Aircraft Loads Research Articles

The usability analysis of software loading tools in a commercial airline.

Aircraft software loading tools evolved as enhanced floppy disks and different types of portable data loaders emerged into the modern world. However, there was a lack of academic research centered on the usability of those tools. This study analyzed the usability of three aircraft software loading tools: floppy disks, Teledyne PMAT, and MBS mini PDL. A total of 20 avionics technicians answered 10 System Usability Scale (SUS) indicators and performed the software loading task. These professionals completed three sets of SUS questionnaires, one set for each software tool. Analysis of Variance (ANOVA) indicated that there were statistical differences in SUS score and completion time. The comparable SUS score and completion time pertained to the following tools: floppy disks & MBS mini PDL and Teledyne PMAT & MBS mini PDL. Pearson correlation analysis noted a significant positive relationship between SUS score & software tool. Moreover, there was a significant negative relationship between SUS score & completion time and software tool & completion time. However, avionics technicians' years of experience lacked a significant impact on SUS score and completion time. Ultimately, it was recommended to utilize MBS mini PDL. This aircraft loading tool had the most significant impact, highest SUS score, and fastest completion time. The researchers presented managerial implications if MBS mini PDL was utilized, including sales increase and overhead cost savings. Finally, this research was the first study that analyzed the usability of the commonly used aircraft software loading tools.

Streamlining logistics: Innovating cross-docking distribution systems for operational excellence

A logistics service company in Batam faces challenges related to warehouse load fulfillment and sorting inaccuracies. This study aims to identify proposed efficiency improvements to the goods distribution system using the cross-docking method. The research method chosen is cross-docking, a technique that eliminates the storage process in the warehouse, thus saving time and cost. The research findings show significant benefits, especially in achieving zero inventory efficiency. Data processing and discussion revealed that efficiencies were apparent by increasing the sorting tables from 1 to 6, with an output of 90,000 kg during aircraft loading and unloading (compared to approximately 77,000 kilograms). This efficiency arises from the larger output of the sorting tables compared to the input, eliminating the need for warehousing and adding ten trucks. As a result, the shipment can be completed in one trip, with no goods stored in the warehouse. The analysis shows that implementing cross-docking in the company increases efficiency in distributing goods to forwarding partners.

Reliability analysis of an aircraft load mechanism considering multi-site damage dependency

Aircraft load mechanisms are the important actuators of the aircraft rudder control systems. By sharing the same operation circumstances and working conditions, the damage processes at multiple sites are dependent. In this paper, we firstly conduct a wear experiment and a stress relaxation experiment of an aircraft load mechanism. To consider the individual variability of the damage processes, the stochastic processes are adopted. Then, vine copula function is introduced to analyze the multivariate dependence of the damage processes. Furthermore, a time-varying dependent model is formed to model the dynamic damage interaction. The reliability of the aircraft load mechanism is assessed by using the Rosenblatt transformation and Monte Carlo method. The obtained results show that overlooking the dependency will lead to a conservative reliability result. Finally, the effect of the damage processes on the mechanism is analyzed, which provides effective guidance for the maintenance of the mechanism.

A Novel Method for Aircraft Structural Dynamic Strain Trend Signal Processing via Optimized Parallel Computing

In this study, we investigate the underlying causes of drift in the time history curves of measured parameters obtained through strain electrical measurements and assess their impacts on load measurements. To address the challenge of efficiently processing large volumes of aircraft load data, we propose and analyze a multi-level parallel algorithm specifically designed for the data processing of aircraft load measurements. To achieve this objective, we discuss parallel processing at both medium- and fine-grained levels and develop two distinct parallel processing algorithms: one for coarse- and medium-grained aircraft-type data streams, and another for medium- and fine-grained takeoff and landing data streams. The efficacy of these algorithms is validated through the processing of load data measured on a specific aircraft wing. The results demonstrate that the proposed approach offers a novel technical pathway for large-scale scientific computations and enhances data processing efficiency in the domain of aircraft load spectrum analysis.

Research on load prediction of carrier-based aircraft landing test based on measured data

Abstract As one of the most important parts in the ground (carrier) landing process of carrier-based aircraft, undercarriage is directly related to the safety of the aircraft, the crew, and even the landing platform with its strength and stiffness. The landing test to evaluate the strength and stiffness of the undercarriage of the carrier-based aircraft has strict regulations on the sinking velocity of the aircraft during landing. Still, in consideration of safety, it is difficult for the aircraft to reach the sinking velocity specified in the test under normal conditions. In this thesis, based on a large number of measured flight data, the artificial neural network was used to reasonably predict the undercarriage landing load of carrier-based aircraft and improve the landing test points, thus providing a new idea for the research on undercarriage load strength.

Finite element algorithm for rigid pavement resting on Pasternak elastic foundation model under aircraft loading

Finite element algorithm for rigid pavement resting on Pasternak elastic foundation model under aircraft loading

Research on the Measurement and Estimation Method of Wheel Resistance on a Soil Runway

In view of the fact that there is no suitable measurement method for tire driving resistance during the operation of a transporter on soil pavement, this paper proposes a simple measurement and estimation method for driving resistance on a soil runway based on the Bekker settlement model. In this paper, using the driving resistance equation based on the Bekker model, a simplified equation of driving resistance related to mass is proposed. Using the principle of kinematics, a simple test device for driving resistance was developed, and the test data of the test device were used to determine the parameters of the driving resistance estimation equation of the road surface. The driving resistance of the wheel running state was tested by the simulated aircraft load loading vehicle through the mechanical sensor, and the consistency between the theoretical value and the actual value of the driving resistance value under 8T, 10T, and 12T loads was verified. This research shows that the test method and estimation method have low cost and good accuracy and are suitable for wide promotion. The results of this paper provide a new idea and method for estimating the driving resistance of a wheel when a transporter runs on a soil road and also provide a reference for designing the length of a soil runway.

Comparative Study of Airport Layer Thickness Planning Between US Army Corp Graphical Method and Federal Aviation Administration (FAA) PCN-ACN and PCR-ACR Method

Airport pavement is designed following the US Corporation of Engineers method or better known as the California Bearing Ratio (CBR) method and the FAA (Federal Aviation Administration) method which issues regulations for calculating airport pavement structures, namely AC (Advisory Circular) 150_5320_6D which same as the method CBR. In 2021, the FAA issued a standard for calculating airport pavement structures, namely AC (Advisory Circular) 150_5320_6G which uses the FAARFIELD assistance program. The difference in pavement thickness is at most 7.6 cm, on the flexible pavement type base course. In the FAARFIELD Auxiliary Program, all aircraft loads are taken into account as a contributor to pavement damage indicated by the CDF value that can accommodate aircraft loads, in contrast to the graphical method where aircraft are converted to design aircraft. The thickness of the base course using the graphical method is greater than that of the FAARFIELD Assistance Program, this is because when performing calculations, the initial base course value is the minimum value based on the minimum base course table for the use of top foundation layer material (AC No.150_5320_6G). The thickness of the surface course pavement is the same according to FAA provisions for the critical thickness of the surface course which is 4 in or 102 mm.

Design and analysis of a novel thermal management system for serving next-generation aircraft with megawatt-level heat loads

Due to the development of electronics and high-energy pulse devices, in conjunction with the increasing flight speeds, the instantaneous heat load of next-generation aircraft will reach the megawatt level, which poses severe challenges for thermal management. To improve the heat dissipation capability, this paper presents a novel thermal management system (TMS) employing liquefied natural gas (LNG). This TMS design incorporates four merits: LNG and fuel share the heat load of electronics which dramatically enhances the mission time; the air circulation subsystem selects different combinations of heat sinks depending on the engine's operational state; LNG spray cooling efficiently handles the heat load of directed energy weapons; the heat sinks release the cooling capacity in a temperature gradient to maximize efficiency. The performance of the TMS is verified in a harsh flight profile. The selection of an appropriate return location and the storage of low-temperature fuel can enhance the efficiency of the fuel heat sink. An effective means of improving the vapor compression subsystem's efficiency is increasing the withstand temperature of the electronics. The introduction of LNG extends mission time by more than three times with minor fuel penalties. The potential for utilizing turbines to enhance LNG cooling efficiency is explored.

Improved design, development and field investigation of the wheel-soil interaction measurement system under aircraft load

This paper proposed the method and model to solve the issue of wheel-soil interaction on the soil runway and attained the equipment for measuring wheel-soil interaction and structural response by improving the design. Furthermore, through field tests, the research results show the characteristics of the three-direction force of the wheel on the soil runway under different tire loads and tire pressures, and present the mechanical response law of the soil runway structure under different soil strengths. In particular, it is found that the rolling resistance and rolling resistance coefficient of the wheel on the soil runway. Finally, the validity of the field test results is verified. This research lays a critical foundation for field testing on the load of aircraft and the formulation of a sophisticated wheel-soil interaction model, which has significant prospects for the structural design, the evaluation of the performance and life of soil runways.

К РАСЧЕТУ ПЛИТНЫХ АЭРОДРОМНЫХ ПОКРЫТИЙ ПРИ ИХ ВЗАИМОДЕЙСТВИИ С ИНЕРЦИОННОЙ НАГРУЗКОЙ ПРИ ДВИЖЕНИИ В РЕЖИМЕ ТОРМОЖЕНИЯ.

The method of calculating plates under the action of inertial loads during their movement with variable velocity is considered. The problem of the interaction of the airfield surface with the aircraft load is solved, at the moment of its movement, in braking mode, when landing on the surface in the form of an extended rectangular freely operable plate lying on an elastic base. When taking into account the nonlinear contacts of the chassis wheels with the plate, piecewise linear characteristics of contact stiffness are used. The vertical dynamics of the spatial model of the aircraft during the run is modeled by a system of rigid bodies with elastic-viscous bonds. To construct the methodology, the methods proposed earlier by the author of the article are used: a step-by-step method for solving problems of the relentless dynamics of structures and a method for calculating structures for the action of inertial and mobile force loads (the method of nodal accelerations).

Operational Analysis of an Axial and Solid Double-Pole Configuration in a Permanent Magnet Flux-Switching Generator

There are two main beneficial characteristics that doubly salient permanent magnet (PM) electrical machines present for aircraft applications: armature windings and PMs excitation sources placed on the stator side (maintenance and thermal management), and having a clear-cut rotor without PMs or excitation windings (vulnerable at high speeds due to associated centripetal mechanical stresses). Within this framework, a doubly salient permanent magnet (DSPM) generator was conceived by optimizing the stator size and rotor structure to minimize the torque ripple and maximize the root-mean-square (RMS) voltage value per turn of each generator phase. Firstly, a comparison between the 2D and 3D finite element method (FEM) models is made considering the results of 3D finite element analysis (FEA) as our benchmark in order to understand the accuracy of the 2D results against our benchmark model, the 3D one. A multi-objective design strategy based on a 2D FEA is made, it is set to have characteristics closest to optimal for a Boeing 767 turbine, that is, the necessary electromotive force for a required power of 90 kW at 3000 rpm, feeding a simplified Boeing 767 electrical power distribution system. The results show that the machine could not deliver the required power at 3000 rpm since the 2D FEA demonstrates that the 2D model gives optimistic results when compared with the 3D FEM model. However, with a 3D FEA of the machine feeding the aircraft load, it was seen that the machine’s efficiency is 92%, suggesting that this machine can be a plausible solution.

Mechanical response and numerical simulation of liquid soil abutment backfill

The application of a new liquid soil material and the treatment effect of backfilling an underpass tunnel in an airport are studied. The deformation and mechanical properties of liquid soil and conventional soil under load are comprehensively compared and analyzed via a numerical simulation with finite element software. The effects of the buried depth of overlying fill, tunnel height, and traffic load on the backfilling of liquid soil abutment are analyzed. The research results show that under the action of load, the overall deformation and stress distribution of the liquid soil and conventional soil show similar laws. However, liquid soil backfilling has great advantages over conventional soil backfilling in all aspects. Liquid soil backfilling can reduce the deformation and the compressive stress at the corner of the backfilling area by approximately 13% and 15%, respectively. The overburden buried depth has a great impact on the subgrade deformation. In the actual construction, the overburden buried depth should be 1.5 m. Overburden depth has a greater impact on the vertical deformation of the road, the self-weight of the overburden will act as an additional load on the overall roadbed, compared to conventional soil backfill, the overburden depth of 2.0 m conventional soil backfill overall deformation of the overburden depth is about equal to the overburden depth of 1.5 m liquid soil backfill, the use of liquid soil backfill is equivalent to the overburden fill to reduce the additional load of 0.5 m. The height of the box culvert has a greater impact on the stress, but this change is not linear, the actual construction in the case of meeting the specific requirements of use, should try to control in the vicinity of 8.4 m, and at the same time the use of liquid soil backfill can reduce the compressive stress of about 14%. The compressive stress increases first and then decreases with the increase in liquid soil modulus. The liquid soil modulus should be controlled to 180 MPa. Moreover, liquid soil backfilling can reduce the compressive stress in the backfilling area by approximately 25%. The trapezoidal slope of the backfill area is proportional to the deformation amount. Although an obvious correlation with compressive stress exists, the regularity is not strong. Thus, the trapezoidal slope should be set to 1:1 during construction. Traffic load slightly affects the overall deformation and compressive stress of the road. However, the distribution trend of deformation and stress changes obviously under the action of aircraft load. In the actual design, only one load form of aircraft load should be considered.

Advancing a major US airline’s practice in flight-level checked baggage prediction

Abstract In this paper, we aim to address a relevant estimation problem that aviation professionals encounter in their daily operations. Specifically, aircraft load planners require information on the expected number of checked bags for a flight several hours prior to its scheduled departure to properly palletize and load the aircraft. However, the checked baggage prediction problem has not been sufficiently studied in the literature, particularly at the flight level. Existing prediction approaches have not properly accounted for the different impacts of overestimating and underestimating checked baggage volumes on airline operations. Therefore, we propose a custom loss function, in the form of a piecewise quadratic function, which aligns with airline operations practice and utilizes machine learning algorithms to optimize checked baggage predictions incorporating the new loss function. We consider multiple linear regression, LightGBM, and XGBoost, as supervised learning algorithms. We apply our proposed methods to baggage data from a major airline and additional data from various US government agencies. We compare the performance of the three customized supervised learning algorithms. We find that the two gradient boosting methods (i.e., LightGBM and XGBoost) yield higher accuracy than the multiple linear regression; XGBoost outperforms LightGBM while LightGBM requires much less training time than XGBoost. We also investigate the performance of XGBoost on samples from different categories and provide insights for selecting an appropriate prediction algorithm to improve baggage prediction practices. Our modeling framework can be adapted to address other prediction challenges in aviation, such as predicting the number of standby passengers or no-shows.

Aircraft fleet optimization by the simplex method

The transport system efficiency and the quality of its operation is organically connected with the improvement of air transportation technical means on the basis of modern science and technology. One of the directions of further aviation transport system development is the creation of methodological basis for optimal aircraft operation. Therefore, the increase in aircraft efficiency is one of the important tasks, as its improvement is associated with savings in material and financial resources, which affects the fleet structure and the process of passenger traffic. The article is intended to substantiate the method of optimizing the use of airline aircraft by means of mathematical apparatus. It has been found that the mathematical model structure is required to form an optimal aircraft fleet. A variant of aircraft fleet formation has been proposed taking into account the mathematical model, built on the basis of linear programming, namely, using the simplex method. It has been determined that the choice of optimal aircraft options is greatly influenced by the value of the parametric series. To obtain a reliable result, the aircraft loading must be 100%, otherwise the error grows due to coefficients at unknown target function. The proposed method of determining the optimal fleet with different types of aircraft and air traffic routes, taking into account the conditions of their usage, allows to recommend airlines to use aircraft with the highest efficiency.

Advancements in base isolation for seismic mitigation: Perspectives on elastomeric and lead rubber bearings

Base isolation represents an environmentally sustainable and highly effective technique for mitigating structural responses to strong seismic forces generated by plate boundary tectonic activities. Its primary benefits include preventing structural collapse, minimizing property damage, and safeguarding human lives during severe earthquakes. This passive, energy-efficient approach is often complemented by supplementary dampers to further reduce seismic impact. This study provides a comprehensive overview of elastomeric and lead rubber isolators, covering their theoretical, experimental, and numerical aspects. The paper examines the seismic response of structures equipped with elastomeric and lead rubber bearings, including a discussion of their pros and cons. This paper presents the comparison of fixed base and rubber isolated base in SAP 2000 to assess the effectiveness of base isolation. Additionally, it presents findings from shaking table tests, relevant building codes, and practical applications, considering the impact of events beyond initial design parameters. The review delves into the historical evolution of elastomeric and lead rubber-bearing systems, offering valuable insights into their contemporary understanding. Furthermore, the paper introduces three-dimensional isolators designed to attenuate ground motion responses in both horizontal and vertical directions. It investigates the effects of soil-structure interaction and evaluates isolator responses under blast and impact aircraft loading conditions. Notably, specific types of bearings exhibit exceptional energy dissipation capabilities during catastrophic seismic events, leading to reduced floor acceleration and inter-storey sway at critical levels. In conclusion, the study offers future recommendations and identifies potential constraints in this field

Numerical analysis of influencing factors on wave load for an amphibious aircraft

Numerical method of wave load for an amphibious aircraft is carried out in this paper, and its effectiveness is verified by comparing with towing tank model test. It shows that at the same wavelength and speed, the aircraft’s wave load is positively correlated with the change of wave height, but with the increase of wavelength, the difference shows a gradually decrease. And wave load is positively correlated with the speed, the greater the speed, the greater the wave load is. The wave load decreases with the increase of the wavelength. The peak load generally occurs in the short wave state of 1.2 times the length of the fuselage. With the increase of the wavelength, the aircraft load gradually decreases.

Experimental Data-Driven approach for the evaluation of crack tip opening loads under variable amplitude loading

In this paper, we present a new data-driven approach for the evaluation of crack tip opening load (Pop) values under variable amplitude loading. These values are analysed for CT specimens manufactured from common aircraft grade aluminium alloys and subjected to several load sequences, all of which have a relatively high R-ratio content without significant overloads and underloads. Direct experimental measurements and outcomes of numerical simulations indicate that the Pop change abruptly from cycle to cycle. For this type of fatigue loading (including a military transport aircraft load spectrum with more than 400,000 turning points) and materials, it was found that Pop is well described by a linear function of the preceding minimum and maximum values of the applied loading. This finding provides a new simple way to evaluate the effective stress intensity factor range, which is often considered as a fatigue crack driving force. It is also verified via the use of machine learning that the proposed approach is capable of predicting the mean stress (R-ratio) effect on Pop for block loading. Therefore, the developed data-driven approach is a promising alternative to the computational methods, which currently dominate advanced fatigue life assessment procedures.

Deformation Control of Subway Tunnels Undercrossing Airport Facilities: A Case Study of the Xinzheng Airport Rail Transit Hub Project

The rapid expansion of urban areas due to China’s booming economy has led to a conflict between people and vehicular traffic. Consequently, rail transit, represented by subways, has become the primary mode of transportation for residents. However, the influence of soil damage on tunnel deformation is often overlooked in research on the safety of soft soil tunneling, leading to discrepancies between the results predicted by models and the actual settlement of tunnels. In this study, soil investigation and mechanical strength testing were carried out to analyze the impact of aircraft takeoff and landing activities on the Xinzheng Airport facilities. Damage variables are introduced into the Drucker‒Prager ideal elastic‒plastic criterion, and a soft soil tunneling model with soil deformation is established to investigate the spatial and temporal effects of the shield-cutting force, moving aircraft load, and tunnel deformation. Based on the synchronous grouting technique, a mechanical load-bearing system consisting of a concrete runway, solidified grout, and high-strength segments is formed to ensure the safety of flight activities.

ANALYSIS OF TAXIWAY PAVEMENT CONDITIONS WITH THE PAVEMENT CONDITION INDEX (PCI) METHOD AT JUANDA AIRPORT SURABAYA

Surabaya Juanda International Airport experiences an increase in aircraft transportation needs every year, where the increase results in reduced airside facility capabilities. The occurrence of some damage to taxiways N5N and N5S is caused by the temperature of the pavement reaching the soft point, the high groundwater level in the area, and aircraft loads that exceed capacity. This can interfere with flights that are about to take off and need to be analyzed regarding the level of damage and how to repair it. In analyzing damage to taxiway facilities can be planned with the Pavement Condition Index (PCI) method to determine the level of damage that occurs and can be used as a reference in maintenance efforts. Pavement maintenance uses guidelines from the regulation of the Director General of Civil Aviation Number: KP 94 of 2015 concerning Operational Technical Guidelines for Civil Aviation Safety Regulations. In analyzing pavement damage in taxiway N5N and N5S using the Pavement Condition Index (PCI) method, after obtaining the results of the analysis, then the repair method will be determined in accordance with the results of the analysis. The results of the analysis of Taxiway pavement conditions using the Pavement Condition index (PCI) method in the N5N and N5S taxiway areas at Juanda Airport Surabaya averaged 92.31. While the repair and maintenance methods in taxiway N5N and N5S are Patching and fogsealing. Furthermore, the estimated cost of the cost budget plan (RAB) for repairing damage with the patching and fog sealing method is IDR 13,918,200.00.