Flange Portion Research Articles

Applicability Verification of Restoration by Welding to Extend the Lifetime of Railway Wheel

Railway wheels, when subjected to wear beyond their designated usage standards due to the operation of railway vehicles, are traditionally managed through a turing maintenance method. This process involves turing the entire worn portion to secure the requisite cross-sectional shape. This approach often leads to disposal after just 2 to 3 turing maintenance cycles. Excessive turing, extending beyond the worn parts, can cause the wheels to fail to meet railway operating specifications. Discarded railway wheels, which contain a high carbon content essential for driving performance, are not repurposed but are instead entirely stockpiled. This research introduces a novel welding restoration technology for railway wheels, targeting the flange portion, a principal area of wear. Utilizing submerged arc welding techniques, this method enables the localized repair of worn parts, minimizing the turing thickness and thus extending the useful life fo railway wheel. To evaluate the on-site applicability and dependability of this welding restoration method, real rail vehicle driving tests were conducted using both conventionally turned and welding-restored railway wheels. Analysis of the wheel profiles substantiated that the welding restoration method delivers mechanical performance comparable to that achieved by traditional turning maintenance.

Effect of Lateral Load on Local Buckling of Latex Wrapped Cold Formed Steel Columns

This paper reports the experimental investigation conducted on unwrapped and latex wrapped cold-formed steel column. Various column cross-sections are subjected to repeated lateral loading till failure. All the columns were observed to fail in local buckling. The column cross-section dimension, provision of interior and exterior lip, and the latex wrapping of the columns influenced the lateral load to failure. Increasing the web length of a column section from 100 to 200 mm increased the load-carrying capacity of the column by 70 to 100 %. The local buckling was initiated in the flange portion of the column. The column section with no lip and interior lip exhibited inward buckling of the flange. The column with exterior lip exhibited outward buckling. The provision of lip and latex wrapping did not influence the initial load-displacement behavior of the columns. However, it increased the load-carrying capacity of the sections. Energy absorption index and ductility factor were calculated and the effect of latex wrapping of the columns on these parameters was evident.

Accuracy of stretch flange formability prediction by considering strain gradient for actual car body parts

The effect of the strain gradient on the stretch flange deformation limit of steel sheets was investigated by hole expansion tests under various forming conditions and by FEM forming simulations. The hole expansion ratio was changed by changing the initial hole diameter and punch shapes. This study clarified the fact that deformation limit strain increases, as it does not depend on the initial hole diameter or punch shape, and thus the strain gradient increases. The deformation limit thickness strain of the stretch flange portion could be changed by changing the strain gradient. These results suggest that the formability of the stretch flange deformation area should be determined from not only the maximum principal strain but also the strain gradient. Then, the accuracy of stretch flange formability prediction by considering the strain gradient for actual car body parts in mass production was investigated. The maximum principal strain and the strain gradient of the parts were calculated by FEM or measured in the press part. These results suggest that the formability of the stretch flange deformation area for actual car body parts could not be predicted by not only the maximum principal strain or the thickness reduction, but also the conventional FLD. This investigation verified the accuracy of stretch flange formability prediction by considering the strain gradient for actual car body parts.

Shear capacity of the cold-formed steel beam to column welded moment connection using clip-angle and flange-cleat

The current research endeavours to evaluate the shear performance of the cold-formed steel (CFS) welded moment connection between beam-to-column with 36 laboratory tests. The web portions of the beam and column were connected by CFS welded clip-angle to form a CFS welded shear connection. Subsequently, it is converted into a welded moment connection by including a flange cleat between the flange portions. The shear capacity of the welded shear connection increases by an average of 67% after the inclusion of flange cleats, which is quantified using a performance ratio variable. This research presents two shear equations for the CFS welded moment connection (i) a new empirical shear equation; (ii) a new shear equation representing the shear strength of the moment connection as a function of the shear strength of the shear connection. The variability of the shear performance of welded moment and welded shear connections is expressed with force versus displacement plots and failure modes of the clip angles. The failure modes observed in the clip-angle in both welded moment and welded shear connections are (i) Local buckling and (ii) Distortional buckling. The shift in failure modes of some of the clip-angle in the WM connection (Local buckling) and the WS connection (Distortional buckling) indicates the effectiveness of flange-cleat in resisting due to free twisting of the beam because of load offset from the shear center. The design factors were also determined for the LRFD, LSD, and ASD methods by performing reliability studies.

Effects of processes parameters on spring back, wrinkles and cracks in different flanging processes: A Review

Flanging is an important type of sheet metal bending process. In present review, an effort was made to explore the contributions of various researchers to drawn out the cause of defects in the flanging process. Several parameters such as geometrical, material and process parameters affect the formability of the flanging process. In straight flanging process, spring back (due to elastic recovery) is a major problem that affects dimensional and geometrical accuracy of a bent component. Several factors are responsible for springback such as – profile radius of punch and die, bend angle, thickness of sheet, clearance between punch and die, blank-holder force, Young’s modulus, n-value, yield stress, plastic anisotropy of materials, velocity of punch etc. In shrink flanging process, wrinkling is the prime concern that occurs due to the excessive compressive stress in the flange portion. It is mostly affected by mechanical properties of material (R-value, n–value etc.), geometry of the tools and blank, process parameters. In stretch flanging process, the effect of material parameters is found to be less as compared to geometrical parameters for crack initiation and thinning.

Development of multi-layered sewer pipe plug — 1st report: Ruptured test and stress analysis of protective sheet

In recent years, the sewer system in Japan is becoming obsolete. It is, therefore, necessary to reinforce or repair without stopping sewer functions by applying a suitable water stopping method. In this study, a multi-layered sewer pipe plug consisting of a protective sheet and inner and outer rubber balls is focused since it can be installed and removed at the construction site in a short time conveniently. This sewer pipe plug has several advantages dealing with various diameters compared to the conventional type. In this study, the rupture test is conducted to improve the water stopping performance. The fractured position of the protective sheet of the sewer pipe plug is investigated experimentally. It is clarified that the maximum stress around the flange portion can be reduced by decreasing the flange inner diameter.

Behaviour of thin-walled intermediate stiffened back-to-back columns under axial compression

The axial load carrying abilities and the buckling behaviour of Cold-Formed Steel (CFS) Stiffened Built-up Columns (SBC) has been presented in this paper. In total, the results from 8 actual experiments and 64 finite element models in the parametric studies on CFS back-to-back channels built-up screw fastened SBCs with different cross-sections are reported. The specimens were tested with fixed end condition under axial compression. Sections with lip and web stiffeners predominantly failed due to distortional buckling mode whereas all the other sections failed due local or global flexural buckling mode or interaction of local and global modes of failure. The inclusion of intermediate stiffeners and global stiffeners supported in resisting buckling. The results obtained from this study were compared with the estimated load carrying capacities using Direct Strength Method (DSM) design equations. It was found that for built-up SBC members the method of calculating its compression capacity was over-conservative. SBC sections made of lipped channels along with longitudinal stiffeners exhibited highest load carrying ability. Providing stiffeners at the junction of flange and web portions did not radically increase in load carrying ability when compared to sections having stiffeners in the webs and lip portions. SBC sections made of lipped channels also failed in similar buckling phenomenon like in other sections but the plate element local buckling predominantly occurred at the lip portions.

Effect of process parameters on micro flexible deep drawing of stainless steel 304 cups utilizing floating ring: Simulation and experiments

Due to its simplicity, versatility of process and feasibility of prototyping, using flexible tools in sheet forming seems appropriate for producing cups at microscales. This article presents a novel micro deep drawing technique in which a cooperation of a floating ring, as a primary rigid die, with a rubber pad, as a main flexible die, is employed for forming micro-cups. The function of the floating ring is to overcome minor wrinkles that commonly occur at flange portion, while the flexible die is to complete the forming stroke. The influence of initial sheet thickness, drawing ratio, punch corner radius and rubber height is studied through simulations and experiments. Furthermore, three size scales are adopted to investigate the possibility of using the proposed technique under different process dimensions. The code ABAQUS/Standard is utilized to build the finite element models and thereafter micro-forming experiments are carried out to verify the numerical results. For this purpose, a special setup is developed to be compatible with simulation models. The results show that the formed cups are characterized by very accurate dimensions, high surface quality, homogeneous wall thickness distribution in terms of maximum thinning and thickening and relatively large aspect ratio.

Flexural Strengthening of RC Continuous T-Beams Using CFRP

In this paper, experimental investigations for strengthening reinforced concrete (RC) continuous beams were performed. Eighteen T-beams were cast, twelve of which were inverted T-beams where the flange portion of the T-beam was subjected to positive flexure to represent the support region of a continuous beam. Six of the T-beams were non-inverted where the web is subjected to positive flexure. Carbon fiber reinforced polymer (CFRP) sheets with different widths were considered, and different strengthening configurations with the same area of CFRP were investigated. The use of one-layer, multiple layers, or multiple strips of CFRP were evaluated to investigate the effect of these configurations on the ultimate capacity and ductility of the strengthened beams. From the experimental observation of the non-inverted beams, it was found that the ultimate load capacities of the CFRP-strengthened beams were enhanced by 4% to 90% compared to the control beam. Using multiple layers of CFRP sheets enhanced the stiffness of the beams by 4% to 46%, depending on the CFRP area and configurations. The debonding of CFRP before the ultimate failure provided additional ductility to the tested beams. For the strengthening of the inverted beams, it was found that the addition of CFRP strips did not increase the strength of the beams when the width of CFRP to beam width ratio was less than 0.25, but the ductility of the beam was enhanced slightly. The use of multiple strips was found to be a more effective way for the strengthening of the negative moment region than using multiple layers. This can also provide more desirable modes of failure than when applying CFRP in multiple layers. Ductility was found to be lower if multiple layers were used compared to other configurations. Moreover, it was observed that as the compressive strength of concrete increased the addition of the CFRP improved the beams ductility.

Removal of Aluminosilicate Bond and Process Optimization on Recovery of Sol Gel Alumina Abrasive Grain from Abrasive Industry Waste

Sol-gel alumina abrasive grains are used in high cutting speed and high material removal process. The need of sol gel alumina abrasive grain is huge. So, the waste generated from the grinding process is also high. In grinding operation, flange portion of the grinding wheel is unused and dumped as waste. Recovery of abrasive grains from this unspent portion adds wealth. This study deals with recovery and re-use of sol gel alumina abrasive grains. Chemical method is opted to recover the sol gel abrasive grains. Based on previous studies, the process parameter such as solid liquid ratio, lump size, immersion time and stirring speed were selected as the control factors and extraction efficiency of sol gel alumina abrasive is considered as response parameter. The experimental results show that major influencing control factor sequence were lump size> solid liquid ratio > stirring speed and > immersion time. The optimal combination for the maximum sol gel alumina grain recovery will be smaller lump size, maximum solid liquid ratio, maximum stirring speed and intermediate immersion time. Apart from that, the surface features of the recovered abrasive grains are studied by scanning electron microscopy. The elements during chemical washing process are observed using energy-dispersive spectroscopy (EDS). Recovered grains from this process can also be reused in the grinding wheel production. This is the feasible and economical method for recovering the sol gel alumina grains from the spent grinding wheel waste.

Buckling Behavior of Schifflerized Angle Sections

Triangular-based communication towers result in significant weight reduction compared to conventional square-based towers. Hot-rolled 90° steel equal angle sections with bent-up gusset plates are used for triangular towers, since 60° angles are not readily available in India. In triangular towers, the included angle between two flanges of the main leg member shall be 60° for smooth connection between leg and bracing members. The required included angle of 60° between the two flanges of a leg member can be achieved by “schifflerizing” the hot-rolled 90° angles. Numerical models were developed for the three different schifflerized angle sections 90 × 90 × 6 mm, 100 × 100 × 8 mm and 130 × 130 × 10 mm using general purpose finite element software NE-Nastran and calibrated with the test failure modes. Using this as base model, parametric studies are conducted on the same three angle sections by varying the lengths from 500 to 2500 mm. The compression capacities of these angles are predicted using the analytical methods given in the literature and compared with the parametric study and the available test results. For schifflerized angle sections, the warping constant is maximum when 90° and 60° flange portions are equal. The study result shows that schifflerized angle sections with width-to-thickness ratio ‘w/t’ below 13 are governed by torsional–flexural buckling up to slenderness ratio 70 and the sections with ‘w/t’ ratio above 15 are governed by flexural buckling.

Member distortional buckling behaviour of hybrid double-I-box beams

This paper compiles the experimental and finite-element parametric study on member distortional buckling behaviour of new built-up metal hybrid double-I-box beams (HDIBBs). The cross-section of this built-up beam is unique and looks similar to the shape of a double-I-box fabricated using four channel sections. The flange plates were provided with an intermediate stiffener. In these built-up beams there is more material in the flange portions far away from the horizontal centroidal axis of their cross-section. Hence, there is an increase in the flexural rigidity that enhances the moment capacity of the beam, under major axis bending. The geometry consists of torsionally rigid closed-box web portion that provides high resistance to minor axis lateral-buckling. The varying parameters considered were the ratio of yield stresses of the flange to the web steel plates, the ratio of breadth to the depth of the section, and the flange plate thickness. In the experimental programme, all the HDIBB members failed due to kinds of distortional buckling which was identified by web buckling and flange twist along edges. The results revealed that when flange plate slenderness increases there is a drop in the moment resistance capacity of the beams. The numerical study was performed using ABAQUS software. In comparison, there was good agreement between experimental and numerical results. The validated finite element models were further extended to perform parametric studies on ideal HDIBB models. Both the experimental and parametric study results were compared with the predicted strengths using effective width method equations specified in the Euro code standards EN 3-1-3. It was found that the current Euro code design rules slightly over-estimate the distortional buckling resistance capacity of closed form built-up cold-formed steel members. A new design equation was formulated and recommended for estimating the reduction in distortional buckling moment resistance capacity for HDIBBs.

Prediction of railway wheel wear and its influence on the vehicle dynamics in a specific operating sector of Indian railways network

In railway operations, wear prediction due to wheel-rail interaction is crucial for different aspects such as running stability, passenger safety and comfort, life cycle optimization and maintenance scheduling. In this article, wheel wear is estimated through co-simulation between multi-body vehicle dynamic model developed in Adams™ VI-Rail™ software and wear evolution model developed in MATLAB® software. Semi-Hertzian/STRIPES approach and modified Kalker's FASTSIM approach are used for calculating normal and tangential stresses, respectively. The contact patch obtained from dynamic analysis is discretized into strips and variations of contact angle and spin for each strip, although small, are taken into account. Archard's wear formulation is applied for each strip within the contact patch. The wheel profiles are smoothened and are updated at intervals for further dynamic analysis. This way, the outputs from dynamic analysis (contact patches, creep forces, etc.) are input to the wear evolution model and the outputs from the wear evolution model (worn wheel profiles) are fed to the dynamic analysis. The wear at the flange and tread portions of the wheels during the normal service condition in an operational track sector between two major rail stations in India, containing curved and straight portions, speed variation (acceleration and braking), and corresponding track configurations (super-elevation, irregularities, etc.) are estimated and the wheel re-profiling schedule was obtained. In addition, the influences of the various stages of wheel wear on the dynamic responses such as curving performance, critical speed and ride comfort of the railway vehicle on the simulated test track are evaluated to justify the maintenance/wheel re-profiling schedule.

Investigation of Caulking

Research works on the joining of shaft and plate are summarized and the features of the conventional caulking process are discussed. Maximum caulking force is limited by the occurrence of shaft buckling and plate warping. The joining force in upset caulking mainly results from press fit force between the hole wall of the plate and the enlarged shaft diameter, while the joining force in shear caulking mainly results from press fit force at the flange portion of the caulked head. To improve joint efficiency, a two-step process in which upset caulking is combined with shear caulking, is newly proposed. Optimum working conditions are examined and experimental results show considerable improvement of joining efficiency, especially in rotational resistance. Some ideas for the practical application of this process are proposed here.

Effect of strain gradient on stretch flange deformation limit of steel sheets

The effect of strain gradient on the stretch flange deformation limit of steel sheets was investigated by hole expansion test under some forming conditions and by FEM. Hole expansion ratio was changed by changing initial hole diameter and punch shapes. It was clarified that a limit stretch flange deformation strain basically depends on not the initial hole diameter and the punch shape by themselves but the strain gradient in the radial direction. The strain gradient along the direction toward the maximum principal strain did not affect limit deformation strain. The limit deformation thickness strain of the stretch flange portion could be changed by changing strain gradient. These results suggest that the formability of stretch flange deformation area should be determined from not only the maximum principle strain but also the strain gradient and blanking clearance.

Manufacturing of Axisymmetric Components out of Superalloys and Hard-to-Deform Steels by Roll Forming

Heat-resistant alloys are the basic material of gas turbine engine (GTE) design. Fine-grained structure in these alloys can be formed by isothermal forging and then different axisymmetric GTE components as wheels, shafts, rings can be superplastic roll formed. Examples of the superplastic and isothermal deformation use for manufacturing components out of superalloys and steels for critical applications are given. The possibility of roll forming parts as rings with a diameter up to 800 mm and as flange - cone with a diameter up to 600 mm out of superalloys (Inconel 718, EK79, EP741NP), accordingly, on SRZHD-800 and modified PNC-600 mills were showed. The macrostructure investigations of the components after the roll forming showed that the homogeneous structure was formed. The microstructure at the flange portion was fine-grained and at membrane zone was coarse-grained. Cone part was roll formed at isothermal condition from pre-stamped chromium martensitic steel sheet. Manufacturing technology of roll forming was tested by computer and physical simulation. Service properties of components were obtained by subsequent heat treatment. The effectiveness of the technology associated with increased service properties of components and decreases the labor content by automated equipment.

Residual stress of 800 MPa high strength steel welded T section: Experimental study

An experimental study is presented to investigate the residual stress in 800MPa high strength steel welded T sections using the sectioning method. A total of four different sections with 7mm thickness steel plates are tested to quantify the magnitude and distribution of both compressive and tensile residual stress. The effect of the width-thickness ratio of web and flange on the distribution of the residual stress is established. The results show the residual stress in all sections is in self-equilibrium. The maximum tensile residual stress locates in the central portion of flange, while the minimum tensile residual stress distributes on both ends of web and flame cutting edges of flange. The maximum tensile residual stress, ranging from 0.43fy to 0.68fy, has no obvious relations with the width-thickness ratio of plate. The constant compressive residual stress distributes in the central portion of projecting flange and web. The maximum compressive residual stress, ranging from 0.09fy to 0.46fy, decreases as the width-thickness ratio of plate increases, while the area of stress distribution zone increases as the width-thickness ratio of plate increases. A simplified model is suggested for analysis and design based on the magnitude and distribution of residual stress.

Metallurgical Analysis on a Cracked Super Duplex Stainless Steel Flange

A flange-to-pipe weldment in a seawater-intake-return-line suffered from cracking on its flange portion after in service for 4 months. The flange was fabricated from S32750 super duplex stainless steel. The cracked flange was investigated by visual inspection and fractographic examination on the crack surface, metallographic examination, hardness measurement, and chemical composition analysis of the flange-to-pipe weldment. The results of laboratory analysis showed that the flange had cracked in a brittle manner resulting from the presence of large amount of sigma phase in the flange material. Formation of such brittle second phase precipitates in the flange material was due to improper heat treatment.

Behaviour of normal and high-strength castellated steel beams

This paper investigates the design and behaviour of normal- and high-strength castellated steel beams under distortional buckling. An efficient non-linear three-dimensional finite-element model has been developed for the analysis of the beams. The initial geometric imperfection, residual stresses and material non-linearities of flange and web portions of the steel beam sections were incorporated in the model. The non-linear finite-element model was verified against tests on castellated beams having different lengths and different cross-sections. An extensive parametric study was carried out to study the effects of the change in cross-section geometries, beam length, steel strength and lateral buckling restraints on the strength and distortional buckling behaviour of castellated steel beams. The study has shown that the use of high-strength steel offers a considerable increase in the failure loads of castellated beams, which has not been addressed to date in the literature. The failure loads predicted from the finite-element model were compared with that predicted from Australian Standards for steel beams under lateral buckling. It is shown that the Specification predictions are generally conservative for normal-strength castellated steel beams and quite conservative for high-strength castellated steel beams. Hence, a design equation was proposed for high-strength castellated steel beams.

八分割しわ抑え板を用いたアルミニウム板の摩擦援用角筒深絞り加工

Friction aided deep drawing has been investigated to confirm the possibility of the deep drawing of square cups. A blank holder is divided into eight segments and these segments are used instead of the conventional blank holder. These segments of the blank holder can move radically inwards and outwards depending on the blank holding pressure. When an axially punch is used together with this deep drawing process, the drawing force decreases and also the shape and dimensional accuracy can be improved. In the square deep drawing, the deformation aspect varies from portion to portion; at the punch corner and at the straight flange portion. Experimental results show that the metal flow at the corner and at the straight f1ange portion is approximately uniform. The square cups of 60 mm height, which is 2.3 times of the side length, can be obtained from a circular blank of 120 mm diameter and 0.5 mm thickness. The number of moment of radial direction of the blank holding segments was 44 times.