Conical Components Research Articles

Comparative analysis and enhancement of conical component calculation under internal pressure in European pressure vessel Standards

This paper presents a comprehensive analysis of conical components in pressure vessels emphasizing their significance when utilized to transition between different diameters or slopes. A thorough design and analysis are underscored as essential for ensuring the safety and reliability of these components under diverse loading circumstances. The paper aims to propose enhancements to the European Pressure Vessel Standards concerning conical components under internal pressure, with a focus on improving safety, reliability, and compliance with industry standards. Existing European standards are reviewed, identifying potential gaps and proposing practical solutions. The paper also presents research findings on the influence of cone apex angles, shell geometries and design pressure on cone plate thickness calculations. A new methodology for the design and analysis of conical components in pressure vessels is proposed, offering a potential pathway to safer and more efficient pressure vessels. A range of cylinder diameter between 1000 and 2500 mm and cone angles between 30° and 60° are used as input to quantify the difference in cone thickness for a design pressure ranging between 10 and 200 barg. The proposed method yields results much closer to AD2000 compared to EN13445, leading to slightly thicker cones (up to 2.2 mm for the selected range of cone diameters and angles) compared to the former, resulting in safer pressure vessel design, and thinner cones (up to 22 mm) compared to the latter resulting in significant material savings. A comparative analysis was performed through Finite Element Analysis validating the EN13445 unsuitability for cone thickness calculations. A modification is proposed for equation (7.6)-(8) in EN13445 resulting in thinner plates reducing the cone plate thickness difference to 0.9 % on average compared to the current deviation of -9.6 % on average for the selected range of cylinder diameters and cone angles.

Hydro-mechanical deep drawing of conical components: Wrinkling behavior and process enhancement

This study explores the hydro-mechanical deep drawing process of a conical part through finite element simulations using ABAQUS software. The central focus is on investigating the occurrence of wrinkling during the forming process. Given the limitations in generalizing previous studies on wrinkling, there is a critical necessity to comprehensively comprehend and mitigate wrinkling behavior through an investigation into the interplay of various parameters. In response to the recognized challenge of minimizing wrinkles, an experimental setup with a hydro-mechanical deep drawing die was resented, aiming to validate and refine the simulation results. Additionally, a comprehensive study is conducted regarding the effect of fluid pressure, chamber pressure, pre-bulge height, friction coefficients, and sheet thickness on wrinkling behavior. The findings reveal that, at a pre-bulge pressure of 40 bar and a pre-bulge height of 2 mm, the minimum wrinkling height is observed to be merely 0.02 mm — the lowest recorded value. Notably, an increasing drawing ratio demands a 50% higher minimum chamber pressure to prevent wrinkling in the flange. Furthermore, a larger distance between the sheet and the die reduces the safe working range by approximately 57%, impacting the production of a wrinkle-free part. Conversely, elevating the pre-bulge pressure results in a 50% expansion in the safe working area for producing a wrinkle-free part. By explicitly stating the challenge of minimizing wrinkles, this study aims to contribute valuable insights into optimizing the hydro-mechanical deep drawing process for enhanced efficiency and improved product quality.

Preparation of the close cross-section component of NiAl-based alloy by a novel combined sintering method

In this study, to overcome the bottleneck of forming NiAl for aerospace applications, a novel combined sintering method based on hot-press sintering, which divides the components into various parts and compacts them gradually, is proposed and studied. Two typical close cross-sectional components (tube-like components and conical tube components with flanges), which are highly demanding and more challenging to obtain for NiAl intermetallic, were prepared and analyzed in detail. Based on these results, both prepared components were fully dense. In addition, as shown by the bending tests, the interfacial strength is between the strengths of the base alloys on the two sides, which confirms the reliable bonding ability achieved by this method. For the conical tube component with flange, the ultimate tensile strength of the combined-sintered part in 1000 ℃ is 406.7±3.2 MPa, and the ultimate strength of the pre-sintered part is 368.6±2.7 MPa, which are 39% and 26% higher than the strength of blade-like component prepared by casting and hot isostatic pressing (292 MPa). The proposed method discussed in our study can overcome the uneven density defects in HPS and achieve collaborative control of both the shape and performance when preparing a high height-to-thickness ratio or a complex-shaped close cross-section component.

Study on the Optimization of Heat Transfer Coefficient of a Rare Earth Wrought Magnesium Alloy in Residual Stress Analysis

To investigate the heat transfer coefficient (HTC) of a newly developed rare-earth wrought magnesium alloy under different cooling rates, the experiment of solution treatment followed by water quenching or air cooling process was carried out for calculation by lumped capacitance method (LCM) and optimized by inverse heat transfer method (IHTM), and cooling temperature curves were simulated afterward. In water quenching, the larger the temperature difference between the sample and water, the larger the maximum HTC, and the earlier it reached the maximum value, and in air cooling the HTC became larger with the airflow speeds increased. In LCM, the peak values of the HTC were 2840 W/(m2·°C) in water quenching and 54 W/(m2·°C) in air cooling. The corresponding HTC was 2388 W/(m2·°C) in IHTM. The maximum absolute average relative error (AARE) of temperature simulation in water quenching decreased from 8.46% in LCM to 2.45% in IHTM. The residual stress(RS) of a large conical component was simulated using both non-optimized and optimized HTC, the RS in the IHTM was ~30 MPa smaller than that in the ILCM, because the corresponding HTC was smaller, and the comparison of the simulation results with the measurements revealed that the RS using HTC in the IHTM is more accurate.

A hybrid soft material robotic end-effector for reversible in-space assembly of strut components.

Based on the NASA in-Space Assembled Telescope (iSAT) study (Bulletin of the American Astronomical Society, 2019, 51, 50) which details the design and requirements for a 20-m parabolic in-space telescope, NASA Langley Research Center (LaRC) has been developing structural and robotic solutions to address the needs of building larger in-space assets. One of the structural methods studied involves stackable and collapsible modular solutions to address launch vehicle volume constraints. This solution uses a packing method that stacks struts in a dixie-cup like manner and a chemical composite bonding technique that reduces weight of the structure, adds strength, and offers the ability to de-bond the components for structural modifications. We present in this paper work towards a soft material robot end-effector, capable of suppling the manipulability, pressure, and temperature requirements for the bonding/de-bonding of these conical structural components. This work is done to investigate the feasibility of a hybrid soft robotic end-effector actuated by Twisted and Coiled Artificial Muscles (TCAMs) for in-space assembly tasks. TCAMs are a class of actuator which have garnered significant recent research interest due to their allowance for high force to weight ratio when compared to other popular methods of actuation within the field of soft robotics, and a muscle-tendon actuation design using TCAMs leads to a compact and lightweight system with controllable and tunable behavior. In addition to the muscle-tendon design, this paper also details the early investigation of an induction system for adhesive bonding/de-bonding and the sensors used for benchtop design and testing. Additionally, we discuss the viability of Robotic Operating System 2 (ROS2) and Gazebo modeling environments for soft robotics as they pertain to larger simulation efforts at LaRC. We show real world test results against simulation results for a method which divides the soft, continuous material of the end-effector into discrete links connected by spring-like joints.

Experimental and numerical study of telescopic conical energy absorber under inversion process

In this article, a new model of a conical absorber with an inversion mechanism in form of a telescope is introduced. The purpose of this article is to decrease the initial peak load and improve drawbacks and limitations in the inversion mechanism. When the tube is subjected to axial loading, each component is inverted and moves toward the next component. Therefore, the dissipation of energy is occurred due to the curling of edges and circumferential contraction in the tube wall. The inversion process of tubes under axial compression is simulated using the ABAQUS nonlinear finite element code. To verify the numerical simulation, some experimental tests are carried out. Moreover, a parametric study has been conducted to investigate the geometric effects of tube including end-capped, numbers of conical components, semi-apical angle and edge length of components. The results show that with appropriate selection of geometric dimensions of the new conical absorber has a significant role in reducing the initial peak load without a noticeable change in the specific energy absorption.

Projective plane curves over a finite field with conical components

We present the list of maximal projective plane curves containing conics and those which are arrangements of conics. The number of rational points and the corresponding polynomials are given. The third highest number of points of projective curves of degree d over a finite field Fq (d < [q/3]) is associated only to some linear curves. We show that for q/2 + 2 < d < q, this is no longer the case: the third highest number of points can also be obtained by some curves containing a conic. Throughout this work, we obtain some bounds concerning the number of Fq-points of curves with linear, conic and cubic factors. these bounds apply (not sharply) to irreducible curves

Surface Mechanical Properties and Micro-Structure Evolution of 7075 Aluminum Alloy Sheet for 2-Dimension Ellipse Ultrasonic Vibration Incremental Forming: A Pretreatment for Laser Shock Peening

In this paper, a composite technique of ultrasonic incremental forming and laser shock peeing is proposed. The former process is mainly used for the manufacturing of complex-shaped sheet and strengthening coating that is prepared for subsequent laser treatment. The latter is applied for secondary surface reinforcement with ultra-high energy. This work focused on the novel ultrasonic incremental forming method and its effects on surface mechanical properties and micro-structure of a 7075 aluminum alloy. First, a kind of 2-dimension ellipse ultrasonic vibration incremental forming process and the unique double-mechanism method of sectionalized cooperative control of plastic deformation and mechanical performance were designed. Second, the single-point incremental forming, the longitudinal ultrasonic vibration incremental forming, and the 2 dimension ellipse ultrasonic vibration incremental forming were performed for the manufacture of conical components of 7075 aluminum alloy. Third, the Vickers micro-hardness testing results and images of the fracture morphology of the machined part for the novel technique confirm that softening mechanisms become dominant inside the metal sheet. Furthermore, a strengthening coating with excellent mechanical properties and a residual compressive stress field were created on its surface simultaneously. In a word, the research shows potential values of the proposed technique for the manufacture of aircraft panels of complex shape and excellent surface properties.

Contamination suppression of coupling glass during vacuum laser welding

In vacuum laser welding, a laser beam is irradiated into a chamber through a coupling glass exposed to contamination. A conical protective system for the coupling glass is suggested, and contamination is analysed via simulation and experiments based on the conical component height and the gas flow rate. Stable descending flow is a key to suppressing the contamination, which affects the particle ascending velocity, horizontal deflection of particles and number of residual particles. The laser transmission area can be protected using a gas flow rate of 1.0 L min−1 or a cone height of 90 mm for the conical component. The conical protective system demonstrates excellent contamination suppression capability. The simulation-based approach can provide an effective design for the protective system.

Porous materials saturated with water-copper nanofluid for heat transfer improvement between vertical concentric cones

Water-Copper nanofluid saturated porous materials are used to improve cooling of a conical electronic component contained in another concentric cavity of the same shape maintained at low temperature. Ratio between thermal conductivity of the solid matrix of the porous materials and that of the base fluid (water) varies between 4 and 41.2 while the nanofluid's volume fraction varies between 0% (pure water) and 10%. Free convective heat transfer was determined by means of a numerical approach based on the volume control method using the SIMPLE algorithm. Results show improvement of heat transfer as thermal conductivity ratio, nanoparticles concentration and Rayleigh number increase. Improvement was quantified through specific functions. New correlation is proposed to determine the average Nusselt number for any combination of the thermal conductivity ratio and nanofluid volume fraction in the 3.32x105-6.74x107 Rayleigh number range.

Modernization of the apparatus for grinding root crops

The sustainable functioning of the agro-industrial complex largely determines its scientific and technical support. One of the key directions of the development of agricultural science is the mechanization of animal husbandry processes. When solving a complex of problems, great attention is paid to the preparation of feed for feeding, namely the grinding of root-club crops. This makes it possible to significantly increase the return of each feed unit. As a result of a wide review of literary sources, a thorough analysis of modern designs of root-club grinders, it was possible to solve the technical problem of its modernization by creating a simple as well as reliable design. The peculiarity of the modernization consists in the fact that the electric motor is mounted on the cover of the housing with the help of a flange, which is its component element, besides, the axis of rotation of the shaft structure is aligned with the axis of rotation of the disk structure. Loading hopper is also installed on cover. For this purpose, the cover has a hole for the driving shaft of the electric motor, as well as a window for passage of root clubs from the cavity of the receiving hopper to the space of the housing. Disk is rigidly mounted on free edge of shaft structure. Body is fixed on base by means of uprights vertically and with formation of free space under its bottom and base for installation of unloading neck, as well as reservoir for treated root-club beds. The discharge neck is structurally made in the form of a funnel, moreover, with the formation of a conical component at the top and a cylindrical component at the bottom. In addition, the axis of symmetry of the funnel is aligned with the axis of rotation of the shaft. Its conical component is attached to the outer surface of the bottom structure, and the cylindrical component of the funnel is oriented to the container for the treated material. Concentric holes are made in bottom for passage of processed root-and-root beds from cavity of body into structure of discharge neck. The principle of energy saving is carried out by supplying treated fodder to the discharge neck device and further to the receiving vessel mainly due to gravity of the treated fodder.

Incremental bending of conic profiles on CNC hydraulic bending machines

Sheet metal forming processes for manufacturing truncated cones can be divided into methods which use shape related tooling to produce the required form, for example, spinning and deep drawing, and processes that utilise kinematics to produce the required geometry, for example, roller, air and swivel bending. Such kinematic forming methods can achieve high degrees of forming flexibility but require process models to avoid elaborate trial and error approaches. For the incremental manufacture of cones, CNC swivel bending as yet lacks such a process model. In addition, with the current ‘state of the art’ processes, the manufactured cones exhibit geometric defects with respect to concentricity and skewing. In this study, the operation of a CNC bending machine fitted with an upper beam that can be inclined was investigated. The proposed inclination of the beam corresponds to the desired conical shape of the product. The machine was provided with a radial sheet feed mechanism (back-gauge) to feed material in even segments between bent corners thus avoiding geometric imperfections. A plasto-mechanic process model was developed to deliver the process parameters for swivel bending of specific conical geometries. The process model was validated by numerical simulations and practical bending experiments. Coarsely segmented conical shapes can be manufactured using the analytically calculated process parameters. For conical geometries, the process modifications of sequential swivel bending showed satisfactory improvements in the initial bending defects, that is, lack of concentricity and skewing. Compared with the target geometries, a tendency towards larger diameters remained in the experiments and is explained by the boundary conditions of the sequential process and if a larger number of bending increments is carried out. The present study delivers a first approach to determine the process parameters for the sequential operation of a swivel bending machine in order to provide relevant process parameters for the industrial production of conical components.

Free vibration of FGM conical–spherical shells

Natural frequencies of a conical–spherical functionally graded material (FGM) shell are obtained in this study. It is assumed that the conical and spherical shell components have identical thickness. The system of joined shell is made from FGMs, where properties of the shell are graded through the thickness direction. The first order shear deformation theory of shells is used to investigate the effects of shear strains and rotary inertia. The Donnel type of kinematic assumptions are adopted to establish the general equations of motion and the associated boundary and continuity conditions with the aid of Hamilton’s principle. The resulting system of equations are discretized using the semi-analytical generalized differential quadrature (GDQ) method. Considering various types of boundary conditions for the shell ends and intersection continuity conditions, an eigenvalue problem is established to examine the vibration frequencies. After proving the efficiency and validity of the present method for the case of thin isotropic homogeneous joined shells with the data of conventional finite element software, parametric studies are carried out for the system of combined moderately thick conical–spherical joined shells made of FGMs and various types of end supports.

Identification of independent modes in two inputs free space communications system

The study proves the concept of using a system with two inputs laser-beam, modulated independently by helical and conical phase distributions followed by their superposition in the same physical path for free space optical communications. Both phase distributions generate annular intensities with specific geometry according to the modulating parameters. The modes are multiplexed in an emission unit and propagate via laboratory free space as rings with optimized radii, without interfering, to the reading phase mask of the receiving unit. The reading mask acts as matching filter which embeds planar phase information such that to distribute the helical and conical components on mutual perpendicular directions. Identification occurs when the parameters of the reading mask match those of the input modes as predicted by a 2-dim inner product model developed here and confirmed experimentally by the occurrence of maximum intensities in the specific centers. Splitting the matrix-like diffracted beam in enabler and processing branches allows to double check and to identify the matching cases by the properties of the associated histogram without affecting subsequent signal retrieval. Crosstalk levels are examined.

Conically refracted Gaussian beam transformed by a lens

ABSTRACT The free-space evolution of a conically refracted Gaussian beam after being imaged by a lens is studied both theoretically and experimentally. It is shown that, in contrast to the longitudinal symmetry of a regular conically refracted beam with respect to its focal plane, the imaged beam acquires a strong longitudinal asymmetry, similarly to other known coherent beams with complex internal structure evolving upon propagation. Paraxial amplitude expressions for the two conical refraction components of the imaged beam are derived as functions of the imaging lens focal length and of the magnification value. A very good agreement between theoretical and experimental results is demonstrated.

An experimental and theoretical study on constitutive model of Al-2024T4 for sheet metal incremental forming

Incremental sheet metal forming (ISF) is well known as a die less and flexible forming method and is widely used for prototype part fabrication. It can extremely improve the forming limit of sheet metal. But how to get the stress-strain curve of material with improved strain limit to be used for analysis of incremental forming process? Comparing with classic global forming method, sheet metal incremental forming is local forming method. It means that any time only a small zone of entire component is deforming and moving correspondingly with the forming tool head and is undergoing a complex loading history during the forming process. Based on these characteristics, in the present study, a constitutive model is proposed to describe the stress-strain curve of material and to research the mechanism of high forming limit phenomena in ISF experimentally and theoretically.Three aspects are focused on: firstly, a constitutive model is proposed to describe the stress-strain curve of material and to adapt to the complex loading history and to analysis the mechanism of high forming limit. Secondly, an incremental forming paradigm with truncated conical shape is conducted with geometrical relationship between tool and sheet metal to calculate the strain path of sheet metal around the tool head. Thirdly, the mechanical properties are gained by tension test before and after truncated conical component made by incremental forming. The forming limit diagram is obtained by measuring and calculating the grids printed on the surface of truncate conical component.The calculation algorithm with the proposed constitutive model is programmed to calculate the plastic forming strain and stress of truncated conical component during incremental forming process. The proposed constitutive model is compared with experimental results and can be used to analysis forming limit of incremental sheet metal forming.

Clinical outcomes of using a prosthetic protocol to rehabilitate tissue-level implants with a convergent collar in the esthetic zone: A 3-year prospective study

Statement of problemWhether increasing the space for peri-implant soft tissues by using implant systems with conical or convergent transmucosal components would improve tissue stability and esthetics is unclear. PurposeThe purpose of this prospective clinical study was to evaluate the clinical and esthetic outcomes of using tissue-level implants with a convergent collar in the esthetic zone that had been rehabilitated following the biological oriented preparation technique (BOPT) approach after a 3-year follow-up period. Material and methodsSixteen participants with at least 1 nonrestorable tooth in the maxillary anterior region or with congenitally missing maxillary lateral incisors were enrolled, and tissue-level implants with a convergent collar were inserted 3 months after extraction. The implants were restored with cemented single crowns designed according to the BOPT protocol. Bone resorption and the pink esthetic score were evaluated over a 3-year period. ResultsFifteen participants (mean age: 54.6 years) were evaluated over the 3-year period (total: 16 implants). One participant with 1 implant relocated dropped out of the study. The 3-year implant cumulative survival rate was 100%. The mean ±standard deviation bone-level change was 0.071 ±0.11 mm. The mean pink esthetic score was 8.5 ±1.59, range 4-10. ConclusionsThe use of the BOPT protocol to restore tissue-level implants with a convergent collar achieved good esthetic results and maintained stable soft and hard peri-implant tissues.

Double Sided Incremental Forming: Capabilities and Challenges

Incremental Sheet Forming (ISF) is gaining importance because of its flexibility to form customized/low volume sheet metal parts. Out of different variants of ISF, Double Sided Incremental Forming (DSIF) is most flexible variant which uses two tools, one to form the geometry and the other to provide local support. Complex geometries with features on both sides of sheet can be formed in single setup by changing the roles of forming and supporting tools based on the geometrical characteristics. This article presents the evolution of DSIF process, machines, methodologies and strategies to form complex geometries and their prediction. A multi-stage methodology is attempted to enhance the accuracy of large components is presented. Results show that the accuracy of a 250 mm × 250 mm size conical component is enhanced by 50% (maximum error reduced from 2.9 mm to 1.4 mm) using two-stage forming.

Region of Interest-Based 3D Inpainting of Cultural Heritage Artifacts

In this article, we address the problem of 3D inpainting using an exemplar-based method for point clouds. 3D inpainting is a process of filling holes or missing regions in the reconstructed 3D models. Typically, inpainting methods addressed in the literature fill missing regions due to occlusions or inaccurate scanning of 3D models. However, we focus on scenarios involving naturally existing damaged models, which are partly broken or incomplete in the artifacts at cultural heritage sites. We propose an exemplar-based inpainting technique using the region of interest (ROI)-based method to inpaint the missing regions of the damaged model. The ROI of a 3D model is represented as a set of Riemannian manifolds, and metric tensor and Christoffel symbols are used as geometric features to capture the inherent geometry. We then decompose the ROI into basic shape regions, namely, spherical, conical, and cylindrical components, and identify the best-fit match for inpainting. Instead of using a single similar exemplar for inpainting, we select the most relevant best-fit region to fill the missing region from the basic shape regions library obtained from n similar exemplars. We demonstrate the performance of the proposed inpainting method on artifacts at UNESCO World Heritage site Hampi temples, India with varying complexities and sizes for both synthetically generated holes and real missing regions in 3D objects.

Conical diffraction of Dark and Antidark beams modulated by a Gaussian profile in biaxial crystals

In this paper, we study the evolution of internal conical diffraction with a new type of laser beams family by concerning Dark and Antidark beams modulated by a Gaussian profile propagating along an optic axis of a biaxial crystal. Analytical expressions giving the outgoing conical diffraction components of the considered beams behind the crystal are derived in detail. With the help of numerical simulation, the present study shows the conical diffraction beam evolution in a biaxial crystal. Our results indicate to illustrate the effects of some parameters on propagation properties of produced beams, including the incident beam parameter α, the ratio between the conical refraction radius R0 and the waist radius of the input beam ω, and the propagation distance. The intensity pattern of circularly polarized Gaussian beam transformed by the effect of conical diffraction in a biaxial crystal is also discussed in this investigation as a particular case.