verify and substantiate the finite-element model. Empirical expressions are deduced from these results to evaluate the fundamental frequency for such bridges. The parameters considered herein are the span length, number of lanes, number of boxes, span-to-radius of curvature ratio, span-to-depth ratio, end-diaphragm thickness, number of cross bracings, and number of spans.     

Undrained Bearing Capacity of Strip Footings on Slopes

The undrained bearing capacity of foundations on or near slopes is commonly calculated using empirical equations or from design charts which have been produced based on limit equilibrium or upper bound plasticity calculations. Many of the available methods do not take account of important parameters that affect the undrained bearing capacity factor, such as the distance of the footing from the slope, the slope height, or the soil properties. This paper presents finite element analyses of strip footings on or near undrained soil slopes performed in order to investigate the influence of the various parameters that affect undrained bearing capacity. The results of the analyses are compared to available methods. It is found that while some of these methods compare well with the finite element results for certain combinations of geometrical parameters and soil properties, they cannot produce sufficiently accurate results as they either do not take account of all of the affecting parameters or are generally not conservative. Based on the finite element results, design charts, equations, and a design procedure are proposed for the calculation of the undrained bearing capacity factor Nc as a function of the undrained shear strength and the bulk unit weight of the soil, the footing width, the distance of the footing from the slope, the slope angle and the slope height.     

Monitoring Steel Girder Stability for Safer Bridge Erection

The collapse of the State Route 69 Bridge over the Tennessee River near Clifton, Tennessee, is an example of how instability and lateral torsional buckling failure of a single steel bridge girder during erection might cause collapse of the whole steel superstructure. Close attention should be given to the stability of steel plate girders during erection when the lateral support provided to the compression flange might temporarily not be present. Rules of thumb in use today have been adopted by contractors/subcontractors to check the stability of cantilever or simply supported girders under erection using the L/b ratio, where L is the unbraced length and b is the compression flange width. For each girder section, a maximum L/b ratio exists beyond which lateral torsional buckling failure would occur under girder self-weight. Parametric studies were conducted following the latest AASHTO LRFD code in order to indentify the maximum L/b ratio for various girder sections and check the rules of thumb, as well as determine the dominating section parameters on girder stability under erection. Advanced nonlinear finite-element analyses were also conducted on a girder section for both the cantilever and the simply supported case in order to further understand the behavior of girder instability due to lateral torsional buckling under the self-weight, as well as to develop a trial-and-error methodology for identifying the maximum L/b ratio using computer analysis. At the same time, the effect of lateral bracing location on the cantilever free end has been investigated, and it turned out that bracing the top tension flange would be more effective to prevent lateral torsional buckling than bracing the bottom compression flange.     

Full-Scale Test and Analysis of a Curved Steel-Box Girder Bridge

Since the first edition of the AASHTO Guide Specifications for Horizontally Curved Steel Girder Highway Bridges was published in 1980, there have been two more editions including many revisions to the specifications. Some changes were based on valid research results and others were based on limited or uncertain research results and information. The current edition of the specifications contains provisions that may result in unreasonably conservative load capacity ratings. In this paper, the results of field tests and analyses conducted on the Veterans’ Memorial curved steel-box girder bridge are discussed. Test and analytical results show: (1) current AASHTO guide specifications regarding the first transverse stiffener spacing at the simple end support of a curved girder may be too conservative for bridge load capacity ratings; (2) current AASHTO guide specifications may greatly overestimate the dynamic loadings of curved box girder bridges with long span lengths; and (3) a plane grid finite-element model of about 20 elements per span in the longitudinal direction can be used to analyze curved multigirder bridges with external bracings located only over supports. The research results are instructive and applicable to bridge design and bridge load-rating activities.     

大型焦炉炉柱承载能力的分析

炉柱是安装在焦炉外部的护炉设备,它能向焦炉砌体施加一定的保护性压力,使焦炉砌体完整严密.炉柱上下两端由横拉条固定,在水平方向主要承受焦炉砌体的反作用力.将炉柱简化为承受均布载荷或集中载荷的简支梁来校核其强度,能为其横截面设计提供依据.     

百米U75V钢轨矫直前冷却过程弯曲变形的有限元分析

通过研究百米钢轨冷却的边界条件,采用三维瞬态非线性有限元法计算分析了百米U75V平直钢轨矫直前冷却过程中的弯曲变形变化规律。结果表明,平直钢轨在冷却过程中的弯曲变形是一个循环反复的过程,但钢轨最终是弯向轨头的;在考虑钢轨与冷床摩擦作用的情况下,平直钢轨终冷后,其变形特点是中间平直、两端弯曲,端部弯曲范围约为18 m。     

Undrained Bearing Capacity of Two-Strip Footings on Spatially Random Soil

A probabilistic study on the interference of two parallel rough rigid strip footings on a weightless soil with a randomly distributed undrained shear strength performed. The problem is studied using the random finite element method, where nonlinear finite element analysis is merged with random field theory within a Monte Carlo framework. The variability of undrained shear strength is characterized by a lognormal distribution and an exponentially decaying spatial correlation length. The estimated bearing capacity statistics of isolated and two footings cases are compared and the effect of footing interference discussed. Although interference between footings on frictionless materials is not very great, the effect is shown to be increased by soil variability and spatial correlation length.     

轧机主传动减速机轴承的应力分析

以某轧机主传动减速机的调心滚子轴承为研究对象,建立轴承的有限元模型;滚子与内外圈滚道之间通过建立三维实体面—面接触对来传递力和位移,可较真实地模拟轴承的受力状态。通过有限元方法对轴承元件进行接触应力分析计算,得到轴承各元件的变形和应力分布,找出轴承滚子破裂的原因。