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Journal articles on the topic 'Landing gear leg'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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1

Miyata, Kazunori, Takamasa Sasagawa, Takahiro Doi, and Kenjiro Tadakuma. "A Study of Leg-Type Landing Gear for Aerial Vehicles - Development of One Leg Model -." Journal of Robotics and Mechatronics 23, no. 2 (April 20, 2011): 266–70. http://dx.doi.org/10.20965/jrm.2011.p0266.

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The novel aerial landing gear we propose has multiple articulated legs requiring no flat facilities such as landing fields. Smooth landing in rough terrain is enabled by multiple articulated legs changing shape and mechanical impedance as needed. For soft landings, it decreases velocity from fast to slow. Mechanical leg design is discussed and soft landing performance demonstrated.
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2

Doi, Takahiro, Kazunori Miyata, Takamasa Sasagawa, and Kenjiro Tadakuma. "Multi-Leg System for Aerial Vehicles." Journal of Robotics and Mechatronics 24, no. 1 (February 20, 2012): 174–79. http://dx.doi.org/10.20965/jrm.2012.p0174.

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The multi-leg system concept for aerial vehicles proposed here is a novel alternative to conventional landing gear and realizes adaptation to undulating terrain, shock absorption, ground-surface gripping, and chassis support after landing. The sections that follow discuss multi-leg system concept, mechanical shock absorption design, simulation, and experimental results.
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3

Gerhardinger, David, Anita Domitrović, and Ernest Bazijanac. "Fatigue Life Prognosis of a Light Aircraft Landing Gear Leg." Annual Conference of the PHM Society 12, no. 1 (November 3, 2020): 9. http://dx.doi.org/10.36001/phmconf.2020.v12i1.1245.

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Aircraft components are subject to fatigue damage. The prediction of fatigue life has significant influence on maintenance and flight operations. Light aircraft, designed for recreational purposes, have vital components that are subject to a hard time maintenance approach. The focus of this article is on a simple method for predicting fatigue life. The method is applied to a light aircraft’s fixed landing gear leg. The landing gear leg is modelled in a computer aided design environment. The load spectrum is determined, based on a characteristic flight profile. Principal strains are determined with finite element analysis. Fatigue life is calculated with the Coffin-Manson low cycle fatigue relation. The Palmgren-Miner rule is applied, and cumulative damage is determined. The results are compared to actual landing gear leg fatigue damage and the hard time replacement interval which is given in the corresponding maintenance manual.
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4

Maeda, Takao, Masatsugu Otsuki, and Tatsuaki Hashimoto. "Protection against overturning of a lunar-planetary lander using a controlled landing gear." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 2 (December 12, 2017): 438–56. http://dx.doi.org/10.1177/0954410017742931.

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This paper describes an attitude control method to prevent the overturning of lunar and planetary landers. The proposed control method that is based on a variable-damping shock absorber for the landing gear is experimentally validated. Conventionally, the landing gear of lunar and planetary landers has a fixed shock attenuation parameter that is not used proactively for attitude control of the lander during the touchdown sequence. The proposed method suppresses any disturbance to the attitude of the lander by adjusting the damping coefficient of each landing leg independently, based on the angular velocity and displacement velocity of each landing leg. First, the control method for the variable damper is presented. Second, the result of a landing experiment conducted in a two-dimensional plane is shown. These results indicate that the proposed semi-active landing gear system is effective for preventing the overturning of the lander on inclined terrain.
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5

Lefánti, R., Gabor Kalácska, I. Oldal, and K. Petróczki. "Developing small-aircraft service and re-construction of landing-gear leg support." International Journal Sustainable Construction & Design 2, no. 1 (November 6, 2011): 99–105. http://dx.doi.org/10.21825/scad.v2i1.20465.

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The programs of air-operation and service in the aviation engineering - within this at light-aircraft too - takeplace according to rigorous regulations [6, 7]. There are such machine units and parts which regulation areincomplete, for instance such is the landing-shaft seating. We have developed a new maintenance modelbased on the traditional ones, which offers new information exchange modul for e.g. weak point reconstruction and uses paper based documentation and modern remote maintenance as well. Beside thenew model we have worked out a renewing solution of the often failed landing-gear leg support applyingfield and laboratory test and FEM modelling to fill up as an engineering example for the information modulof the new maintenance model.
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6

MIYATA, Kazunori, Takamasa SASAGAWA, Takahiro DOI, and Kenjiro TADAKUMA. "1A2-C22 A study of Leg-type Landing Gear for Aerial Vehicles : Development of One Leg Model." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2010 (2010): _1A2—C22_1—_1A2—C22_4. http://dx.doi.org/10.1299/jsmermd.2010._1a2-c22_1.

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7

Bagrov, K. V. "Numerical simulation of planar oscillations of a landing gear leg along the longitudinal axis of an aircraft during the landing impact." Sibirskii zhurnal industrial'noi matematiki 22, no. 3 (June 14, 2018): 3–7. http://dx.doi.org/10.33048/sibjim.2019.22.301.

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8

Bagrov, K. V. "Numerical Simulation of Planar Oscillations of a Landing Gear Leg along the Longitudinal Axis of an Aircraft During the Landing Impact." Journal of Applied and Industrial Mathematics 13, no. 3 (July 2019): 385–89. http://dx.doi.org/10.1134/s1990478919030013.

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9

SASAGAWA, Takamasa, Kazunori MIYATA, Takahiro DOI, and Kenjiro TADAKUMA. "1A2-O01 A Study of Leg-type Landing Gear for Aerial Vehicles : Development of Two Leg Model(Aerial Robot and Mechatronics)." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2011 (2011): _1A2—O01_1—_1A2—O01_4. http://dx.doi.org/10.1299/jsmermd.2011._1a2-o01_1.

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10

DOI, Takahiro, and Kenjiro TADAKUMA. "2A1-I08 A Study of Leg-type Landing Gear for Aerial Vehicles : Development of Flying Three Leg Modelt(Aerial Robot and Mechatronics(1))." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2012 (2012): _2A1—I08_1—_2A1—I08_2. http://dx.doi.org/10.1299/jsmermd.2012._2a1-i08_1.

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11

Feekings, Jordan, Peter Lewy, and Niels Madsen. "The effect of regulation changes and influential factors on Atlantic cod discards in the Baltic Sea demersal trawl fishery." Canadian Journal of Fisheries and Aquatic Sciences 70, no. 4 (April 2013): 534–42. http://dx.doi.org/10.1139/cjfas-2012-0273.

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The proportion of Atlantic cod (Gadus morhua) discarded in the Danish Baltic Sea cod trawl fishery has been as high as 40%. This, combined with a stock that has declined dramatically over the past 30 years, has led to numerous technical regulations being introduced to reduce the capture of juveniles and thus discards. One method that has been widely adopted in the Baltic Sea has been to improve gear selectivity, subsequently allowing young individuals to escape capture. To understand the effects that changes to gear selectivity and minimum landing size have had on discard rates, as well as the effects of a range of additional explanatory factors, generalized additive mixed models were used. Gear regulation changes enforced in the Danish demersal trawl fishery in the Baltic Sea and other factors, such as minimum landings size, juvenile abundance, catch mass, price, and their spatial and temporal distribution, were found to significantly affect discard rates. The newest and currently legislated gears were identified as having the lowest discard rates. The increase in minimum landing size from 35 to 38 cm has increased discard rates.
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12

SUSANA, RATNA, USEP ALI ALBAYUMI, and NICKY ILHAM TRIADHY. "Perancangan dan Realisasi Kontrol Prototype Landing Gear System Menggunakan PLCmikro berbasis Mikrokontroller PIC16F877A." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 2, no. 1 (January 1, 2014): 15. http://dx.doi.org/10.26760/elkomika.v2i1.15.

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ABSTRAKLanding gear system merupakan suatu sistem penggerak pada roda pesawat yang menggunakan electromechanic system dengan sejumlah relay tanpa control terpusat. Melalui penelitian ini, electromechanic system tersebut diubah menjadi landing gear system yang dikendalikan secara terpusat menggunakan mikrokontroller dan diprogram oleh ldmikro berbahasa ladder diagram yang kemudian lebih dikenal dengan nama “PLCmikro”. Input discreate digunakan untuk menggerakkan aktuator solenoid valve agar piston double acting cylinder dapat bekerja sesuai sistem yang diinginkan. Input analog digunakan sebagai informasi ketinggian pesawat minimum agar pesawat tetap aman terbang di udara. Control Landing gear system yang direalisasikan berhasil menggerakkan piston masuk maupun keluar dari tabung, memberikan informasi proses pergerakkan piston yang bermasalah dan posisi roda yang telah masuk atau keluar dari pesawat berupa lampu LED. Sistem ini juga berhasil membaca informasi ketinggian minimum pesawat dari potensiometer serta mengubahnya menjadi informasi suara dan lampu LED.Kata kunci: Landing gear system, PLCmikro, Ldmikro, ladder diagram, double acting cylinder.ABSTRACTThe landing gear system an aircraft wheel drive system that uses electromechanic system with a relay without any centralized control. Through this study, the electromechanic system was changed to landing gear system with a centrally controlled by using microcontroller and programmed with ldmikro ladder diagram language which came to be known by the name of "PLCmikro". Discreate input used to drive the actuator solenoid valve double acting cylinder so that the piston can work as desired system. The analog input is used as the minimum flight altitude information to keep the plane safe to fly in the air. Landing gear control system is realized successfully drive the piston in and out of the tube, providing information processes are problematic piston movement and wheel position that has entered or exited the plane in the form of LED lights. The system also successfully read the minimum altitude aircraft information of the potentiometer and turn it into information sounds and LED lights. Keywords: Landing gear system, PLCmikro, Ldmikro, ladder diagram, double acting cylinder.
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13

Scheglov, G. A., and R. O. Lukovkin. "Dynamic crushing of spacecraft landing gear with crash legs." Journal of Physics: Conference Series 1348 (December 2019): 012080. http://dx.doi.org/10.1088/1742-6596/1348/1/012080.

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14

Stanislawski, Jaroslaw. "A simulation investigation of helicopter ground resonance phenomenon." Aircraft Engineering and Aerospace Technology 91, no. 3 (March 4, 2019): 484–97. http://dx.doi.org/10.1108/aeat-11-2017-0256.

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Purpose The purpose of this paper is to present a simulation method applied for investigation of helicopter ground resonance phenomenon. Design/methodology/approach The considered physical model of helicopter standing on ground with rotating rotor consists of fuselage and main transmission gear treated as stiff bodies connected by elastic elements. The fuselage is supported on landing gear modeled by spring-damper units. The main rotor blades are treated as set of elastic axes with lumped masses distributed along blade radius. Due to Galerkin method, parameters of blades motion are assumed as a combination of bending and torsion eigen modes. A Runge–Kutta method is applied to solve equations of motions of rotor blades and helicopter fuselage. Findings The presented simulation method may be applied in preliminary stage of helicopter design to avoid ground resonance by proper selection of landing gear units and blade damper characteristics. Practical implications Ground resonance may occur in form of violently increasing mutual oscillations of helicopter fuselage and lead-lag motion of rotor blades. According to changes of stiffness and damping characteristics, simulations show stable behavior or arising oscillations of helicopter. The effects of different blade balance or defect of blade damper are predicted. Originality/value The simulation method may help to determine the envelope of safe operation of helicopter in phase of take-off or landing. The effects of additional disturbances as results of blades pitch control as swashplate deflection are introduced.
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15

Cardoso, Inês, Teresa Moura, Hugo Mendes, Cristina Silva, and Manuela Azevedo. "An ecosystem approach to mixed fisheries: technical and biological interactions in the Portuguese multi-gear fleet." ICES Journal of Marine Science 72, no. 9 (August 12, 2015): 2618–26. http://dx.doi.org/10.1093/icesjms/fsv138.

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Abstract The term “mixed fisheries” refers to fishing activities where more than one species are caught simultaneously and one species may be fished by different gears. Therefore, mixed fisheries present a harder challenge for fisheries management than single-species fisheries and the uncertainty can start at the definition of the target species. In these particular fisheries, we have a large group of species that are caught, being target or not, species with large landing values that are actually not target, and species with a high economic value that can fall in the bycatch category. Although the dynamics of such fisheries is poorly understood, they are known to have a relevant contribution to Portuguese fishers' revenue. The present demand on sustainable fishing activities to ensure marine ecosystem preservation has led towards an ecosystem approach where effort is being made to take into account biological and technical interactions on management measures and advice. In this work, logbooks data of the Portuguese multi-gear fleet were used to identify different fisheries based on catch composition and gears through cluster analysis (CLARA). Two identified fisheries were used to explore the impact of these fishing activities on the ecosystem scale. This approach was achieved by a productivity and susceptibility analysis and through foodweb analysis. The relation between species vulnerability and their functional role in the ecosystem were highlighted. Technical interactions among fishing gears, and species biological interactions, were explored within and among fisheries. We found and illustrated that these interactions go beyond the fleets and fisheries considered in the present work. This approach allows us to identify key elements that can, ultimately, be relevant to an ecosystem-based approach towards mixed fisheries management.
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16

Natsir, Mohamad, Agustinus Anung Widodo, Wudianto Wudianto, and Sveinn Agnarsson. "TECHNICAL EFICIENCY OF FISH AGGREGATING DEVICES ASSOCIATED WITH TUNA FISHERY IN KENDARI FISHING PORT – INDONESIA." Indonesian Fisheries Research Journal 23, no. 2 (February 12, 2018): 97. http://dx.doi.org/10.15578/ifrj.23.2.2017.97-105.

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Kendari fishing port is one of the biggest tuna fisheries landing in Indonesia. It yearly average tuna production was more than 20 thousand tons. The tuna fishing fleet in Kendari use FAD (Fish Aggregating Devices) as an auxiliary fishing gear. FAD management is major issues in Indonesian tuna fisheries. extensive investment on FAD has led to increase of the juvenile and by catch and also social problem because of the competition. Technical efficiency analysis was done during this study, 2015 catch and logistic data from Kendari fishing port was run using stochastic frontier to obtain the model. Mean value technical efficiency was 0.534. Purse seine the highest mean value compared to other fishing gear. All the variables input show positive relationship to the catch except the days at sea variables, this is a signal that the increasing number of FAD has made the fisherman spend more time at sea it will decrease the technical efficiency. The results support the need of FAD regulation done by the government of Indonesia. Regulation will keep the number of FAD at optimum level and increase the technical effieciency so the fisheries keep gaining the optimum benefit from the resources.
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17

Gorpenko, A. O., O. I. Semenets, O. M. Doniy, and K. O. Valuiska. "Effect of the chassis parts surface condition from high-strength titanium alloy VT-22 in the process of fatigue tests." Uspihi materialoznavstva 2021, no. 2 (June 1, 2021): 45–53. http://dx.doi.org/10.15407/materials2021.02.045.

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The research focuses on the influence of the surface condition on the resource of high-strength titanium alloy VT-22 landing gear details during fatigue tests. The tests were performed on special facilities that simulate the workload on a rod detail at the stage of extending and retraction of the landing gear. Fatigue tests were performed on four rods. Rods № 1-3 were destroyed at the lugs level, rod №4 withstood the entire cycle of loads, and was examined in an undamaged state. It was found that the cause of the failure of the rod №1 was axial play formation as a result of bracket lug deformation, which led to shock loads on the lug of the rod №1 during the tests. The destruction of the rod №2 could be caused by the shock axial loads due to changes in the characteristics and load values of the facility on the rod №2. The priority factor influencing the premature failure of the rod №3 was the high risks from surface machining in the most loaded part of the rod №3, namely at the R-junction of the cylindrical part to the lug. The presence of surface defects formed during the manufacturing stage, as well as the presence of deep scratches in the area with high load reduce the life of rod № 3 fivefold compared to the undamaged rod № 4, which had no visible surface defects. Surface damage detected in the non-chromized area of the rods can be eliminated by blasting with subsequent surface polishing, which will provide the required resource of the detail (rod № 4). Keywords: high-strength titanium alloy VT-22, rod, fatigue tests, surface defects, structure of the surface layer.
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18

Suuronen, Petri, Vesa Tschernij, Pekka Jounela, Daniel Valentinsson, and P.-O. Larsson. "Factors affecting rule compliance with mesh size regulations in the Baltic cod trawl fishery." ICES Journal of Marine Science 64, no. 8 (September 5, 2007): 1603–6. http://dx.doi.org/10.1093/icesjms/fsm124.

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Abstract Suuronen, P., Tschernij, V., Jounela, P., Valentinsson, D., and Larsson, P-O. 2007. Factors affecting rule compiance with mesh size regulations in the Baltic cod trawl fishery. – ICES Journal of Marine Science, 64: 1603–1606. In this study, we evaluate the efficiency and applicability of a series of gear-based management measures, enforced since 1990, whose purpose was to improve size selectivity in the trawl fishery for Baltic cod (Gadus morhua). In general, our study revealed that these measures had no marked effect on the capture and discard of young cod. Legal and illegal manipulation of selective codends was widespread. The adoption of a codend design that offered a modest increase in selectivity, but had a good match with the legislated minimum landing size (MLS), led to greater compliance, demonstrating that a mismatch between MLS and selectivity should be avoided. It was also obvious that, generally, the fishing industry did not tolerate large short-term losses. Our evaluation is that overly ambitious rules will be circumvented, and frequent and incoherent changes in the regulations represent bad management practice. A gradual introduction of restrictions and participation by fishers in the decision-making process will increase compliance.
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19

Tubman, Lucky Cinny, Kariuki Muigua, and Nzioka John Muthama. "Assessment of the Influence of Beach Management Units on Fisheries Governance in Migingo Island, Kenya." Journal of Sustainability, Environment and Peace 4, no. 2 (August 26, 2021): 47–57. http://dx.doi.org/10.53537/jsep.2021.08.002.

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Beach Management Units (BMUs) in Kenya were established to ensure sustainable utilization and management of the fishery resource. BMUs as co-management institutions were conceptualized after the failed state-controlled fisheries management. Sustainable management by the BMUs has however not been realized, years after the institution’s inception. The study aimed to assess the management of Migingo BMUs; establish the effects of management of BMUs on the implementation of the regulations; and assess the implementation of regulations with regards to fish stocks. The study was done in Migingo Island, Lake Victoria which borders Kenya and Uganda. Data was collected from the BMU committee members and stakeholders at the fish landing site along the island’s shores. This was done through a questionnaire based survey; semi structured interviews from key informants and; focus discussion groups. Results revealed that the three out of seven functions were performed satisfactorily by the Migingo BMU. These were revenue collection, confiscation of illegal gears and arrest of offenders, as depicted by the satisfaction of respondents at 42%, 38%, and 68%, respectively. The other functions - conducting meetings, patrol of the lake, formulation of bylaws and inventory keeping had poor performance. Migingo’s BMU structure was found to be wanting as it lacked the assembly branch. Implementation of regulations by the BMU faced various challenges; lack of support from the government, inadequate funds and equipment and inadequate knowledge to operate its functions. This study shows that BMUs are viable institutions however the poor structure and management of Migingo’s BMU along with the challenges faced in implementing the stipulated regulations led to its ineffectiveness. Capacity building is therefore needed on the BMU’s management and governance at large, provision of relevant skills, equipment and funds and improved support from the government for the BMU to be efficient and effective.
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20

León, Benjamin, Julian J. Rimoli, and Claudio V. Di Leo. "Ground and Flight Tests of an Unmanned Rotorcraft with Cable-Driven Robotic Landing Gear." Journal of the American Helicopter Society, 2021. http://dx.doi.org/10.4050/jahs.66.042003.

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Robotic landing gear enhances the landing capabilities of vertical take-off and landing aircraft on sloped, rough, and even moving landing surfaces. This research demonstrates the integration and systematic testing of a robotic landing gear system for the commercial S-100 Camcopter, expanding the aircraft’s landing capabilities to currently inaccessible terrains with slopes at and above 15°. An overview of the mechanical design, sensors, and controller as integrated into the S-100 rotorcraft is provided along with expected landing performance from simulations tools. The system is then demonstrated using ground and flight experiments, and performance metrics are found to match design metrics. An asymmetry in left and right leg landings during flight testing is observed and analyzed. Lastly, cross-coupling of pitch and roll rates induced by the rotor is discussed as a cause of the asymmetry on this three-legged rotorcraft.
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21

Nadan, Paul M., Tatiana M. Anthony, Duncan M. Michael, Jeffrey B. Pflueger, Manik S. Sethi, Kelli N. Shimazu, Mindy Tieu, and Christopher L. Lee. "A Bird-Inspired Perching Landing Gear System1." Journal of Mechanisms and Robotics 11, no. 6 (September 30, 2019). http://dx.doi.org/10.1115/1.4044416.

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Abstract The design, modeling, simulation, and testing of a landing gear system that enables a UAV to perch on an object or surface is presented here. The working principle of the landing gear is inspired by the anatomy of birds that grasp and perch as tendons in their legs and feet are tensioned. In a similar fashion, as the UAV sets down on a structure, its weight tensions a cable which actuates opposing, flexible, multi-segment feet to enclose the target. To analyze the grasping capability of the design, a hybrid empirical–computational model is developed that can be used to simulate the kinematics of the system as it grasps objects of various cross-sectional shapes and sizes. The model relates the curvature of the feet to the displacement and tension of the cable tendon. These quantities are then related to the weight of the UAV through the leg geometry. It also evaluates enclosure and calculates contact forces to quantitatively characterize the grasp. Results demonstrate how the model can be used by designers to determine how a UAV can perch upon a structure of a given shape and size. If perched, the minimum weight required to maintain its position is calculated. A prototype system was fabricated, analyzed, and tested on a radio-controlled hexacopter. Experiments show that the landing gear enables the hexacopter to land, perch, and takeoff from a variety of objects. Finally, we begin to investigate the scalability of the concept with a smaller, lighter design.
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22

Krishnan, Arjun, Ashwin Krishnan, and Mark Costello. "Suppression of ground resonance in rotorcraft using active landing gear." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, June 9, 2021, 095441002110230. http://dx.doi.org/10.1177/09544100211023008.

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This article examines the fundamental aspects of controlling ground resonance in rotorcraft equipped with actively controlled landing gear. Ground resonance is a mechanical instability affecting rotorcraft on the ground. It occurs at certain rotor speeds, where the lead–lag motion of the rotor couples with the motion of fuselage creating a self-excited oscillation. Typically, passive or semi-active lag dampers are used to avoid instability; however, these are undesirable from a design and maintenance perspective. Innovations in active landing gear for rotorcraft, such as articulated robotic legs, have provided an alternate approach to avoid the instability, eliminating the need for lag dampers with respect to ground resonance. This article extends classic ground resonance to include movable landing gear and identifies key physical parameters affecting dynamic behavior. Applying LQ optimal control to this model, it is shown that ground resonance instability can be eliminated using active landing gear as the control mechanism, even when there is no lag damping present in the rotor. In addition, while superior performance is achieved when landing gear movement can occur both longitudinally and laterally, it is still possible to stabilize ground resonance with inputs in a single direction, albeit with reduced performance.
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23

Susana, Ratna, Usep Ali Albayumi, and Furqon Syah Bugar. "IMPLEMENTASI FUNCTION BLOCK DIAGRAM PADA SIMULATOR KONTROL LANDING GEAR SYSTEM UNTUK RODA PESAWAT." Jurnal Elektro dan Telekomunikasi Terapan 3, no. 2 (January 30, 2017). http://dx.doi.org/10.25124/jett.v3i2.301.

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Landing gear system pada beberapa pesawat masih menggunakan sistem elektromekanik dengan sejumlah kumpulan relay tanpa kendali terpusat. Penelitian ini akan mencoba menggantikan relay elektromekanik tersebut dengan menggunakan smart relay agar menjadi rangkaian yang lebih sederhana. Selanjutnya sistem dapat dikendalikan dan diprogram secara terpusat. Sistem yang diimplementasikan berupa simulator kontrol dari landing gear system menggunakan smart relay dengan bahasa pemrograman Function Block Diagram (FBD). Berdasarkan perancangan, instruksi FBD untuk implementasi sistem menggunakan instruksi OR, Set-Reset dan Timer. Dengan instrusksi tersebut, simulator ini telah berhasil menggerakkan piston Double Acting Cylinder (DAC) sehingga roda pesawat dapat bergerak naik dan turun, serta dapat memberikan sejumlah informasi kepada pilot melalui indikator berupa buzzer dan sejumlah LED. Pengujian dilakukan untuk 6 kondisi, yaitu pesawat di darat, lepas landas, di udara, pesawat terbang rendah, mendarat dan kondisi pergerakan DAC yang bermasalah. Keseluruhan sistem telah bekerja sesuai dengan spesifikasi sistem.
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24

Silva, Priscila M., Célia M. Teixeira, Cristina Pita, Henrique N. Cabral, and Susana França. "Portuguese Artisanal Fishers’ Knowledge About Elasmobranchs—A Case Study." Frontiers in Marine Science 8 (September 23, 2021). http://dx.doi.org/10.3389/fmars.2021.684059.

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The high economic value of fisheries was historically associated to commercial teleost fishes. Since the 1970s, despite some elasmobranchs becoming an important target or a bycatch, relatively little research has been carried out on this group because of their low economic value. Due to their specific life history characteristics, sharks and rays are particularly vulnerable to overexploitation, taking several decades to recover after reaching an overexploitation status. In Portugal elasmobranch fishery results mainly from targeted longlining and bycatch from different fishing gears. During the last decade, the Total Allowable Catches (TACs) of rays have been decreasing, the European Union (EU) banned the capture of some ray species, the Portuguese government implemented both a closed season and a minimum landing size for some rays, and the EU prohibited target fishing for sharks. All these measures may have been highly responsible for the national and local landings reduction. Official landings from the last decade were analyzed, the landed species conservation status was consulted, and structured interviews using a questionnaire were conducted in the most important fishing port in the Portuguese mainland, the port of Sesimbra. Results led us to conclude that fishers’ answers and landings data did not match. It also revealed a lack of awareness by fishers about the state of shark and ray populations, and about some aspects of their biology and ecology, like reproduction season and method. The present study highlights the need to fill in this existing gap in knowledge through the transfer of scientific knowledge and sharing of management responsibilities. Also, we aimed to demonstrate the necessity for awareness and education activities within fishing communities, an essential step to elasmobranch conservation.
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25

Van der Merwe, Lene, George Ruthven, and Konrad Von Leipzig. "The study and design of a national supply chain for the aerospace titanium components manufacturing industry." Journal of Transport and Supply Chain Management 6, no. 1 (November 26, 2012). http://dx.doi.org/10.4102/jtscm.v6i1.29.

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Titanium’s strength-to-density ratio, corrosion resistance and high thermal compatibility makes it the perfect metal for aerospace. Titanium is for instance used for the structural airframe, seat tracks, engine components and landing gear of aircraft. The Boeing 787 that had its test flight in 2009 is one of the latest aircraft designs that incorporates a substantially higher percentage of parts manufactured from titanium due to the weight benefit. Titanium’s extensive use in aerospace applications ensures that the aerospace market is the main driver of titanium metal demand. South Africa is the second largest titanium producer in the world after Australia. The abundance of titanium in South Africa together with the growing demand has led it to be identified as a beneficiation priority in a collaborative government initiative, called Titanium Beneficiation Initiative (TBI). The purpose of this paper is to develop a supply chain model for the anticipated South African titanium component manufacturing industry.
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26

Kasana, Shivraj Singh, and OP Pandey. "Effect of multipass cold plastic deformation and heat treatment on the mechanical properties of C250 marageing steel for aerospace applications." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, February 20, 2021, 146442072198937. http://dx.doi.org/10.1177/1464420721989373.

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The present investigation is aimed to reduce the cost of production of various components fabricated by using cold rolled C250 marageing steel in the aerospace applications like landing gears of aeroplane and spacecraft. As cast C250 marageing steel was forged and solution annealed as per the specification of the customer. Forged C250 steel was cold rolled from 15 to 300%. Microstructure analysis revealed that grains got refined and elongated in the direction of cold working. Cold drawing increases the hardness, tensile strength and yield strength. However, loss in ductility and impact strength was observed. Scanning electron microscope fractographs of tensile and impact samples showed elongation of the dimples in cold working direction. The increase in cold working reduces the size of dimples indicating the transformation of fracture nature from the ductile-to-brittle regime. At higher cold working, >170% led to intergranular tearing and resulted in a loss of impact and mechanical properties of the steel. Further, cryogenic treatment of cold rolled C250 steel delayed ageing causing increase in tensile and yield strength with a marginal loss in ductility. The cost estimation of C250 steel revealed a significant cost saving (Indian Rupees [INR] 7500/1000 kg) for components made from different diameters of cold rolled steel over the solution annealed steel.
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27

Kumar, James Sathya, P. Sam Paul, Girish Raghunathan, and Divin George Alex. "A review of challenges and solutions in the preparation and use of magnetorheological fluids." International Journal of Mechanical and Materials Engineering 14, no. 1 (November 28, 2019). http://dx.doi.org/10.1186/s40712-019-0109-2.

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AbstractThis review of MRF (magnetorheological fluids or MR fluids) brings out the challenges in methods of preparation, difficulties encountered in storage and use, and possible solutions to overcome the challenges.Magnetorheological fluid in the rheological fluid domain has found use due to its ability to change its shear strength based on the applied magnetic field. Magnetorheological fluids are composed of magnetizable micron-sized iron particles and a non-magnetizable base or carrier fluid along with additives to counter sedimentation and agglomeration.Magnetorheological fluids can respond to external stimuli by undergoing changes in physical properties thus enabling several improved modifications in the existing technology enhancing their application versatility and utility. Thus, magnetorheological fluid, a rheological material whose viscosity undergoes apparent changes on application of magnetic field, is considered as a smart material. Such materials can be used for active and semi-active control of engineering systems.Many studies on the designs of systems incorporating MR fluids, mainly for vibration control and also for other applications including brakes, clutches, dynamometers, aircraft landing gears, and helicopter lag dampers, have emerged over last couple of decades. However, the preparation as well as the maintenance of magnetorheological fluids involves several challenges. Sedimentation is a major challenge, even when stored for moderate periods of time. A comprehensive review is made on the problems confronted in the preparation of magnetorheological fluids as well as sustenance of the properties, for use, over a long period of time. Other problems encountered include agglomeration and in-use thickening (IUT) as well as rusting and crusting. Of interest is the mitigation of these problems so as to prepare fluids with satisfactory properties, and such solutions are reviewed here. The control of magnetorheological fluids and the applications of interest are also reviewed.The review covers additives for overcoming challenges in the preparation and use of magnetorheological fluids that include incrustation, sedimentation, agglomeration, and also oxidation of the particles. The methodology to prepare the fluid along with the process for adding selected additives was reviewed. The results showed an improvement in the reduction of sedimentation and other problems decreasing comparatively. A set of additives for addressing the specific challenges has been summarized. Experiments were carried out to establish the sedimentation rates for compositions with varying fractions of additives.The review also analyzes briefly the gaps in studies on MR fluids and covers present developments and future application areas such as haptic devices.
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