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Keywords = flange clearance

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17 pages, 8210 KiB  
Article
Study of Parameters Influencing Wrinkles in the Deep Drawing of Fiber-Based Materials Using Automatic Image Detection
by Yuchen Leng, Cedric Wilfried Sanjon, Qingxiang Tan, Peter Groche, Marek Hauptmann and Jens-Peter Majschak
J. Manuf. Mater. Process. 2024, 8(6), 237; https://doi.org/10.3390/jmmp8060237 - 24 Oct 2024
Viewed by 1283
Abstract
The evaluation of wrinkles in deep-drawn fiber-based materials is crucial for the assessment of product quality and the optimization of manufacturing processes. Wrinkling is a common phenomenon in the deep-drawing process and is caused by tangential compressive stresses on the flanges of the [...] Read more.
The evaluation of wrinkles in deep-drawn fiber-based materials is crucial for the assessment of product quality and the optimization of manufacturing processes. Wrinkling is a common phenomenon in the deep-drawing process and is caused by tangential compressive stresses on the flanges of the blank. This phenomenon is particularly prevalent for fiber-based materials with high tensile depths and can seriously affect the appearance and mechanical properties of the final product. The objective of this study is to identify the key process parameters affecting wrinkling and to deepen the understanding of their roles and interactions using wrinkle data for deep-drawn paper products. Image analysis techniques are employed, supported by a specially constructed darkroom platform to ensure uniform light intensity for capturing photographs. An automated program is developed for the detection and evaluation of wrinkle characteristics and distribution, which allows the free choice of the region to be detected and the representation of the wrinkle geometry not limited by the number. To enhance the precision of this program, the ellipticity is initially rectified for products without flanges, specifically cup-shaped deep-drawn products. The ellipticity is caused by the pronounced springback effect of the paperboard. The approach is employed to investigate the impact of material properties, blank holder force, drawing depth, drawing clearance, and punch speed on wrinkling formation after the deep-drawing process. The findings reveal that the blank holder force and drawing clearance are critical factors in wrinkle formation, with higher blank holder force generally leading to increased wrinkle numbers. Full article
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16 pages, 7819 KiB  
Article
Thermo-Mechanical Coupling Analysis of the Sealing Structure Stress of LNG Cryogenic Hose Fittings
by Liang Yang, Miaoer Liu, Yun Liu, Tao Zhang, Hailong Lu, Qingzhen Lu and Jun Yan
J. Mar. Sci. Eng. 2024, 12(4), 581; https://doi.org/10.3390/jmse12040581 - 29 Mar 2024
Cited by 1 | Viewed by 1678
Abstract
A cryogenic hose is used to transport liquefied natural gas at sea, where flexible fittings are sealed by corrugated lining and end flange welding. However, the extreme cryogenic temperatures of the conveyed fluid introduce substantial challenges to the integrity of the fitting seals’ [...] Read more.
A cryogenic hose is used to transport liquefied natural gas at sea, where flexible fittings are sealed by corrugated lining and end flange welding. However, the extreme cryogenic temperatures of the conveyed fluid introduce substantial challenges to the integrity of the fitting seals’ structure during the LNG transfer process. In order to study the sealing performance of the fitting under LNG conveying conditions, this paper was based on the general finite element software ABAQUS 6.11 to carry out a thermo-mechanical coupling analysis of the end sealing stress. This paper also established a sealing performance analysis model of the corrugated fitting welding area under the fitting action of LNG load and internal pressure load. A sensitivity analysis was conducted on the influence of weld clearance, blunt edge size, and weld residual height on the weld stress of a fitting ring. The results show that, under the combined action of the medium internal pressure and cryogenic load, the size design of the weld area significantly affects the sealing performance of the fitting, among which the equivalent force of the weld clearance butt sealing area has the greatest impact. Moreover, it was found that a pressure of 5 MPa was 2 mm when the weld clearance was 2 mm, and the average stress at the weld was 53.68 MPa. Further, considering the synergistic influence of the blunt edge size, the weld clearance was 3 mm, the stress was minimal when the blunt side size was 4 mm, and the average stress was 17.42 MPa. These research results can serve as a reference for the design and analysis of the sealing structure of non-adhesive inner corrugated cryogenic hose fittings. Full article
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26 pages, 3905 KiB  
Article
Cost Optimization of Prestressed U-Shaped Simply Supported Girder Using Box Complex Method
by Muhammad Salman Khan, Tianbo Peng, Syed Muhammad Ali, Faisal Ur Rehman and Yicheng Wu
Sustainability 2023, 15(14), 11457; https://doi.org/10.3390/su151411457 - 24 Jul 2023
Cited by 6 | Viewed by 2328
Abstract
The use of U-shaped girders has become increasingly popular in advanced projects such as metro rail systems due to their ability to provide greater vertical clearance beneath bridges. These girders, characterized by two webs and a bottom flange, contribute essential longitudinal stiffness and [...] Read more.
The use of U-shaped girders has become increasingly popular in advanced projects such as metro rail systems due to their ability to provide greater vertical clearance beneath bridges. These girders, characterized by two webs and a bottom flange, contribute essential longitudinal stiffness and strength to the overall structure while effectively countering torsional forces in curved bridges. However, the design and construction of U-shaped girders present challenges, including their relatively higher self-weight compared to other girder types. Consequently, cost optimization has become a crucial focus in structural design studies. This research aims to develop an optimization model for prestressed U-shaped girders using the AASHTO LRFD bridge design specifications. The model is based on the Box complex method, with necessary modifications and improvements to achieve an optimal design. The objective is to minimize the total cost of materials, including concrete, steel reinforcement, and prestressing strands, while satisfying explicit and implicit design constraints. To facilitate the analysis, design, and optimization processes, a program is developed using Visual Studio 2010 and implemented in Visual Basic (VB.NET). The program incorporates separate subroutines for analysis, design, and optimization of the prestressed U-shaped girder, which are integrated to produce the desired results. When running the program, the optimization process required 229 iterations to converge to the optimal cost function value. The results demonstrate that the developed algorithm efficiently explores economically and structurally effective solutions, resulting in cost savings compared to the initial design. The convergence rate of the moment capacity constraint is identified as a key factor in achieving the optimal design. This research makes a significant contribution to the field of civil engineering by applying the classical Box complex method to the optimization of girders, an area where its utilization has been limited. Furthermore, this study specifically addresses the optimization of prestressed U-shaped girders in metro rail projects, where they serve as both the deck and support structure for train loading. By employing the Box complex method, this research aims to fill the research gap and provide valuable insights into the optimization of U-shaped girders. This approach offers a fresh perspective on designing these girders, considering their unique role in supporting metro rail loads. By leveraging the benefits of the Box complex method, researchers can explore new possibilities and uncover optimal design solutions for U-shaped girders in metro rail applications. Full article
(This article belongs to the Section Sustainable Engineering and Science)
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19 pages, 8849 KiB  
Article
Research on the Relationship between Stall Propagation and Flange Leakage of Mixed-Flow Pumps
by Dele Lu, Wei Li, Shuo Li, Leilei Ji and Yi Yang
Water 2022, 14(11), 1730; https://doi.org/10.3390/w14111730 - 28 May 2022
Cited by 2 | Viewed by 2195
Abstract
In order to explore the internal relationship between stall core propagation and flange leakage flow in the rotating stall of a mixed-flow pump, based on the k-ε turbulence model, a SIMPLEC algorithm and hexahedral structured grid are used to simulate the internal flow [...] Read more.
In order to explore the internal relationship between stall core propagation and flange leakage flow in the rotating stall of a mixed-flow pump, based on the k-ε turbulence model, a SIMPLEC algorithm and hexahedral structured grid are used to simulate the internal flow field of the mixed-flow pump. By setting the flange clearance as 0.2 mm, 0.5 mm and 0.8 mm, the propagation characteristics of the rotating stall and the unsteady characteristics of flange leakage flow of the mixed-flow pump under the condition of near stall are studied, and the influence of the flange clearance on the pressure fluctuation characteristics of the mixed-flow pump under the condition of near stall is analyzed. The results show that the stall core is located at the outlet of the impeller and propagates from the leading edge of the adjacent blade along the opposite direction of blade rotation to the next flow channel. The pressure gradient in the stall channel and the energy loss are large. When the flange clearance is 0.5 mm and 0.8 mm, the stall core changes from one to two, and the propagation mechanism of the stall core tends to be complex in the two adjacent flow channels. When the flange clearance is 0.8 mm, the propagation period decreases. The variation law of leakage flow is consistent with the propagation law of stall core. When the flow passage changes from stall state to non-stall state, the leakage flow also changes from one state to another, so the leakage flow can be used as a form of apparent stall. Under the condition of near stall, the pressure fluctuation curve of the adjacent monitoring points has a large phase difference consistent with the propagation period of the stall core, and has a strong pressure drop. When the flange clearance is 0.5 mm and 0.8 mm, the time domain curve of pressure fluctuation has two wave troughs in one cycle. In the near stall condition, the main frequency of the pressure fluctuation at the monitoring point is the stall frequency, and the amplitude of the main frequency at the middle of the outlet is the largest. The characteristics of flange leakage flow and pressure fluctuation can better reflect the flow situation in the pump when rotating stall occurs. The research results can provide a basis for judging whether stall occurs in the flow passage of the pump. Full article
(This article belongs to the Special Issue CFD in Fluid Machinery Design and Optimization)
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19 pages, 15382 KiB  
Article
Influence of Fit Clearance and Tightening Torque on Contact Characteristics of Spindle–Grinding Wheel Flange Interface
by Qianqian Yuan, Yongsheng Zhu, Ke Yan and Xinzhuo Zhang
Machines 2022, 10(5), 298; https://doi.org/10.3390/machines10050298 - 22 Apr 2022
Viewed by 3227
Abstract
The spindle and grinding wheel flange (GWF) adopt double positioning of a tapered surface and end face. Due to the processing quality, the contact state of the spindle–GWF interface cannot be determined accurately. Based on the theory of finite element and the Yoshimura [...] Read more.
The spindle and grinding wheel flange (GWF) adopt double positioning of a tapered surface and end face. Due to the processing quality, the contact state of the spindle–GWF interface cannot be determined accurately. Based on the theory of finite element and the Yoshimura integral method, an analysis method for the contact stiffness of the spindle–GWF interface was established. In addition, the effects of the spindle–GWF interface’s original clearance and tightening torque on the contact pressure, final contact state and contact stiffness of the spindle–GWF interface were investigated and experimentally verified. It was found that the final contact state of the spindle–GWF changed when the tightening torque increased, especially when the original contact state was tapered contact, and the final contact state changed significantly after assembly. The contact pressure and contact stiffness of the spindle–GWF interface are increased by increasing the tightening torque. The radial stiffness is more affected by the end clearance variation compared to the axial and angular stiffness. When the original contact state is tapered contact, the radial stiffness of the interface is at maximum in three contact states. This research provides theoretical guidance for GWF assembly on gear-grinding machines. Full article
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29 pages, 5812 KiB  
Review
A Review of Fibre Reinforced Polymer Structures
by Jawed Qureshi
Fibers 2022, 10(3), 27; https://doi.org/10.3390/fib10030027 - 8 Mar 2022
Cited by 93 | Viewed by 17177
Abstract
This paper reviews Fibre Reinforced Polymer (FRP) composites in Civil Engineering applications. Three FRP types are used in Structural Engineering: FRP profiles for new construction, FRP rebars and FRP strengthening systems. Basic materials (fibres and resins), manufacturing processes and material properties are discussed. [...] Read more.
This paper reviews Fibre Reinforced Polymer (FRP) composites in Civil Engineering applications. Three FRP types are used in Structural Engineering: FRP profiles for new construction, FRP rebars and FRP strengthening systems. Basic materials (fibres and resins), manufacturing processes and material properties are discussed. The focus of the paper is on all-FRP new-build structures and their joints. All-FRP structures use pultruded FRP profiles. Their connections and joints use bolting, bonding or a combination of both. For plate-to-pate connections, effects of geometry, fibre direction, type and rate of loading, bolt torque and bolt hole clearance, and washers on failure modes and strength are reviewed. FRP beam-columns joints are also reviewed. The joints are divided into five categories: web cleated, web and flange cleated, high strength, plate bolted and box profile joints. The effect of both static and cyclic loading on joints is studied. The joints’ failure modes are also discussed. Full article
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21 pages, 5732 KiB  
Article
Effect Mechanism and Performance Evaluation of Flange Contact Thermal Resistance in an Aero-Engine
by Yan Chen, Liyuan Chen and Wuli Chu
Aerospace 2022, 9(3), 121; https://doi.org/10.3390/aerospace9030121 - 26 Feb 2022
Cited by 7 | Viewed by 4352
Abstract
According to the discontinuous structural characteristics of a gas turbine, by considering the contact thermal resistance of the rough surface, a contact thermal resistance measurement experiment was conducted in this study. The main objectives of this work were to investigate the influence mechanism [...] Read more.
According to the discontinuous structural characteristics of a gas turbine, by considering the contact thermal resistance of the rough surface, a contact thermal resistance measurement experiment was conducted in this study. The main objectives of this work were to investigate the influence mechanism and change law of the contact thermal resistance characteristics on flange installation. Furthermore, this study conducted a theoretical analysis of contact thermal resistance and the calculation of a typical flange mounting edge based on actual operating conditions. The research results show that the contact thermal resistance of a typical flange mounting edge increases with an increase in flange clearance under different tightening torques, which is essentially proportional to the flange clearance. As the flange clearance increases, the unit contact thermal conductivity firstly decreases rapidly. Then, as the flange clearance reaches 0.4 mm, the decreasing rate of unit contact thermal conductivity tends to flatten. In addition, the contact thermal resistance of the typical flange mounting edge decreases with the increase in the tightening torque under different flange clearances. Furthermore, the contact area ratio is not related to the material, and the contact thermal resistance under actual working conditions can be calculated using the unit contact area. Full article
(This article belongs to the Section Aeronautics)
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15 pages, 2600 KiB  
Article
Multi-Objective Parameter Optimization for Cross-Sectional Deformation of Double-Ridged Rectangular Tube in Rotary Draw Bending by Using Response Surface Methodology and NSGA-II
by Honglie Zhang, Yuli Liu and Chunmei Liu
Metals 2017, 7(6), 206; https://doi.org/10.3390/met7060206 - 5 Jun 2017
Cited by 8 | Viewed by 5273
Abstract
Cross-sectional deformation of double-ridged rectangular tube (DRRT) inevitably occurs due to the inhomogeneous deformation induced by external boundary conditions in rotary draw bending (RDB). Unreasonable factor combination would aggravate the cross-sectional deformation of DRRT. So, a powerful and efficient method combining Response Surface [...] Read more.
Cross-sectional deformation of double-ridged rectangular tube (DRRT) inevitably occurs due to the inhomogeneous deformation induced by external boundary conditions in rotary draw bending (RDB). Unreasonable factor combination would aggravate the cross-sectional deformation of DRRT. So, a powerful and efficient method combining Response Surface Methodology (RSM) and Non-Sorted Genetic Algorithm II (NSGA-II) was proposed to optimize the factors to control the cross-sectional deformation of DRRT in RDB. Firstly, an orthogonal experiment was used to screen out the important factors. It was obtained that three factors—clearance between DRRT and mandrel, clearance between DRRT and bending die, and boosting of pressure die—have an important influence on the cross-sectional deformation of DRRT. It can also be observed that the variation trend of flange sagging (FS) is always consistent with that of space deformation between ridges (SDR) with the changing of factors. RSM based on a Box-Behnken design was then used to establish response surface models. The proposed response surface models were used to analyze the relationship of the important parameters to the responses, such as space deformation between ridges, and width deformation of outer and inner ridge grooves (WDO and WDI). Finally, multi-objective parameter optimization for the cross-sectional deformation of DRRT in RDB was performed by using the established model and NSGA-II algorithm. The interaction of responses was revealed and the value range of each response in the space of Pareto optimal solutions was determined. It can be observed that there is always an evident conflict between SDR and WDO in the space of Pareto optimal solutions. By using this optimization method, the absolute values of SDR and WDI were significantly reduced—by 13.17% and 17.97%, respectively—compared with those before optimization, while WDO just increase only a little. Full article
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