Flange Part Research Articles

Experimental and numerical study of residual stress distribution of corrugated web I-beams

An appropriate evaluation of residual stress is of great importance for the structural performance of corrugated web I-beams under monotonic and cyclic fatigue loading. An experimental programme is presented to examine the residual stress distribution of corrugated web I-beam sections using hole-drilling method. It was found that, unlike flat web I-beam sections, the residual stresses on the beam flange are varied from the location with longitudinal fold to that with the inclined fold of the corrugated web. The results of validated finite element models demonstrate that the distribution of maximum residual tension stress is notably affected by its location on the flange related to corrugation. Moreover, the maximum residual stress is reduced with wider distributing range with the increase of the corrugation angle and curvature radius, especially for the flange part. A residual stress distribution model allowing for above mentioned influencing parameters was proposed and validated against test results, thus demonstrating an improvement of referred analytical models.

A Development of Magnetic-wheeled Robot with High Loading Capacity and Ability to Travel through plate to plate and Flange Parts

A Development of Magnetic-wheeled Robot with High Loading Capacity and Ability to Travel through plate to plate and Flange Parts

Numerical modeling and prediction of adhesion failure of adhesively bonded composite T-Joint structure

This study is reported the adhesion failure in adhesive bonded composite and specifically for the T-joint structure. Three-dimensional finite element analysis has been performed using a commercial tool and the necessary outcomes are obtained via an eight noded solid element (Solid 185-element) from the library of ANSYS. The structural analysis input has been incurred through ANSYS parametric design language (APDL) code. The normal and shear stress distributions along different layers of the joint structure have been evaluated as the final outcomes. Based on the stress distributions, failure location in the composite joint structure has been identified by using the Tsai-Wu stress failure criterion. It has been found that the failure index is maximum at the interface between flange and web part of the joint (top layer) which indicates the probable location of failure initiation. This kind of failures are considered as adhesion failure and the failure propagation is governed by strain energy release rate (SERR) of fracture mechanics. The different adhesion failure lengths are also considered at the failure location to calculate the SERR values i.e. mode I fracture (opening), mode II fracture (sliding) and mode III fracture (tearing) along the failure front. Also, virtual crack closure technique (VCCT) principle of fracture mechanics steps is used to calculate the above said SERRs. It is found that the mode I SERR is more dominating compared to other two modes of failure for the joint considered. Finally, the influences of various parametric (geometrical and material) effect on SERR of the joint structure are evaluated and discussed in details.

송수관 유동 및 피로해석

In theory, the maximum allowable working pressure of cast iron, with flange specification PN10 and pressure rating KS B1501, is 1.0 ㎫. However, in reality, the maximum allowable pressure can be 1.3 ㎫ if the strength of the materials used and the stability of the bolted joints are considered. The stability of the flange part of a cast iron pipe was confirmed using function test analysis SPS-KWWA-D111. Next, a D900 (denotes pipe diameter) water pipe was modeled based on the combination of a steel pipe and gray cast iron pipe. Subsequently, the streamline, flow velocity, and pressure distribution, when the valve opened and closed based on the general pipe flow rate and discharge pressure, were calculated. Finally, fatigue analysis was performed using the pressure data for the pipeline, to confirm stability.

Parametric modeling at defining technological axisymmetric flanging parameters from sheet blanks

The object of the research of the presented article is the internal axisymmetric cylindrical flanging. This work is intended to improve the quality and accelerate the development of technology for flanging round holes from sheet blanks and designing tooling by improving the accuracy of calculating the diameter of the flanging holes in the automated mode for constructing three-dimensional models of a blank and a flanged product. Formulas are proposed that increase the accuracy of calculating the diameter of the hole for flanging. The accuracy of calculating the diameter of the flange hole according to the proposed formulas is determined by comparing the mass of the workpiece with the mass of the flanged part. The algorithm for the automated construction of a sketch of a flanged part and the determination of technological parameters is implemented in KOMPAS-3D. The constructed models allow making changes to their parameters and to provide automatic presentation of the calculation results, as well as their correct graphical interpretation. A discussion of the results of the work allows drawing conclusions about the correctness of the proposed mathematical model and its applicability to the automated construction of three-dimensional models of flanged parts, which will simplify the development of technological and design documentation with a simultaneous increase in their accuracy and reduce the cost of preparing the production.

Hot Axial Rotary Forging of Flanges Standard EN 1092

The paper considers the technology of manufacturing flange parts using local methods of metal forming. Various technologies of manufacturing of ring blanks for the subsequent rotary forging of flanges are offered and investigated. On the basis of computer simulation, the main dimensions of the workpiece have been chosen, providing the best forming parts and the parameters of the technology mode. The results of experimental studies have shown that this technology is possible to manufacture flanges according to EN 1092 using the process of axial rotary forging with cylindrical rolls. The use of local methods of deformation of metals allows expanding the possibilities of technological processes at lower power equipment.

Cold Rotary Forging of Inconel 718

The present work includes an in-depth study of microstructure and mechanical property development in a cold rotary forged component manufactured from Inconel 718 alloy. This work is pioneering in that there is no detailed study available in the literature focussing on cold rotary forging of Inconel 718. A tubular preform of 6 mm wall thickness was cold rotary forged into a 90 degree flange part followed by annealing with double aging. The present study provides a thorough analysis of microstructure, hardness and surface roughness evolution from as-received to final cold rotary forged and heat-treated condition including crystallographic texture changes occurring at different stages. The solution-annealed condition of the preform was found to be most suitable for cold rotary forging of Inconel 718. An annealing treatment followed by double-aging imparted desired properties such as homogeneous microstructure, uniform hardness distribution and improved surface roughness into the cold rotary forged Inconel 718 flange. The cold rotary forging can be a cost-effective route for manufacture of axisymmetric components with high material yield and low buy-to-fly ratio for expensive materials such as Inconel 718.

Joining Strategy Analysis of Structural Dynamic in Top Hat Plate of Dissimilar Materials

Structural dynamic can be described as a study regarding analysis of model under exertion of dynamic loading. Joining in structure such as riveting, welding and soldering were strongly effects the structural dynamic properties. The aim of this paper is to conduct various joining strategy analysis in finite element software by using top hat plate structure in car as a model and result is compared with experimental data. Normal mode analysis with free-free boundary condition is applied. Resistance spot welding (RSW) technique is selected to weld flange part in top hat plate between dissimilar materials which is mild steel 1010 and stainless steel 304 with specified parameters applied. Modal testing via impact hammer test is carried out at the welded top hat plate for experimental analysis purpose. Correlation in between FEA and EMA results need to be conducted. By selecting identified parameters to execute model updating on the structure using sensitivity analysis method, the discrepancies in natural frequencies were reduced between FEA and EMA. CWELD element was chosen to represent weld model for spot weld joints due to its accurate prediction of frequencies and mode shapes compare to other weld modelling. As a closure, connection in structure parts play significant role in structural dynamics and model updating is one of successful method to lessen the discrepancies between FEA and EMA.

Optimal Design of Constructal T-Shaped Fin Under Partially Wet Condition for Enhanced Thermal Performance: An Analytical Approach

In refrigeration and air conditioning systems, the fin surface may become dry, fully wet or partially wet depending upon the psychometric, thermo-physical and geometric parameters. The current work is intended to determine the length of the dry portion, temperature distribution, performance and optimum design parameters of a T-shaped fin under partially wet condition. Temperature dependent thermal conductivity of the fin material is taken and the humidity ratio of saturated air is considered to vary linearly with the corresponding fin surface temperature. Considering these the governing equation of T-shaped fin becomes nonlinear and it has been solved analytically by using Homotopy Perturbation Method. The point of separation between the dry and wet portions of a T-shaped fin may be located either in the stem or flange part and hence, two cases having different governing equations and boundary conditions are analyzed in the current study. For the optimization study, Lagrange multiplier technique is employed and the results are obtained by maximizing the heat transfer rate for a constant fin volume. Further, a comparative study is presented between insulated and convective fin tip conditions.

Theoretical prediction and crashworthiness optimization of thin-walled structures with single-box multi-cell section under three-point bending loading

This paper aims to study the bending collapse behavior and energy absorption mechanism of thin-walled structures with single-box multi-cell section (TWS-SMC). A theoretical prediction model of TWS-SMC is developed under three-point bending loading. The theoretical prediction formulas are also derived by dividing the TWS-SMC into web parts and flange parts. The accuracy and generality of the theoretical prediction formulas are validated by performing three-point bending test and finite element analysis (FEA). To further validate the theoretical prediction formulas and improve the energy-absorption capacity, both theoretical prediction formulas and FEA based surrogate models are employed to perform the crashworthiness optimization of the TWS-SMC. The results show that (i) the Pareto frontiers obtained from the theoretical prediction formulas show an excellent coincidence with those from the FEA based surrogate models, which means that the theoretical prediction formulas can be directly used to crashworthiness optimization design for the sake of computational efficiency; (ii) the energy-absorption capacity of TWS-SMC is superior to thin-walled structures with single-box one-cell section (TWS-S1C) under the same weight, and its energy-absorption capacity will improve gradually with the number of web parts increased.

Study on size effect affected progressive microforming of conical flanged parts directly using sheet metals

Progressive forming of microparts directly using sheet metals is an efficient approach for realization of mass production. However, there are many unknown behaviors and phenomena affecting the decision-making in process and tooling design, because the specimen generally comprises only a few grains in the wall thickness, where the mechanical response and deformation of material behave differently compared with those in macro-scale due to size effects. In this research, a progressive forming system including punching, extrusion, and blanking operations with three-scaled punches and dies was developed to fabricate cylindrical parts and conical flanged parts by directly using copper sheets with different grain sizes. Through physical experiments, measurement and analysis of the deformations and related variables, grain and specimen size effects affected deformation behaviors and the characteristics of the conical flanged parts were comprehensively studied in term of forming pressure, microstructural evolution, dimensional accuracy, undesirable geometries and surface qualities. It is revealed from the experimental results that the forming pressure increases with the decrease of specimen and grain size. For the cylindrical parts, their scaled length increases with the decrease of grain size and increase of scaling factor. For the conical flanged parts, four deformation zones were divided based on microstructural evolution and a worse forming quality appeared on the conical surface, where the defects including microcracks, microbulges, and micropits were observed. Properly coarse grains can reduce the undesirable geometries, but at a slight cost of deterioration of the quality of the formed conical surface. When scaled down to micro-scale, the undesirable geometries and the surface qualities deteriorate considerably. The anisotropy of individual grain is not significant on the constrained features and surfaces. All these understandings facilitate the fabrication of conical flanged microparts directly using sheet metal in the aspects of deformation behaviors and controlling product qualities and enrich the knowledge of this unique microforming process.

Flange forming at an arbitrary tube location through upsetting with a controllable deformation zone

Instability is the most common challenge faced in the production of tubular flanged parts, which is usually limited by dimensional parameters, such as the slenderness ratio of height to thickness and the ratio of initial tube thickness to final flange thickness. To extend the formability limit in a single step, an alternative forming method called upsetting with a controllable deformation zone (U-CDZ) is proposed in this paper. In the proposed method, the workpiece is pushed from the holding cavity of a die into the forming cavity. Under an appropriate counter force, a stabilized deformation zone is established, which eliminates the limitation of the initial slenderness ratio in the conventional upsetting method. Detailed analyses of the forming qualities and forming load were performed. Due to the employment of the location zone, the tube flange could be formed at an arbitrary location (at the end of tube or away from the ends) without defects. The feasibility of the U-CDZ method was validated through finite element modelling and metal experiments on aluminium.

Shape Defects in The Flexible Roll Forming of Automotive Parts

Flexible roll forming allows variable cross sections of profiles to be made by using adaptive roll stands. The most common shape defects that occur during flexible roll forming are edge wave and longitudinal bow. These two defects are necessary to consider together for relatively thin-walled blanks because they usually occur simultaneously during flexible roll forming. To understand the occurrence of these defects, finite element (FE) simulations based on the rigid shell concept were carried out using three blanks with different shapes: trapezoid, concave, and convex. The FE analysis on the flexible roll forming process was performed first, and then the gap of rigid shell has been decreased for reducing the longitudinal bow in roll formed blank. The reduction of longitudinal bow in the web part usually causes edge wave in the flange part. The occurrence of shape defects is investigated based on the relationships among edge curvature, longitudinal stress at the edge, and longitudinal bow height. When longitudinal bow is reduced, the longitudinal stress at the edge of roll formed blank is changed from tensile to compressive in convex blank but in concave blank, tensile residual stress increases. Edge waves occur in the flanges of trapezoid and convex blanks as a result of decreased longitudinal bow. Lab-scale flexible roll forming experiments show multi-stand forming with a leveling roll is desirable to reduce both edge wave and longitudinal bow.

Forward and inverse nonlinear heat transfer analysis for optimization of a constructal T-shape fin under dry and wet conditions

This work deals with direct and inverse analysis of T-shaped dry and wet fins. Direct analysis is done to study heat transfer performance, whereas inverse analysis is performed to simultaneously estimate five optimum geometric parameters satisfying a prescribed fin volume. The modified differential evolution (MDE) search algorithm is used to explore the required geometrical parameters pertaining to the stem and the flange parts of the fin. In the present MDE, the mutant is generated using five distinct vectors instead of three as conventionally practiced. Due to the existence of multiple solutions, the selection criterion is based upon the fulfilment of different performance parameters. These involve individual maximization of heat transfer rate, fin efficiency and fin effectiveness. Since the application of the differential transformation method (DTM) is not yet demonstrated for nonlinear heat transfer analysis of T-shaped wet fins, thus, for generating the heat transfer parameters using the inversely estimated geometric parameters, a forward approach based on the DTM is used here. Parametric variations along with necessary validations of the direct method are presented. Furthermore, a comparison of the present MDE search-based inverse algorithm is done with a classical gradient-based optimization technique. It can be highlighted from the present study that only when at-least three geometrical parameters are known, then the classical method successfully yields heat transfer performance parameters comparable with the MDE algorithm. From the optimization study, it is found that a particular value of fin performance (heat transfer rate, efficiency, effectiveness) can be acquired with various values of surface area and even at a given surface area, different fin performances can be obtained. However, a single and distinct operating point is revealed where the performance index of the fin is maximized. For ensuring maximum possible performance from constructal T-shape wet fins, it is recommended that for the present type of problem, the present stochastic optimization method such as MDE must be used where the classical deterministic methods suffer from inherent limitations on multi-variables optimization.

Experimental and Analytical Study on Torsional Behaviour Of RC Flanged Beams Strengthened With Glass FRP

Environmental degradation, increased service loads, reduced capacity due to aging, degradation owing to poor construction materials and workmanships and conditional need for seismic retrofitting have demanded the necessity for repair and rehabilitation of existing structures. Fibre reinforced polymers has been used successfully in many such applications for reasons like low weight, high strength and durability. Many previous research works on torsional strengthening were focused on solid rectangular RC beams with different strip layouts and different types of fibres. Various analytical models were developed to predict torsional behavior of strengthened rectangular beams and successfully used for validation of the experimental works. But literature on torsional strengthening of RC T- beam is limited. In the present work experimental study was conducted in order to have a better understanding the behavior of torsional strengthening of solid RC flanged T-beams. An RC T-beam is analyzed and designed for torsion like an RC rectangular beam; the effect of concrete on flange is neglected by codes. In the present study effect of flange part in resisting torsion is studied by changing flange width of controlled beams_ The other parameters studied are strengthening configurations and fiber orientations. The objective of present study is to evaluate the effectiveness of the use of epoxy-bonded GFRP fabrics as external transverse reinforced to reinforced concrete beams with flanged cross sections (T-beam) subjected to torsion. Torsional results from strengthened beams are compared with the experimental result of the control beams without FRP application. The study shows remarkable improvement in torsional behavior of all the GFRP strengthen beams. The experimentally obtained results are validated with analytical model presented by A.Deifalla and A. Ghobarah and found in good agreement.

An Intelligent Method to Design Die Profile for Rubber Forming of Complex Curved Flange Part

Rubber forming is an important forming process for the manufacture of aircraft sheet metal parts. The springback is one of the main defects in rubber forming. Classical springback compensation by displacement adjustment method using finite simulation is not satisfactory. In this research, the algorithms of compensating the arc and flange surface of complex curved flange with correction formula are proposed by experiment. The correction formula was developed based on the CATIA V5 R19 using Component Application Architecture. Compensate profile is presented including surface pick up, line pick up, division, compensation, extending, and trimming. The die profile of part with complex curved flanges in aircraft could be designed rapidly. It was found that the forming pressure has a little effect on the springback. This is within the tolerance limits of the part. The results reveal the method can achieve the industrial part precisely. The method is demonstrated on an aircraft wing rib part.

Study of the nature and causes of damage of 40KhN2MA steel propshafts

The nature and character of the destruction of the high-loaded airscrew shaft of the gas turbine engine made of steel 40KhN2MA are studied using the methods of scanning electron and optical microscopy and X-ray spectral microanalysis. We determined the chemical composition, microstructure and character of destruction of the flange part of the shaft. It is shown that chemical composition of the shaft material meets the requirements of the regulatory documents and defects of metallurgical origin are absent both in the metal of the shaft and in the fatigue fractures. All the identified cracks have been formed during operation, and developed according to the fatigue mechanism. Zones of fretting-wear and fretting-corrosion damage to the surface in the stud holes are the foci of the fatigue crack birth in the airscrew shaft. The cause of formation and development of the fatigue cracks in the shaft flange is a high level of contact stresses in the flange body, attribute to a poor quality of the interface of the splined joint due to significant fretting corrosion damage to the splines and vibration damages. A set of recommendations and measures aimed at elimination of the adverse factors is elaborated. To exclude the formation and development of fatigue cracks in the splined flange upon operation, we recommend to: optimize the tightening torque of the splined joint; introduce quality control of the interface between contact surfaces of the splined joint when replacing the airscrews; address the issue of dynamic balancing of the airscrews upon their production and repair.

A digital technique for fabricating an interim implant-supported fixed prosthesis immediately after implant placement in patients with complete edentulism

The conversion of a denture into an interim implant-supported, screw-retained restoration has become the standard method for immediate interim restoration in patients with complete edentulism. The most critical steps of the denture conversion process are the creation of appropriate denture access holes to prevent displacement of the denture by the interim cylinders and removal of the denture flanges to facilitate both good esthetics and accessibility for oral hygiene after the denture is connected to the interim cylinders. This article presents a digital technique for designing and fabricating an interim implant-supported, fixed prosthesis for edentulous patients. The interim prosthesis has cylinder access holes that are digitally prefabricated and a denture flange part that is designed to be easily sectioned. This technique facilitates more straightforward and efficient immediate restoration for edentulous patients after implant placement.

Response of shape optimization of thin-walled curved beam and rib formation from unstable structure growth in optimization

A thin-walled curved beam is a complex structure. Sectional deformation occurs due to induced out-of-plane force when the beam is bent. Bending stiffness is significantly lowered due to this deformation. Installation of ribs to support this induced force is often an effective countermeasure to ensure stiffness. This study examined shape optimization of an I-sectional curved beam. Ribbed structures were successfully created from non-ribbed structures by adding humps to the initial structure. It was discovered that instability of the shape optimization occurs under the influence of the induced force. Here, ‘instability’ refers to the amplification of initial perturbations similar to buckling phenomena. In the present case, the humps grew and formed ribbed structures. The bending stiffness of the ribs was significantly improved. In addition, simple thickening of flange parts also effectively improves the bending stiffness. As these two structural improvements progress simultaneously, branching of the optimization occur. This branching depends on the given volume constraint. A parameter study targeting volume observed branching to ribbed or thickened non-ribbed structures. This instability enables a leap from a non-ribbed to a ribbed structure in the optimization.

Life extension of Structural Repairs – A statistical approach towards efficiency improvement

The life extension program of aircraft is taken up whenever aircraft’s intended life reaches close to its DSG (Design Service Goal). The Extended Service Goal (ESG) of an aircraft, in general, and structural repairs, in particular, is arrived at on the basis of F&DT (Fatigue & Damage Tolerance) analysis. Life extension program of aircraft consists of assessment of remaining life of all parts of the aircrafts including structural, mechanical, and electrical and avionics equipment and structural repairs. For life extension of stringer repair, as an example, it is required to re-assess the fatigue life of stringer in the presence of coupling under modified load spectrum. This is achieved by assessing the fatigue life of Web and Outer Flange (OF) part of stringers separately as per F&DT justification philosophy. Assessment of the fatigue life requires determination of stress concentration factor (Kt) for different combination of width, pitch, stringer thickness, coupling thickness and pad-up thickness of all stringer profiles available in different sections of fuselage. Determination of stress concentration factor for Web and Outer Flange of stringer profile covering entire ranges involves substantial number of Finite Element (FE) analysis. In order to optimise the number of FE runs, stress concentration factor is determined under worst repair factors combination (max. plate width; max. thickness; max. pitch; min. rivet dia.; and min. No. of rivets) resulting in conservative value. A parametric study of Web and Outer Flange data across stringer profiles were carried out and proven statistical techniques were used to find the optimal equation to predict stress concentration factor. This in turn reduced number of FE runs substantially for a given range of width, pitch, stringer thickness and so on. The use of optimal equation obtained through regression analysis is able to predict Kt within reasonable accuracy for a given range of inputs.