Flange Angle Research Articles

Test on progressive collapse of steel moment-resisting frame with upper-and-lower flange angle steel connection

Both of test and numerical simulation methods are employed to study the vertical progressive collapse and collapse assessment methods of steel frame under accidental loads. Firstly, a steel frame collapse test model with a geometric similarity ratio of 1:1.5 is designed and manufactured. The ends of column of test model is fixed. The upper and lower flange angle steel connection is used. The far end of the beam is constrained by a controllable sliding hinge support. The various stages of vertical progressive collapse of structures are simulated by a large displacement loads applied at the far end of the beam. The main focus of the testing is to examine the stress and deformation of beam and joint at various stages, particularly the development of stress and deformation in the angle steel attached to the beam-column connection. The development law of collapse load-displacement curve, joint rotation, beam strain, and angle steel strain are analyzed. The structural resistance mechanism and the transformation relationship between resistance mechanisms during collapse are studied. Subsequently, the relationship between the structural dynamic increase factor curve and the structural collapse process is analyzed using finite element method. The results show that the strain of angle steels can better reflect the destruction and deformation process of substructure during the collapse, the collapse resistance mechanism of structure, and the transition between resistance mechanisms.With the help of the characteristic points on the structural dynamic increase factor curve, the collapse limit state of structure can be reliably determined.

Research on heavy-haul adaptive technology and strengthening measures for existing railway steel bridge

PurposeThis research addresses the diverse characteristics of existing railway steel bridges in China, including variations in construction age, design standards, structural types, manufacturing processes, materials and service conditions. It also focuses on prominent defects and challenges related to heavy transportation conditions, particularly low live haul reserves and severe fatigue problems.Design/methodology/approachThe study encompasses three key aspects: (1) Adaptability assessment: It begins with assessing the suitability of existing railway steel bridges for heavy-haul operations through comprehensive analyses, experiments and engineering applications. (2) Strengthening: To combat frequent crack defects in the vertical stiffener end structure of girder webs, fatigue performance tests and reinforcement scheme experiments were conducted. These experiments included the development of a hot-spot stress S-N curve for this structure, validating the effectiveness of methods like crack stop holes, ultrasonic hammering and flange angle steel. (3) Service life extension: Research on the cruciform welded joint structure (non-fusion transfer type) focused on fatigue performance over the long life cycle. This led to the establishment of a fatigue S-N curve, enhancing Chinese design codes.FindingsThe research achieved several significant outcomes: (1) Successful implementation of strengthening and retrofitting measures on a 64-m single-span double-track railway steel truss girder on an existing heavy-duty line. (2) Post-reinforcement, a substantial 26% to 32% reduction in live haul stress on bridge members was achieved. (3) The strengthening and retrofitting efforts met design expectations, enabling the bridge to accommodate vehicles with a 30-ton axle haul on the railway line.Originality/valueThis research systematically tackles challenges and defects associated with Chinese existing railway steel bridges, providing valuable insights into adaptability assessment, strengthening techniques and service life extension methods. Furthermore, the development of fatigue S-N curves and the successful implementation of bridge enhancements have practical implications for improving the resilience and operational capacity of railway steel bridges in China.

Osseous factors influencing distal tibial rotation in biplane medial opening wedge high tibial osteotomy.

There is a lack of studies investigating the distal tibial rotation (DTR) during medial opening wedge high tibial osteotomy (MOWHTO). This study was designed to evaluate osseous factors influencing DTR in patients who underwent biplane MOWHTO. A total of 106 knee joints in 69 patients who underwent surgery for varus malalignment of knee were reviewed. Based on several software, standard and actual hinge positions were defined in pre-operative and post-operative CT data. Pearson's correlation and Spearman's correlation analysis were performed with DTR change as the dependent variable. Independent variables included angles between standard and actual hinge in the sagittal (ASAHS) and axial (ASAHA) planes, pre-operative and post-operative medial proximal tibial angle, opening width (OW), tuberosity osteotomy angle, flange angle (FA), gap ratio, and hinge fracture. The distal tibia rotated approximately 0.35° internally. Pearson's and Spearman's correlation analysis showed that DTR change was associated with ASAHS, OW, and FA. Larger OW and FA resulted in higher external rotation angles. DTR change was significantly associated with ASAHS, followed by OW and FA rather than ASAHA if only considering osseous factors in biplane MOWHTO. The distal tibia tended to rotate externally when the actual hinge was inclined posteriorly to the standard hinge in the sagittal planes, but rotate externally or internally when the actual hinge was inclined anteriorly.

Determination of influential springback parameters in U-bending test

AbstractU-bending tests are the most common method to predict springback and are influenced by the process and geometrical variables in addition to material behaviour. It needs a numerical study at a high level with many variables to reduce try-out time and loop. In this study, the U-bending test of DC01 steel has been researched numerically and experimentally to govern the influential parameters. The numerical analysis was conducted using AutoForm-Sigma code. The die radius has an excessive influence on the change of flange angle than the punch radius, but the punch radius has the greatest influence on the variation of the sidewall angle. The coefficient of friction played a great impact on both flange and sidewall angle deviation and its influence grows stronger as the blank holding force increases.

An Adaptive Algorithm and Additively Manufactured Punch Used to Form Aluminum Sheet Metal Parts.

Self-adaptive mechanisms are gaining momentum in industrial processes. It is understandable that as the complexity increases, the human work must be augmented. Considering this, the authors have developed one such solution for the punch-forming process, using additive manufacturing, i.e., a 3D-printed punch, to draw into shape 6061-T6 aluminum sheets. This paper aims to highlight the topological study used to optimize the punch form shape, the methodology of the 3D printing process, and the material used. For the adaptive algorithm, a complex Python-to-C++ bridge was created. It was necessary as the script has computer vision (used for calculating stroke and speed), punch force, and hydraulic pressure measurement capabilities. The algorithm uses the input data to control its subsequent actions. Two approaches are used in this experimental paper, a pre-programmed direction and an adaptive one, for comparison purposes. The results, namely the drawing radius and flange angle, were statistically analyzed using the ANOVA methodology for significance. The results indicate significant improvements when using the adaptive algorithm.

Tolerance Analysis of Cylindrical Roller Bearing under Combined Radial and Axial Loads

In order to analyze the influence of tolerance values of key parameters for cylindrical roller bearings under combined axial and radial loads, a coupled model, incorporating a dynamic model of cylindrical roller bearings, contact model, and fatigue life model, is developed to investigate the effect of flange angle, roller-end radius, interval of roller length gauge, and roller profile on contact performance and fatigue life. The results show that the grouping design of flange angle and roller-end radius in the tolerance range was helpful for reducing contact ellipse truncation. The difference of the roller length would change the axial load distribution of the bearings. For the longest roller located in the bottom position, the bigger the difference, the bigger the roller tilt angle and carried-axial load. The (0, +2.5 μm) tolerance range of the crown drop can limit the difference of the fatigue life within 20% in the current analysis.

Modeling and Dynamic Analysis of Cylindrical Roller Bearings Under Combined Radial and Axial Loads

Abstract To improve the endurance and reliability of cylindrical roller bearings (CRBs) under complex operating conditions, a dynamic model of CRB is developed. The model incorporates a roller–raceway contact model to optimize roller profile and is further verified with published data. Systematic parametric analyses are conducted to investigate the influence of flange angle, roller-end sphere radius, and roller profile on load distribution, roller tilt, roller skew, and contact performance. The results suggest that high flange–roller contact location and contact stiffness can effectively extend fatigue life of the bearing, while low flange–roller contact location can reduce the heat generation. In addition, roller profile has negligible effect on load distribution, but an optimized roller profile can improve the anti-tilt capacity. The developed model provides a tool for the internal design and frictional loss optimization of CRB under combined loads.

Flow field analysis and testing of curved shroud wind turbine with different flange angle

Flow field analysis and testing of curved shroud wind turbine with different flange angle

Fatigue life analysis of the radial cylindrical roller bearings: roller end-flange construction effect

The fatigue life analysis of radial Cylindrical Roller Bearings (CRBs) is performed by considering the effects of the roller end-flange construction. A NUP-type CRB with the conical flange and the rollers having spherical ends is considered under various combined loads. The effect of the variation of the flange angle on the bearing life is addressed. The slicing method is employed to obtain bearing internal load distribution, and the elastic half-space method is used to calculate contact pressures and subsurface stresses, which are necessary for bearing life calculations. For the combination of radial and axial loading, it’s observed that the bearing life decreases up to a certain value of the flange angle, and the changes in the life are minimal after a certain flange angle. For high misalignment angles of the inner ring with radial loading, the results show that the predicted life decreases until a particular flange angle and then increases with increasing flange angle. The change in the bearing life depending on the flange angle is mainly attributed to the change in the roller tilt angle versus the flange angle.

Effect of cladding material properties on sealing performance of reactor pressure vessel with spherical head

308 L stainless steel is a commonly used cladding material of reactor pressure vessel. Due to the difference of surfacing process, its performance is quite different from that given in the standard. In this study, based on the stress-strain data of cladding 308 L measured in the laboratory, the elastic-plastic analysis of the sealing performance of the spherical head reactor pressure vessel were carried out by ANSYS finite element software. It is shown that the elastic-plastic results of the axial separation of flange, bolt load and flange angle are in better agreement with the hydrostatic test results. In addition, the influence of elastic modulus, yield stress and tangent modulus of the 308 L on the sealing performance of spherical head reactor pressure vessel was also investigated under design condition and transient condition. It is shown that the elastic modulus, yield stress and tangent modulus have a certain degree of influence on the axial separation of gasket, the axial separation of flange, bolt load and flange angle.

Design Optimization of Diffuser Augmented Wind Turbine

The wind turbine power decreases at low wind speed. A flanged diffuser plays a role of a device for collecting and accelerating the approaching wind, and thus the optimization of the diffuser shape presents an important way to enhance the wind turbine power. In this work, a numerical parametric study was conducted on the diffuser to obtain the initial optimum form of flanged diffuser. Then, the Simplex algorithm is used to obtain the optimal diffuser shape starting from the obtained initial shape. Finally, the obtained optimum diffuser shape is used with conventional wind turbine blade. The diffuser shape is defined by four variables: open angle, flange height, centerbody length, and flange angle. The numerical simulation of flanged diffuser is carried out using the “CFDRC package. The results indicated that, the optimum diffuser shape can be obtained using simplex algorithm which maximizes the entrance average velocity to reach 1.77 times wind speed. The power augmented by a factor about 2.76:5.26 of a selected small wind turbine using the obtained diffuser shape compared to that without diffuser.

Reliability-Based Design Optimization of Pump Penetration Shell Accounting for Material and Geometric Non-Linearity

The roof slab of the nuclear reactor supports all the components and sub-systems. Roof slab needs to resist the seismic loads in accordance with load-carrying criteria. The static stress analysis of the reactor roof slab reveals that high-stress concentration was present in the pump penetration shell (PPS) which supports the primary sodium pump. This paper presents the assessment of collapse load and optimization of pump penetration shell, through the reliability approach, accounting for material nonlinearity, geometrical nonlinearity and randomness in loading. In addition to that, the load-carrying capacity of PPS was determined considering two different materials, viz., IS2062 and A48P2. The design of experiments (DoE) was formulated considering the flange angle and flange thickness as parameters. An empirical model for load function was formulated from the results of the collapse load obtained for various combinations of design parameters. The above function was used to perform the reliability-based geometry optimization of PPS of the roof slab.

Conventional I-shape brace member bolted connections under seismic loading: Laboratory study

In many regions of the world, a conventional low-ductility concentrically braced frame (CBF) is commonly chosen as the seismic force resisting system. The energy dissipation is not restricted to yielding and buckling of the braces, as would be required for ductile braced frames; rather, energy dissipation is assumed to occur through localised yielding and friction in connections, as well as limited member yielding. The objective of this study was to characterize by means of laboratory testing the inelastic response of full-scale conventional I-shape braces and their bolted connections under reversed-cyclic seismic loading. Six brace specimens comprising two commonly used bolted connection types, flange plate and flange angle, were designed following the Type CC provisions prescribed by CSA S16. The brace specimens achieved storey drift ratios of 1%–2%, due to inelastic deformations in both the braces and the connections, even though capacity based design provisions were not incorporated in their design. Energy dissipation resulted from overall and local brace buckling, gusset plate buckling, tension yielding of flange plates, angles and gusset plates, block shear failure of brace webs and angles, bolt fracture and fracture of the gusset plates, along with bolt slip. However, the observed performance of these braces and connections in this laboratory based study is not necessarily guaranteed to be replicated for all conventional CBF designs due to the conservative nature and variability in accuracy of the existing CSA S16 design equations that were relied upon to design and detail the test specimens.

Enhancement of springback prediction of AHSS parts by advanced friction modelling

The complex springback behaviour of advanced high strength steel parts makes a robust manufacturing process challenging, mainly in terms of part dimensional accuracy. Therefore, an accurate springback prediction using sheet metal forming simulation is of a great importance to realize reliable forming processes and to achieve the target geometry. An accurate springback prediction requires an exact computation of the elastic stresses from the plastic deformations, which can be influenced among others by the retention of the sheet metal and the frictional properties of the parts. However, the frictional behaviour in the forming process has been often simplified by using a constant friction coefficient in the simulation, which could lead to a significant deviation in the springback prediction. To address this limitation, TriboForm software provides an advanced friction model in which friction is a function of several process setting parameters, namely pressure, strain, temperature and velocity. In this contribution, the advanced friction models for DH800 and CP800 materials are generated. Compared to a constant friction coefficient of 0.15, it is found that the prediction of flange angle of deep drawn hat profiles, produced by several blank holder forces, can increase up to 70% and of the sheet’s draw-in up to 10%.

Rotational Changes in the Distal Tibial Fragment Relative to the Proximal Tibial Fragment at the Osteotomy Site after Open-Wedge High-Tibial Osteotomy.

The present study is aimed at assessing the changes in tibial rotation at the osteotomy site after an open-wedge, high-tibial osteotomy (OWHTO) and analysing the factors that affect rotational changes in the distal tibial fragment relative to the proximal tibial fragment at the same site. This study involved 53 patients (60 knees; 16 males and 37 females) with medial osteoarthritis (OA) who underwent OWHTO and preoperative and 3-month postoperative computed tomography (CT) scans. Rotational angles of the distal tibia were measured using Stryker OrthoMap 3D by comparing preoperative and postoperative CTs. The mean rotational angle yielded an external rotation of 2.9° ± 4.8°. There were 17 knees with internal rotations, 37 knees with external rotations, and one knee with no rotation. The rotational angle significantly correlated with the resultant change in the femorotibial angle (correction angle) and the angle between the ascending and transverse osteotomy lines on the anterior osteotomised surface on which a flange was formed with the distal tibial osteotomised surface (flange angle). The flange angle affected the rotation, but it may have been affected by our surgical technique. The rotational angle did not significantly correlate with the change in the angle of the posterior tibial slope or body mass index. There were significant correlations between the rotational angle and correction angle (r = 0.42, p < 0.05). Additionally, the rotational angle correlated with the flange angle (r = −0.41, p < 0.05).

Effect of longitudinal stiffeners’ spacing in lateral-torsional buckling

This study focused on the experimental assessment of the effect of the spacing between longitudinal stiffeners welded to I-shaped beams under the action of lateral-torsional buckling. In this procedure, 192 aluminum beams on a 1:9 scale were tested under simple-support conditions with a laterally unbraced length ranging from 0.55 m through 1.95 m. Moreover, the stiffeners’ spacing was also ranged from 3 to 9 times the depth of section. The structural behavior of the beams is discussed in terms of their flexural capacity, spacing between longitudinal stiffeners, lateral displacement of compression flange and failure angle twist. Results show that the spacing of longitudinal stiffeners influences the flexural capacity of I-shaped beams, so that, when the spacing of longitudinal stiffeners decreases, flexural capacity tends to increase, especially in the elastic buckling zone.

A framework for train derailment risk analysis

This study aims to develop a framework based on the Nadal formula to assess train derailment risk. Monte Carlo simulation was adopted to develop 10000 sets of random parameters to assess train derailment risk subject to the curvature radius of the track, the difference between the flange angle and the equivalent conicity, and accelerations from 250 to 989.22 gal during horizontal earthquake. The results indicated that railway in Taiwan, China has no derailment risk under normal conditions. However, when earthquakes occur, the derailment risk increases with the unloading factor which is caused by seismic force. The results also show that equivalent conicity increases derailment risk; as a result, equivalent conicity should be listed as one of maintenance priorities. In addition, among all train derailment factors, flange angle, equivalent conicity and unload factors are the most significant ones.

Experimental studies on incremental hole flanging of steel sheets

ABSTRACTIncremental Hole-Flanging (IHF) process has various applications in rapid prototyping and low volume production of conical and vertical flanges in sheet metal parts. Therefore, understanding mechanics and failure strategies in IHF is very important for successful forming without cracks. In this paper, Deep Drawing (DD) steel blanks with pre-cut hole of 40 and 70 mm diameter are used for multistage conical hole flanging. Conical hole flanges are formed on CNC milling machine with starting angle 60° to final angle 90° with an increment of 10°. The experimental results showed a crack at 80° flange angle with the blank of 40 mm pre-cut hole. The blank with 70 mm-pre-cut hole has no such crack behaviour even at 90° flange angle. The paper also discusses the variation of flange height, surface roughness and forming forces in IHF of DD steel sheets.

Numerical Study for Vibration Analysis of Hole Flanged Rectangular Plate

Plates with flange are used in many engineering structures such as aircrafts, ships, and mechanical devices. In this paper, a numerical study for the vibration analysis of fully clamped rectangular Al-1100 alloy plates with different flange angles and different flange inner diameters was worked out. SolidWorks 2014 Simulation add-in was used to perform the analysis. It was found that increasing the flange angle and flange inner diameter increases the fundamental frequency and decreases the flange thickness. Adding the flange can increase the fundamental frequency up to (27%).

On the resistance of a round exhaust hood, shaped by outlines of the vortex zones occurring at its inlet

This paper works toward a goal of determining outlines of vortex zones occurring at the inlet of an exhaust hood and identifying the effect that a hood shape adjusted to these outlines may have on the local drag coefficient of the hood. A mathematical model and a computer program based on the discrete vortex method have been developed for computing velocity fields and boundaries of the first and second vortex zones occurring upon flow separation at inlet of a cone hood. First vortex zone outlines have been found to be geometrically similar even as exhaust hood flange length and angle vary. A computational experiment using the discrete vortex method and computational fluid dynamics techniques, supported by a laboratory experiment, has been carried out to determine the boundaries of the second vortex zone. It has been found that, even though flange length is not a factor for the second vortex zone, the characteristic dimensions of this zone depend on the hood flange tilt angle. Exhaust hood shaping has been assessed for its efficacy in reducing pressure losses at inlet of a circular exhaust hood. The effect of shaping the hood with the outlines of the first and/or second vortex zones has been found in terms of local drag coefficients at hood inlet expressed. Shaping by the outlines of the vortex zones of the most effective exhaust hood with a flange inclination angle of 90° makes it possible to reduce the local resistance coefficient by more than 10 times.