Flange Coupling Research Articles

Fatigue strength assessment of preloaded cross-toothed flange connections based on the FKM guidelines

Cross-toothed flange connections are used in drivetrains for form-fit coupling of shafts. They belong to the group of non-shiftable couplings. Compared to frictional connections, tooth flange connections can transmit significantly higher torques in the same space. In contrast to other tooth couplings, the crossed tooth flange coupling investigated here is characterized by a particularly complex load distribution. The preload force, which is necessary to transmit operational loads, is generated by tensioning bolts, which can be located centrally or decentralized. Thus, the stress condition in the notch of the coupling is always determined by a superposition of stresses from preload force and operating loads.Extensive experimental and simulative investigations were carried out as a part of a research project. In addition to the development of a pragmatic, specially adapted calculation concept for cross-toothed couplings for practice, the experimental tests were accompanied by calculations with the FKM guideline “Analytical Strength Assessment” and the FKM guideline “non-linear”, The determination of local stresses was carried out with the help of elasticity theoretical and elastic-plastic FE full-contact calculations based on experimentally determined material data.This article deals with the possibilities of calculations based on the FE simulation results using the above mentioned FKM guidelines. The experimentally determined load-carrying capacity is critically compared to the calculation results. The focus is on the implementation of the fatigue strength analysis in the context of the corresponding boundary conditions. Topics such as the assumed knee point of the Wöhler curve to the fatigue strength range are discussed as well as the evaluation options for elastic-plastic FE results for the guideline „non-linear”.

Performance Evaluation of a Micro-Steam Turbine Powered Electric Generator under Changeable Bed and Drive Mechanisms

Machines are growth engines of the economy; each sector of the economy achieves its demand by the use of the machine. They are installed in various establishments for the purpose of using them to perform certain functions or others. However, as a result of the kind of forces, dynamic and static loads, they transmitted to their adjoining surroundings when used, they are often mounted on supporting structures, foundations or a combination of them to achieve adequate or appropriate safe operation and stability. When a machine is operating, it is subjected to several time-varying forces and as a result of which it tends to exhibit vibrations. In such a situation or process, a certain quantity of this force is transmitted to the foundation, which could undermine the life of the foundation and also affect its performance and the operation of any other machines on the same foundation. Hence, it makes sense to minimize this force transmission. This research aimed at developing an adjustable steel-framed structure for supporting the major components of a 5.0 kW micro-steam power unit (steam, turbine and alternator) and evaluating the performance of the unit with or without the vibration isolator when they are axially connected with flexible flange coupling or transversely connected with sets of belts and pulleys, in succession, respectively. The results showed that reduction in the force transmitted to the supporting structure occurred when the vibration produced by the unit is isolated from its base by the use of a vibration isolator, maximum reduction of 99.95% achieved when axially coupled and 99.91% when transversely connected with belt and pulley system. The results also showed that better performance would be attained when the steam turbine is axially coupled to the alternator than when connected with belt and pulley; The maximum voltage of 52 V and speed of 1000 rpm at 77 dB sound level attained with coupling connection, and voltage of 20 V and speed of 752 rpm at 75 dB with belt and pulley connection.

CALCULATING TARGET THRESHOLDS FOR THE MARGIN VALUE METHOD USING COMPUTATIONAL TOOLS

AbstractOverspecification or excess margin in a design can enhance its ability to absorb changes and uncertainty, but also deteriorates performance criteria such as weight and cost. This paper shows how the Margin Value Method (article in review) can be applied in conjunction with CAE tools such as FEA to quantify excess margin where a design is too complex for algebraic analysis. This new application context for the MVM is illustrated using a case study of a flange coupling design, in which topology optimisation is used within the MVM to identify opportunities for design improvement.

An automated workflow for integrating environmental sustainability assessment into parametric part design through standard reference models

Abstract Integrating environmental sustainability assessment into parametric design presents an opportunity for enabling sustainable product design. However, this is a challenging task as quantitative methods for sustainability assessment are poorly integrated with parametric design and optimization tools. Furthermore, current streamlined approaches for computing environmental impact during the design stage often ignore manufacturing-related impacts resulting from the geometric complexity of parts. To address these gaps, we present a systematic workflow for computing environmental indicators from parametric design models. Our workflow utilizes the unit manufacturing process information model to evaluate manufacturing-phase resource consumption from process planning data, and consequently enables quantitative correlation of design parameters to the calculated environmental indicators. We demonstrate our workflow through a case study involving the design of a rigid flange coupling, wherein we evaluate the influence of geometric design parameters on the corresponding environmental impact of the design.

Measuring the static shear strength of anaerobic adhesives in finite thickness under high pressure

ABSTRACT Although anaerobic adhesives are extensively used in addition to mechanical tightening in flanged couplings, interference fits, and threaded connections, their constitutive behaviour still needs to be investigated. According to the micromechanical model proposed by Dragoni and Mauri [Proc. of the IMECHE Part L J. of Mat.: Des. and Appl. 2002; 216: 9–15], the shear strength of the anaerobic adhesives significantly improves with the contact pressure applied to the thin adhesive layer. In order to assess this hypothesis, this work investigates the shear strength of an anaerobic adhesive layer with finite thickness and surface area, subject to a nearly-uniform contact pressure, up to 1000 MPa. The tests involved a head to head bonded specimen, made of high strength steel adherends (39NiCrMo3), with a controlled roughness on the bonding surfaces. Both a weak and a strong anaerobic adhesive (Loctite 243 and Loctite 638) are investigated. A full-field technique, such as the Digital Image Correlation, was used in order to detect the 3D displacement and strain fields, and to evaluate the twist angle of the entire external surface, with particular attention to the interface area. The preliminary results prove the reliability of the test bench and confirms the piezo-resistive response of the anaerobic adhesive.

The Development and Modeling of an Innovative Process of Forming the Internal Toothing of Flange Coupling Spline Sleeves

The Development and Modeling of an Innovative Process of Forming the Internal Toothing of Flange Coupling Spline Sleeves

Characterization of metallic seals to be used in the waveguide flange coupling of the ITER electron cyclotron upper launcher first confinement system

The ITER Electron Cyclotron Heating Upper Launcher (ECHUL) will be used to drive current locally inside magnetic islands located at the q=2 (or smaller) rational surfaces in order to stabilize neoclassical tearing modes (NTMs). Each of the fours antennas consists of eight beam lines, totaling 12.8m that are designed for the transmission of up to 1.5MW of mm-wave power at 170GHz, with at least 90% of the power in the main HE11 mode.Each transmission line consists of a Z shaped set of straight corrugated, aluminum alloy waveguides connected by miter bends with a nominal inner diameter of 50mm. The FCS system also encompasses intrinsic components such as: closure plate, mm-waveguide taper, isolation valve, diamond window and an EU-US interface waveguide.All FCS components are connected via a dedicated flange coupling, with a bolted connection, comprising of two concentric metallic seals in order to satisfy the SIC-1 requirements. The coupling shall be capable of resisting the applied external loads and displacements, including thermal cycles due to ohmic losses in the transmission line, and also adhere to the matting of different materials (EN AW-6082, CuCrZr, SS 316L) while maintaining ultra-high vacuum tightness (10−8mbar).The present study will use a dedicated experimental apparatus for the characterization of the mechanical and vacuum properties of a single metallic seal under compression, with applied heat flow. In order to ensure reproducibility of the components mechanical characteristics, randomly chosen metallic seals of each diameter have been tested from two independent manufactures (A and B).

Модернизация соединений трубопроводов в машинах и оборудовании нефтегазовых промыслов

Introduction The problem of tight joint of pipelines and high pressure hoses (HPH) applied in various fields of human livelihood is considered. Special aspects of the high-pressure pipelines operation in the equipment of the oil and gas complex is as follows. At ambient temperatures below minus 50oC, it is needed to transmit thousands of tons of stratum fluids heated up to 200-250oC and containing aggressive media, abrasive and highly mineralized water. Materials and Methods. Various designs of metal seals applied in high pressure pipe connections are considered. Joints widely used for pipelines do not withstand pressures higher than 20-60 MPa. With that, in pipelines of the oil-industry equipment, pressure may exceed 100 MPa. A key feature of applying joints in question is to reduce their strength with increasing the diameter. These detriments confine the scope of use of the above-mentioned sealing schemes. It makes field repair of such joints, for example, during operation of oil and gas equipment, practically impossible. In this case, the use of quick connectors (Q/C) is required, for disassembling of which it is ample to have the keys. Research Results. For the solution to the specified problems, a principally new scheme of connection sealing for pipelines and HPH is developed and patented. The key element of the patented device is a stepped bushing which reliably seals the connection of pipelines and HPH. The stepped bushing (sealant) should be made of high-alloy steel by analogy with the joint in the flange couplings, and it can be hardened which will allow for increasing the strength of the connections in question and using them under low temperature conditions. Discussion and Conclusions. The comparative analysis of the sealing elements designs shows advantages of the proposed sealant. For its practical application, it is needed to optimize the shape and dimensions of the stepped bush in order to provide for leaktightness at given pressures, and, besides, to determine the required thread pull force to ensure safe performance of the unit.

Mechanics of unloading of a rough surfaces pre-loaded joint

In this paper we study the problem of the contact characteristics changing on a decrease of the load applied to the preloaded joint of roughness surfaces. The penetration of a rigid sphere (indenter) into the elastic hardenable half-space is considered originally. The elastic crater restoring by unloading is also considered. In elastic-plastic material´s describing, Hollomon´s pawer law is used. To describe a contact of a rigid rough surface with an elastic plastic half-space, the discrete model of a rough surface is used. Microasperities are represented as a set of identical spherical segments, the height distribution of which corresponds to the bearing profile curve of the surface. To describe the bearing profile curve, incomplete beta function ratio is used. The relations of relative contact areas ƞ and ƞ e and gap densities at the joint Λ e and Λ ce on dimensionless loading F q and F qe at loading and unloading for different values of ɛ y and n are given. The obtained results are of practical importance for the sealing ability prediction of fixed sealing joints at the design stage, in particular for tightness supply of flange couplings and high pressure vessels seals.

Influence of Materials Hardenability Parameters on the Machine Parts Characteristics after Unloading

This paper studies the problem of the relative area changing on a decrease of the load applied to the joint of roughness surfaces. The penetration of a rigid rough sphere (indenter) into the elastic hardenable half-space is initially considered, then the elastic crater restoring by unloading is considered. To defining elastic-plastic material, Hollomon’s power law is used. To describe a contact of a rigid rough surface with an elastic plastic half-space, the discrete model of a rough surface is used. Microasperities are represented as a set of identical spherical segments, the height distribution of which corresponds to the bearing profile curve of the real surface. The dependence the dimensionless force elastic-geometric parameter Fq on a relative amount of indentation ε at loading and the dependence of analogous parameter Fqe on amount of ε-Dε at unloading are obtained. The relations of relative contact areas h and he on dimensionless loading Fq and Fqe at loading and unloading for different values of a hardening exponent n and parameter are given. The obtained results are of practical importance for the performance prediction of fixed machine elements’ joints at the design stage, in particular for tightness supply of flange couplings and high pressure vessels seals.

Silent Flange Coupling Design Used for the Schenck Eddy Current Dynamometer

The silent flange used for coupling different machines/systems to an eddy current dynamometer represents one of the modular components each test-bench should use. By introducing a silent flange into a dynamometer, the coupling steps are easier and faster. For an appropriate design, the silent flange was analyzed using dedicated software during different operation procedures and scenarios, for materials that allow easy manufacturing. This study shows that the design for this silent flange model has no danger of failure due to the small deformation and the values for the equivalent stresses. The silent flange coupling is suitable for the dynamometer for his high positioning accuracy, the zero backlash and the fact that there is no motion between the shafts.

Failure Analysis of Flange Coupling with Two Different Materials

Failure Analysis of Flange Coupling with Two Different Materials

Experimental study to identify the effect of type of coupling on unbalance using frequency spectrum analysis

Any defect in machine will affect vibration behavior and nature of this effect is different for different faults. Understanding and practicing the fundamentals of rotating shaft parameters is the first step in reducing unnecessary vibration, reducing maintenance costs and increasing machine uptime. Hence condition monitoring based on vibration measurements can be used to identify those defects qualitatively. Vibration signals give early indication of mechanical failures such as misalignment, unbalance and bent shaft etc. The present study deals with experimental investigation of unbalance with the help of FFT analyzer and its unique vibration spectrum for different types of couplings such as jaw coupling, flexible flange coupling and rigid coupling. Understanding and practicing the fundamentals of rotating shaft parameters is the first step in reducing unnecessary vibration, reducing maintenance costs and increasing machine uptime. Many researchers have reported unbalance related faults show dominant peak at 1×. For experimental identification of unbalance an experimental setup is constructed and frequency spectrum is acquired for jaw coupling, flexible flange coupling and rigid flange coupling. These acquired spectrums are compared with available literature for confirmation of experiment results. The experimental results are in close agreement with results available in literature.

1105 数値解析によるフランジ形固定軸継手の負荷性能と強度の評価(GS-3 摩擦・摩耗)

1105 数値解析によるフランジ形固定軸継手の負荷性能と強度の評価(GS-3 摩擦・摩耗)

Numerical analysis of load capacity and strength of rigid flanged shaft couplings

Numerical analysis of load capacity and strength of rigid flanged shaft couplings

Set-based design of mechanical systems with design robustness integrated

This paper presents a method for parameter design of mechanical products based on a set-based approach. Set-based concurrent engineering emphasises on designing in a multi-stakeholder environment with concurrent involvement of the stakeholders in the design process. It also encourages flexibility in design through communication in terms of ranges instead of fixed point values and subsequent alternative solutions resulting from intersection of these ranges. These alternative solutions can then be refined and selected according to the designers’ preferences and clients’ needs. This paper presents a model and tools for integrated flexible design that take into account the manufacturing variations as well as the design objectives for finding inherently robust solutions using QCSP transformation through interval analysis. In order to demonstrate the approach, an example of design of rigid flange coupling with a variable number of bolts and a choice of bolts from ISO M standard has been resolved and demonstrated.

Finite Element Analysis of Universal Joint

The power produced from an engine of automobile can be transferred to the drive wheel by power transmission system. Each automobile has different power transmission system constructive features depend on vehicle's driveline concept. While transmitting a torque different stresses are induced such as tensional stress & bending stress are experienced. Finite element method is used as stress analysis to determine the stress conditions at a failed section. In this preproject seminar report, analysis of rigid flange coupling is carried out which is similar to the universal joint. In this Finite Element Method analysis of rigid flange coupling with the help of ANSYS Software for different torque and load condition and it verify by manual calculation. Index term: CV, ANSYS, FEM, .

Structural Analysis of a Flange Coupling without Clearance

In this paper the flange coupling without clearance will be analyzed using CATIA Generative Structural Analysis workbench. The structural analysis procedure will be presented: creating the 3D model, configuring the mesh, applying the restraints, applying the loads (torque), applying the interaction conditions (driving flange-bolts and nuts, bolts and nuts-driven flange), running the numerical analysis and results visualization. Two different systems will be analyzed: the first is a six bolts flange coupling working in nominal conditions, the second is a five bolts flange coupling working in some failure conditions with only five bolts distributed in a six holes flange coupling. In certain conditions the flange coupling design allows the same torque to be transmitted by six, but also by only five bolts. However, the non-uniformity of the five bolts distribution around the six holes flanges will generate some other unwanted phenomena. In this case all the stress and deformations will be non-symmetrically and for the flange coupling that is a rotating coupling this can be one reason for beats phenomenon.

발전용 축계 결합용 커플링 볼트 설계에 관한 연구

Coupling bolts have replaced conventional fitted bolts in applications where the operator's safety during assembly/disassembly is of concern or where the cost of process interruption is significant. Coupling bolts have been installed on rotating flange couplings in a wide range of marine and power applications worldwide. Their use has been approved by all leading international and national classification societies and regulatory bodies. A coupling bolt is a hydraulically tensioned fitted bolt that creates a stable and rigid link between coupling flanges and simplifies assembly and disassembly. We measure the bolt dimensions for reverse engineering and study the standard of assembly-load using a mechanical formula in order to localize a coupling bolt for a shaft in a power plant. We experimentally obtain the friction coefficient and confirm the condition of bolt sets through structure analysis. We show the variation of contact pressure for the shape parameter in order to consider the result when redesigning a bolt.

Transient thermal analysis of Vega launcher structures

A transient thermal analysis is carried out to verify the base cover thermal protection system of Vega 2nd stage Solid Rocket Motor (SRM) and the flange coupling of the inter-stage 2/3. The analysis is performed with a finite element code. The work has developed suitable numerical Fortran subroutines to assign radiation and convection boundary conditions. The thermal behaviour of the structures is presented.