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The use of composite materials in the construction of an aircraft (adopted from Aerospace Technology Institute, 2017)
Source publication
The paper presents tribological tests of selected materials used as liners in a composite hydraulic cylinder. Three coating materials were used for the analysis: Sika F180 polyurethane, Huntsman Araldite LY1564 with Aradur 3487 amine hardener and Bezlona 1111 Super Metal. In addition, uncoated carbon epoxy laminate (CFRP) samples were used as refer...
Contexts in source publication
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... the aviation industry, the most popular are fibre composites reinforced with glass, carbon or aramid fibres in an epoxy resin matrix. The main areas of their application in airplanes are presented in Figure 1. ...
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... E f -energy dissipated due to friction, J; T -test duration, s; F f -friction force, N; s -displacement, m; t -time, s. Figure 7 shows sample cross-sections through the friction path, while Figures 8 to 11 show 3D scans of the friction path surface. Figure 12 shows the width of the friction trace for the tested materials, while Figure 13 shows the depth of wear. ...
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... E f -energy dissipated due to friction, J; T -test duration, s; F f -friction force, N; s -displacement, m; t -time, s. Figure 7 shows sample cross-sections through the friction path, while Figures 8 to 11 show 3D scans of the friction path surface. Figure 12 shows the width of the friction trace for the tested materials, while Figure 13 shows the depth of wear. ...
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... E f -energy dissipated due to friction, J; T -test duration, s; F f -friction force, N; s -displacement, m; t -time, s. Figure 7 shows sample cross-sections through the friction path, while Figures 8 to 11 show 3D scans of the friction path surface. Figure 12 shows the width of the friction trace for the tested materials, while Figure 13 shows the depth of wear. ...
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... Figures 7-13, i.e. 3D scans, profi les of crosssections and the depth and width of abrasion marks, it can be seen that epoxy has the worst wear kinetics (it has the highest friction force and the greatest depth and width of the path). At the same time, epoxy is characterised by a very smooth friction path, free of surface defects and microcraters. ...
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... e above wear mechanisms are confi rmed by the morphology of the wear path carried out by SEM analyses. Sample micrographs of friction paths are shown in Figure 14. ...
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... the case of the surface of Super Metal, cracks, chipping, and even detachment of pieces of material can be noticed, leading to the deterioration of tribological properties ( Figures 6, 10, 14b). Both the friction force and the amount of energy dissipated due to friction for this material were comparable with the values obtained for the reference material (CFRP) and F180. ...
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... the friction force and the amount of energy dissipated due to friction for this material were comparable with the values obtained for the reference material (CFRP) and F180. However, the width and depth of the abrasion are greater (Figure 12 and 13). Similar, although smaller, chipping can be observed on the surface of the CFRP material. ...
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... although smaller, chipping can be observed on the surface of the CFRP material. Figure 14d clearly shows the need to use anti-wear coatings on an uncoated carbonepoxy laminate due to the tearing off of large fragments of the laminate (especially when placed perpendicular to the direction of movement). For CFRP, however, the friction force and wear were only slightly greater than for the F180. ...
Context 10
... the aviation industry, the most popular are fibre composites reinforced with glass, carbon or aramid fibres in an epoxy resin matrix. The main areas of their application in airplanes are presented in Figure 1. ...
Context 11
... E f -energy dissipated due to friction, J; T -test duration, s; F f -friction force, N; s -displacement, m; t -time, s. Figure 7 shows sample cross-sections through the friction path, while Figures 8 to 11 show 3D scans of the friction path surface. Figure 12 shows the width of the friction trace for the tested materials, while Figure 13 shows the depth of wear. ...
Context 12
... E f -energy dissipated due to friction, J; T -test duration, s; F f -friction force, N; s -displacement, m; t -time, s. Figure 7 shows sample cross-sections through the friction path, while Figures 8 to 11 show 3D scans of the friction path surface. Figure 12 shows the width of the friction trace for the tested materials, while Figure 13 shows the depth of wear. ...
Context 13
... E f -energy dissipated due to friction, J; T -test duration, s; F f -friction force, N; s -displacement, m; t -time, s. Figure 7 shows sample cross-sections through the friction path, while Figures 8 to 11 show 3D scans of the friction path surface. Figure 12 shows the width of the friction trace for the tested materials, while Figure 13 shows the depth of wear. ...
Context 14
... Figures 7-13, i.e. 3D scans, profi les of crosssections and the depth and width of abrasion marks, it can be seen that epoxy has the worst wear kinetics (it has the highest friction force and the greatest depth and width of the path). At the same time, epoxy is characterised by a very smooth friction path, free of surface defects and microcraters. ...
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... e above wear mechanisms are confi rmed by the morphology of the wear path carried out by SEM analyses. Sample micrographs of friction paths are shown in Figure 14. ...
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... the case of the surface of Super Metal, cracks, chipping, and even detachment of pieces of material can be noticed, leading to the deterioration of tribological properties ( Figures 6, 10, 14b). Both the friction force and the amount of energy dissipated due to friction for this material were comparable with the values obtained for the reference material (CFRP) and F180. ...
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... the friction force and the amount of energy dissipated due to friction for this material were comparable with the values obtained for the reference material (CFRP) and F180. However, the width and depth of the abrasion are greater (Figure 12 and 13). Similar, although smaller, chipping can be observed on the surface of the CFRP material. ...
Context 18
... although smaller, chipping can be observed on the surface of the CFRP material. Figure 14d clearly shows the need to use anti-wear coatings on an uncoated carbonepoxy laminate due to the tearing off of large fragments of the laminate (especially when placed perpendicular to the direction of movement). For CFRP, however, the friction force and wear were only slightly greater than for the F180. ...
Citations
... 4,6 A small amount of pioneering work has been found on CFRP hydraulic tube without metal liner. Marek et al. [32][33][34][35][36] and Scholz et al. 37,38 studied the properties of coatings, but not the composite structure of heterogeneous material. Parker 39,40 developed CFRP tube, but the exact details are not reported. ...
Hydraulic cylinders are widely used in rudder surface control, landing gear retraction of aircraft. The aircraft could benefit a lot on weight reduction, by the application of the carbon fiber reinforced polymer (CFPR) on the hydraulic cylinder. The design, optimization, manufacture of the CFRP hydraulic cylinder tube without metal liner is systematically studied in this article. In terms of structure design, inspired by natural thorn plants, a bionic thorn‐tooth connection structure is designed to connect CFRP and the metal end. Then the theoretical design method of thorn‐tooth is proposed. It also provides a new solution for the generic technology of CFRP‐to‐metal connection. In terms of CFRP parameters design method, an accurate mechanical model of CFRP hydraulic tube is established, the influence law of CFRP parameters on mechanical properties is explored, and the optimization method of CFRP parameters adapted to new characteristics is proposed. In terms of the manufacturing process, the split manufacturing‐combined molding process with high precision and low cost is developed to fit the characteristics of CFRP hydraulic tube without metal liner. The prototype manufactured by the proposed method has a weight reduction ratio of 62.37% while maintaining performances compared to the original metal hydraulic cylinder tube. This research will bring significant performance gains and considerable economic and environmental benefits to aircrafts.
Highlights
The systematic study of CFRP hydraulic tube without metal liner is presented for weight reduction.
The bionic thorn‐tooth connection and its parameter design method are proposed.
The CFRP parameters design method of CFRP hydraulic tube is established.
A manufacturing process adapted to CFRP hydraulic tube without metal liner is developed.
... The aircraft hydraulics are used on aircraft of all sizes to operate most of their equipment such as landing gears, brakes, flaps, thrust reversers, and flight controls. Thus, the hydraulic system performs the function of moving and actuating the critical and the basic components, according to Leśniewski et al. (2022) and Urbanowicz et al. (2021). In the aircrafts, exist two main hydraulic system types: the basic hydraulic system and power hydraulic system, according to Aeroclass (2021) (Figure 1a). ...
Theoretical research on hydraulic processes occurring in aircraft hydraulic drives is presented in the studies. Installation of angular fitting connections in aircraft pipeline systems influences hydrodynamic processes and fluid flow characteristics analysed in the research. The provided analysis is based on a validated numerical model utilizing Navier–Stokes equations and the k-epsilon turbulence model. Fluid flow inside the aircraft hydraulic drive pipeline system was investigated with flow rates up to 100 l/min. A mesh independence study was conducted for numerical simulation of the fluid flow. The obtained results include fluid pressure drops, energy losses, and operational delays associated with fluid flow vortex formations at 45° and 90° angular fitting connections. Additionally, compared results from standard methods of calculation for angular fitting connections, including the equivalent length and equivalent length same shape methods.
... He supported his conclusions with experimental studies conducted in a university laboratory. Here, too, it was a pump system without a hydraulic pre-charging [29], who described solutions to water pumps, and G. E.M. Vael, P. A.J. Achten, and T. van den Brink [30], who presented floating cup pumps [31,32]. ...
... In order to derive analytical relationships for calculating the efficiency of the precharge pump assembly, simplifying assumptions were made that the physical processes occur in the system at a steady state, the system is vented and there are no cavitation Gordić, D.; and Petrović [29], who described solutions to water pumps, and G. E.M. Vael, P. A.J. Achten, and T. van den Brink [30], who presented floating cup pumps [31,32]. ...
The overall efficiency and energy consumption problem in hydraulic power pack units with and without an additional pre-charging system was analyzed in this paper. A theoretical mathematical model was developed for calculating energy losses in both pump unit structures. To verify the theoretical relationships, a laboratory test stand was built, upon which the results of calculating the overall efficiency were compared with the results of the laboratory tests. Universal diagrams of the overall efficiency dependence as a function of pressure load and geometric adjustment of the main pump’s working volume were created for the case of a particular hydraulic pump unit without and with a pre-charging system. Based on this, discussions were carried out on whether and the way in which the additionally pre-charging system affects the parameters of the overall efficiency characteristics of the researched pump unit. Additionally, the dependence of the optimal pressure load and the maximum overall efficiency of the pump unit on the geometric adjustment of the main pump’s working volume was analyzed. It was shown that the pre-charging system affects the increase in the optimal pressure load at which the most favorable operating conditions, in terms of energy consumption, are obtained for the researched hydraulic pump unit.
This research aims to investigate the flow characteristics of plastic valves with 3D-printed poppets using Computational Fluid Dynamics (CFD) simulations and experimental validation. Plastic valves have been gaining popularity in various industries due to their lightweight, corrosion resistance, and low cost. However, the use of plastic valves in fluid flow applications is still limited due to concerns about their durability and performance. The poppet, being the main component of a valve, plays a crucial role in determining the valve’s performance. In this study, poppets have been 3D printed using polylactic acid (PLA) material. Different poppets shapes were tested using CFD simulations and experimental tests to obtain pressure-flow characteristics. The numerical approach to obtain the valves flow characteristics includes the cavitation model to ensure better agreement with the experimental data. The results of this research provide insights into the suitability of plastic valves for various applications and the importance of experimental validation in the design process.
Hydraulic cylinders are widely used in aircraft rudder surface control, landing gear retraction, flaps and speed brakes retraction, ground steering driving, and engine thrust reverser control. The huge weight of hydraulic cylinders severely limits the aircraft's potential for increased range, maneuverability, energy efficiency, and carrying capacity. To achieve the maximum weight reduction, the carbon fiber reinforced polymer (CFRP) hydraulic tube without a metal liner is designed in this paper. In response to the lack of a parameter calculation method for CFRP hydraulic tubes, the accurate calculation method is developed through mechanical modeling and analysis of parameter influence law. For the structure design challenges of connection, sealing, and friction of CFRP hydraulic tube without metal liner, we have proposed and verified the wave contour inlaid structure, three leak‐proof solutions of the connection interface, the leak‐proof structure of the wound CFRP body and the seal friction pair. For the difficulties of multi‐material and high‐precision molding, a new process of split manufacturing‐combined molding is developed to achieve high‐precision and low‐cost manufacturing. Finally, the prototype is manufactured and tested by the presented method, and its weight reduction ratio is 56.64% compared with the original metal hydraulic tube. This study has further matured the application of CFRP hydraulic tubes without metal liners and has great lightweight benefits in aircraft.
Highlights
CFRP hydraulic tube without metal liner is designed to reduce weight.
An accurate calculation method of CFRP parameters is developed.
Connection structure, leak‐proof structure, and seal friction pair are designed.
The high‐precision and low‐cost molding process is innovatively proposed.
