Center Wing Research Articles

High-speed multi-camera videogrammetric measurement of full-field 3D motion and deformation in full-scale crash testing of typical civil aircraft

Crashworthiness has been and will continue to be the main concern in aircraft design. Crash tests are essential approaches to investigate the crashworthiness of civil aircraft. Videogrammetric methods have been employed in crash tests to overcome the disadvantages of laborious, time-consuming measurement data collection using contact sensors. However, previous methods using a single pair of cameras still face challenges in large-scale applications due to the inherent contradiction between measurement range and accuracy. In this paper, a videogrammetric method using four high-speed cameras is proposed to measure the full-field three-dimensional (3D) dynamic deformation for evaluating the impact response characteristics of the full-scale crash test aircraft. Increasing the number of high-speed cameras not only can enhance the resolution and then measurement accuracy of object, but also expands the measurement range significantly. To ensure the performance of digital image correlation (DIC) used for large-scale measurement range, a speckle pattern optimization design and fabrication method is presented to generate the random speckle with uniform spraying size and density. A global calibration method based on the high-precision total station is proposed to unify the data of different stereovision subsystems. The implementation of the proposed method is illustrated through a 6.0 m/s full-scale crash test using a civil aircraft approximately 24 m in length. The impact velocity, full-field displacement and strain of the fuselage structure are measured. The results show that the test data are complete and reliable. After the vertical crash at 5.71 m/s, the lower structure of the cabin floor is seriously deformed, and the upper structure of the fuselage in the central wing area is obviously deformed due to the inertia effect of the wing. The stiffness difference of the different fuselage segments results in significant differences in dynamic response. The higher the stiffness is, the smaller the deformation. This work may provide some valuable technical insights that could support the crashworthy design, verification, and certification of civil aircraft.

Studying the quantitative heterogeneity between two populations of Culex pipiens in two Iraqi provinces

The objective of this study was to investigate the quantitative heterogeneity between two populations of Culex pipiens (a mosquito species) and understand the underlying reasons for this variability. The study focused on two specific areas viz. Diyala and Alnajaf. To achieve this, the Geometric Morphometric Technique was employed using C. pipiens female wings. The principal components of the wings were analyzed, the central size of each female wing was calculated, and samples from both populations were compared using discriminant analysis based on wing size. The statistical analysis, including T-tests, revealed no statistically significant differences in the central wing size between the two studied areas. Additionally, an ANOVA analysis indicated that there were no significant differences in wing shape and size among the female insects from Diyala and Alnajaf. In summary, the study found that the central wing size and wing characteristics of female C. pipiens mosquitoes were similar across the Diyala and Alnajaf regions.

Experimental Propeller Performance Analysis of Distributed, Single and Isolated configurations

Distributed propulsion (DP) configurations are a promising concept for future aircraft systems. The main objective of the presented experiment is to investigate aerodynamic interactions of such configurations in detail and compare DP results to a single propeller configuration. The experimental setup at the Propulsion Test Facility, TU Braunschweig, features three co-rotating propellers. These are not attached directly to the wing, but are mounted on a separate carrier. This decoupling allows the forces and moments acting on wing and propeller to be considered separately. Additionally, different relative propeller positions are set up easily. In order to eliminate side wall effects, only the centre propeller and the centre wing element are subject of investigation for the distributed configuration. The periodically repeating outboard propellers reduce the wind tunnel interference while providing a true DP setup for the instrumented centre. Additionally to the DP setup, tests for conventional propeller wing configurations (only centre propeller installed) as well as isolated propeller and clean wing tests were performed. Thus, the DP effects on wing and propeller and the effect of the downstream wing on the propeller are clearly identified. The comparison between single propeller and distributed propulsion configurations shows that with distributed propulsion the drag increase is reduced from 326% to 216% compared to a clean wing. This effect is intensified by a greater thrust level and higher angles of attack. In order to identify the distributed propulsion effects, the forces acting on the propeller as well as the resulting efficiency of the propeller are compared between the distributed and single propeller configuration for two different relative propeller positions. The efficiency of the centre propeller is increased due to the outer propellers by approx. 2% to 3%.

Икона в лесу. Религиозно-культурные перемены на польско-руськом средневековом пограничье в свете новых археологических находок

The authors examine a stray find of two Early Rus’ miniature copper alloy icons of the middle — second half of the 13 th century found in a broad historical and cultural context in Eastern Poland. One of them is the central wing of a triptych with the image of the Mother of God Hodegetria and a Medusa Gorgon composition on the back. The other icon, also depicting the Hodegetria and the Child with an unfolded scroll, is extremely unique. This iconographic type is characteristic of Southern Italy. The icon itself can copy an unpreserved large-sized icon from Kyiv. The icons were hidden in an uninhabited space in forest no later than in the 14 th century. This corresponds to the archaic rituals of concealing unused sacred objects due to their worn and torn state or changes in the cultural situation. The article provides an overview of sacred objects found in Central-Eastern Europe in a similar context — in forest or on trees. Water was another element intended to conceal sacred objects. The authors substantiate the hypothesis that the lead pilgrimage badges found in Western Europe in rivers or in a wet context were also deposited there in accordance with the archaic rituals of “floating on water” due to religious changes at the turn of the 15 th—16 th centuries. The concealment of icons in the forest was associated with the entry of the Rus’-Polish borderlands into the Kingdom of Poland and subsequent transformations of the local Orthodox culture.

КОНЦЕПЦІЯ ЗБЕРЕЖЕННЯ АРХІТЕКТУРНОЇ СПАДЩИНИ НА ПРИКЛАДІ МІСТА ОДЕСА

The article briefly discusses the concept of preservation of architectural monuments in the country and the current state and development trends in the modern world of historical hotels, namely located in architectural monuments and historical buildings, which form the historical record and attractiveness of the city. The effectiveness of the functioning of the Association of Historic Hotels is based on a combination of two factors - the unconditional appeal of living directly in a historical place (building), getting to know its unique color as if from the inside and, at the same time, having the opportunity to experience all the advantages of staying in a high-class hotel. The project of creating a national hotel association on the basis of historical and cultural monuments has the main goal - the revival and preservation of the national cultural tradition by means of its adaptation to modern socio-economic conditions and is possible according to European examples. The planning possibilities of the historical quarters of Odessa with perimeter buildings allow for renewal and reconstruction with the tactful inclusion of new elements, re-planning and increasing the technical and economic indicators of the side wings and inner quarter space, while preserving the highly artistic facade of the central wing along the red line of the building. A historical hotel is an active vital part of the city, as an element of the urban planning system and under the condition of appropriate operation and functional content, the presence of a modern level of comfort, it can have an important socio-cultural and economic significance in the structure of modern development, preserving its historical architectural forms, the general compositional the spatial value of the historical buildings of the city.

Housing for the Elderly

The banking family Emma and Henry Budge established their foundation in Frankfurt, Germany, as a civic initiative, aiming to build a contemporary, modern residential home for the elderly. Under the direction of Ernst May, appointed as city architect in 1925, the City of Frankfurt announced a unique competition in 1928 as part of its program Das neue Frankfurt: A retirement home for Jewish and Christian residents, primarily for people of the “educated middle class”. Architects Mart Stam, Werner Moser, and Ferdinand Kramer, members of the planning team Das neue Franfurt, won this competition with their innovative contribution. From 1928 to 1930, they realized a type of housing for the elderly that was exemplary for its time and for later retirement homes.Via Mart Stam, this project flowed into the teaching of the Bauhaus construction department in 1928-1929. On behalf of Mart Stam, Ella Bergmann-Michel produced the famous documentary film about the home Where do Old People Live? in 1930-1931.Special quality features of the two-story housing complex with 100 apartments were the interesting typology, the very consistent architectural language, colorfully designed, light-flooded rooms aligned along large common garden courtyards, and common areas as a social and architectural center. Equally remarkable were the iron skeleton construction in the central wing, the bulkhead construction method using prefabricated elements as partition walls between the rooms, and the cost and construction time savings due to the rational construction technology.Under the growing influence of the National Socialists and after the expulsion of Ernst May and his Frankfurt team, the denunciation of the social commitment and a propagandistic denigration of NEUES BAUEN, designing Modern Movement architecture, took place in an infamous way. At the same time, the National Socialists showed the buildings to foreign visitors as their achievement.After the destruction during the war, the building was used as a hospital for the U.S. Army.A very exemplary renovation of the ensemble was carried out in 2001-2002, planned by Dirk Hoppe Architects from Darmstadt, Germany, with the participation of the State Office for the Preservation of Historical Monuments, Dr. Christoph Mohr, the expertise and advice in preserving historical monuments of Prof. Dipl.-Ing. Ruggero Tropeano, Zurich. With minor changes in detail, for example, in the building services and the accessible design of the rooms, the continuity of use as a high-quality retirement home was restored, and this valuable example of modernist architecture was secured. An example of BEST PRACTICE.

Notational Analysis on Goal Scoring and Comparison in Two of the Most Important Soccer Leagues: Spanish La Liga and English Premier League

Goals scored are the most important performance indicator and may be a good tool to analyze game style predominance within different leagues. The aims of this study are to describe how goals are scored in the two major soccer leagues in the season of 2020/21, and to compare both leagues to watch possible differences in the offensive sequences that lead to goal-scoring. The aims of this study were: to evaluate goal scoring trends among two main soccer leagues and to compare the two leagues. A total of 1409 goals were observed using notational analysis. The total results show a dominance of positional play/fast attack (n = 38%), followed by set pieces as the second means to score (n = 32%) with corner kicks having a great impact (n = 36%) within set pieces goals. The most goals were scored by short possessions (n = 50%) with short passes number (n = 57%), with the recovery of the ball in the offensive third (n = 47%) and the huge dominance of finalization in central areas inside the box (n = 78%). Spanish La Liga scored more by positional play/fast attack, with most of the possessions starting in the medium third and using more the “central wing goal area” and “between wings left in the box” end zones when compared with English Premier League. The latter has more goals from counterattacks and corner kicks with very long possessions. Most of the possessions start in the offensive third and more goals are scored in “central wing between penalty and goal area” in comparison with Spanish La Liga. Coaches must be aware of the trends of the game and of the differences across leagues to prepare themselves when working in different countries to each specific characteristic.

Spór Hilarego Szpilowskiego ze Stanisławem Zawadzkim przy budowie koszar w Kamieńcu Podolskim – uwagi inżyniera budownictwa

Kamieniec Podolski was the most important fortress of the Polish Republic, defending its southeastern border. Unfortunately, there were no barracks for soldiers in the fortress. Therefore, in the 1780s, their construction began. The project of Jan de Witte, an experienced and distinguished fortifier of the Kamieniec fortress, was rejected, and a new project was commissioned to a young but talented designer, Stanisław Zawadzki (1743–1806). He designed a five-wing building on a square plan, with a central wing that divided the interior into two courtyards. The building was first approved by the Polish king, Stanisław August Poniatowski, and only then they began to look for a site where it could be built. Unfortunately, it was not possible to find a suitable site, which was the reason for changing the location of the barracks several times. The construction of the barracks was entrusted to Hilary Szpilowski (1753–1827), who found many errors in the project. Zawadzki’s rare visits made necessary consultations impossible and forced Szpilowski to take independent decisions regarding changes in the building design. The Committee of the Military Department of the Perpetual Council rejected all of Szpilowski’s allegations. In this article, a detailed analysis of the solutions introduced at that time was carried out based on the preserved site maps and design drawings. It was shown that the project contained serious errors, especially the mismatch with the existing terrain, which generated a gigantic scope of earthworks, a lack of water supply and sewage disposal, and the lack of a tie beam reinforcing the building. Therefore, contrary to the opinion of the Committee of the Military Department of the Perpetual Council, the entire blame for the poorly designed barracks building and the resulting problems during construction should be placed on Stanisław Zawadzki, not Hilary Szpilowski.

Effects of Cryogenically Treated CFRP Composite on the Buckling Behavior in the Adhesively Bonded Beam

Carbon fiber reinforced plastic (CFRP) composite materials have favorable mechanical and physical properties such as low density, high strength-to-weight ratio, high fatigue resistance and high creep behavior, and high stiffness. Thanks to these unique properties, they produce aircraft parts such as outer flaps, carry-through structures, and center wing boxes and automotive parts such as body panels, engine components, and structure members. However, studies have been continuously performed on improving the properties of CFRP composite materials. Recently, investigation of the effects of cryogenic (LN2) cooling on the mechanical behavior and characteristic of these composite materials is getting a popular and important issue. In this sense, this study aims to examine the buckling behaviors of adhesively bonded beam-produced cryogenically treated carbon fiber reinforced plastic (Cryo-CFRP), CFRP, steel, and aluminum. Therefore, a new finite element model was adopted to evaluate the buckling capacity of Cryo-CFRP composite material in the adhesively bonded beam. The model is a supported adhesive beam subject to two opposite-edge compressions until the material buckles. The elastic, homogeneous adhesive was used in the assembly. Finite element models for the adhesively bonded beam having four different adherents (CRFP, Cryo-CFRP, steel, and aluminum) were established by ANSYS® software. The critical buckling loads of the adhesively bonded beam were predicted, and their mode shapes were presented for the first six modes. The effects of the usage of Cryo-CFRP on the critical buckling load were investigated. Among the adherents’ materials, the highest critical buckling load was determined for Cryo-CFRP/Steel adhesively bonded beam as 23.6 N. This value was obtained as 22.3 N for CFRP/Steel adherent samples. Thus, the critical buckling load was increased by 5.6 % when one adherent steel was constant and the other adherent material changed from CFRP to Cryo-CFRP. Also, the critical buckling load increased by 3.7 % when using a cryogenically treated Cryo-CFRP/Aluminum couple instead of a CFRP/Aluminum couple in the sandwich beam. The findings demonstrated that the cryogenic treatment positively affects the buckling behavior in the adhesively bonded beam.

Investigation and Design of the Transonic Laminar Flow Characteristics in a Laminar Aircraft

Reducing drag is critical to aircraft design. In recent years, laminar technology has become one of the most important feasible technologies for civil aircraft drag reduction design under many design constraints. However, various factors have a certain impact on the laminar flow characteristics in the state of transonic flight. Therefore, it is necessary to deeply understand the specific effects of various flight parameters on the characteristics of laminar flow. In this paper, a parameter sensitivity analysis for a central experimental wing in a special layout aircraft was carried out to investigate its transonic laminar characteristics. Then, the airfoil of the central experimental wing of the aircraft was designed for real flight. The RANS (Reynold-averaged Navier–Stokes) method combined with the γ−Reθ transition model based on local variables was used. The computational approach was validated by the wind tunnel tests and analyzed by the grid independence analysis. The sensitivity mainly focuses on the transition location and the length of the laminar flow zone of the central experiment under different boundary conditions. The transonic transition was affected by a variety of interacting factors that include FSTI (free stream turbulence intensity), pressure gradient, Re (Reynolds number), Ma (Mach number) and α (angle of attack, degree). The essence of the transition is the disruption of flow stability caused by the increase in flow entropy. Among these factors, FSTI directly affects global flow stability, and the pressure gradient affects local flow stability. Ma and α can indirectly affect the flow stability by changing the pressure gradient. Re can control the boundary layer properties to change the flow stability, whereas its effect is easily determined by the pressure gradient. Finally, the improved design of the airfoil with the central experimental wing was conducted. The design of weak shock wave and aerodynamic load on the rear part of the airfoil can improve the aerodynamic characteristics (CL, lift coefficient, increases by 0.28) of the airfoil, which can reduce the load burden on the outboard wing without affecting the laminar flow characteristics of the airfoil. In the next step, cross-flow instability will be considered.

Analysis of the influence of day and night temperature difference on oxygen concentration in ullage space of fuel tank

PurposeDetermining the variation law of the oxygen concentration in the ullage space of the fuel tank is the key to the design of the inert system. Among various factors affecting the oxygen concentration in the ullage space of the fuel tank, the temperature difference between day and night shows particular importance while relevant analysis and calculation are scarce.Design/methodology/approachThis study establishes a theoretical simulation model of the central wing fuel tank of an aircraft according to the relevant provisions of day-night temperature variation in FAR25 airworthiness regulations, verifies the model with the existing experimental data and discusses the corresponding relationship between the oxygen concentration in the ullage space of the fuel tank and the day-night temperature difference. The influence of day and night temperature difference, fuel type, fuel load rate, initial oxygen concentration, dissolved oxygen evolution and other factors on the oxygen concentration in the ullage space of the fuel tank were analyzed, and the limit of initial oxygen concentration of the fuel tank before the shutdown at night meeting the requirements of the airworthiness provisions was proposed.FindingsThe results show that the temperature difference between day and night, fuel load rate, initial oxygen concentration and other factors have different effects on the oxygen concentration in the ullage space of fuel tank. The initial oxygen concentration limit before shutdown shall be 2% below the 12% oxygen concentration stipulated by FAA.Research limitations/implicationsThe research results in this paper will be of good reference value to the design of the inert system and the calculation of the flammability exposure evaluation time. This paper aims to be good reference of the design of the inert system and the calculation of the flammability exposure evaluation time.Originality/valueThe research results of this paper can provide practical guidance for the current civil airworthiness certification work.

COCOPLOT: COlor COllapsed PLOTting software Using colour to view 3D data as a 2D image

ABSTRACT Most modern solar observatories deliver data products formatted as 3D spatiotemporal data cubes, that contain additional, higher dimensions with spectral and/or polarimetric information. This multidimensional complexity presents a major challenge when browsing for features of interest in several dimensions simultaneously. We developed the COlor COllapsed PLOTting (COCOPLOT) software as a quick-look and context image software, to convey spectral profile or time evolution from all the spatial pixels (x, y) in a 3D [nx, ny, nλ] or [nx, ny, nt] data cube as a single image, using colour. This can avoid the need to scan through many wavelengths, creating difference and composite images when searching for signals satisfying multiple criteria. Filters are generated for the red, green, and blue channels by selecting values of interest to highlight in each channel, and their weightings. These filters are combined with the data cube over the third dimension axis to produce an nx × ny × 3 cube displayed as one true colour image. Some use cases are presented for data from the Swedish 1-m Solar Telescope and Interface Region Imaging Spectrograph, including H α solar flare data, a comparison with k-means clustering for identifying asymmetries in the Ca ii K line and off-limb coronal rain in IRIS C ii slit-jaw images. These illustrate identification by colour alone using COCOPLOT of locations including line wing or central enhancement, broadening, wing absorption, and sites with intermittent flows or time-persistent features. COCOPLOT is publicly available in both idl and python.

Dynamic Testing in Support of the Seismic Assessment of a Century Old Masonry Building Complex

The vulnerability assessment of existing masonry buildings is a largely investigated research topic with some aspects still to be faced. In historic towns, masonry buildings are aggregated and together confined, and their final appearance is derived from interventions and additions during their lives in different times and with different masonry textures or different construction materials. Demolitions and reconstructions of some parts were frequent, with the difficulty of now understanding the effectiveness of the mutual constraints. The seismic assessment of a case study of a 175-year-old building complex in Udine (Italy) provides an opportunity to use the results of ambient vibration tests to face the problem of modelling aggregate buildings for their seismic assessment. The “Padiglione Lodi” building complex was built in 1847 and extended and renovated several times afterwards. It was built mostly using URM with limited use of reinforced concrete. It consists of a main building and three wings (western, central and eastern). The inspections, experimental survey and analysis of the available documentation are used to suitably calibrate a Finite Element Model of the whole complex. Moreover, this allows the singling out of the central wing, as the unit needs more careful investigation. Non-destructive dynamic testing is then applied to the central wing in order to further validate the model and improve the knowledge of the interaction of the unit with the rest of the building. General remarks on the effective application of non-destructive dynamic analysis in conjunction with other methods to the seismic assessment of large URM building complexes are drawn.

Use of the parachute system for the collective rescue of passengers and aircraft crew

This study covers the issues of the security system in civil aviation. The relevance of the topic is conditioned by a qualitatively new approach to the design of civil aviation, since the modern equipment has the means intended for rescue directly in the area of contact of an emergency aircraft with the ground. When hitting the ground, as a rule, the lower part of the airframe is crushed, the fuselages break in the centre wing section, and the interior equipment breaking off is very traumatic to passengers, the engines are extremely fire and explosion dangerous, which leads to an emergency situation developing into a catastrophic one. The purpose of the study is to investigate the existing security system of a civil aircraft and develop the modification of aviation equipment with the help of collective rescue systems. Two main areas of application of collective rescue systems in aviation technology are analysed. As a solution to the problem at hand, a modification in the form of a parachute system of collective rescue is proposed. A detailed description of the system operation with the use of the necessary calculations for weight, aerodynamic and similar costs is given. The system under study relates to aviation technology and can be used in the development of transport (passenger, cargo, business class, etc.) aircraft. The proposed modification would significantly increase the level of flight safety due to a preventive measure that would exclude the contact area of the emergency aircraft with the ground.

АНАЛІЗ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ ФІТИНГОВОГО СТИКУ ПАНЕЛЕЙ ВІД'ЄМНОЇ ЧАСТИНИ КРИЛА ТА ЦЕНТРОПЛАНА ТРАНСПОРТНОГО ЛІТАКА

Fitting joints are widely used in aircraft structures, and they are responsible for the interconnection of important components. The stress-strain state analysis of the fitting joint must be carried out before the performance analysis of the fitting joint. With the help of 3D modeling software (CATIA) and finite element analysis software (ANSYS), the stress-strain state of each component in the fitting joint of outer wing section was calculated in this paper. In the CATIA, the solid model is simplified and segmented according to the size of the cross section and the height of the center of gravity of the model. In the ANSYS, the beam elements are used to replace the simplified segmented model to obtain the internal force distribution of the solid model and to determine the magnitude and change law of the stress applied to the end of the solid model. When calculating the force transmitted by the fastener, the pre-tightening force of the bolt and the interaction between the surfaces of the component are taken into account, so as to simulate the real force situation well. Therefore, it is a very feasible method to use the CATIA and ANSYS to obtain the stress-strain state of components in the fitting joint of center wing section and outer wing section.The results show that under the working conditions of the fitting joint (130Mpa), the fitting of outer wing section with center section has a maximum stress of 245.79Mpa and a maximum strain of 0.0035, the stringer of outer wing section has a maximum stress of 293.17Mpa and a maximum strain of 0.0047, the lower panel of outer wing section has a maximum stress of 289.53Mpa and a maximum strain of 0.0042. The connecting bolts (M8 and M6) have a maximum stress of 686.81Mpa and a maximum strain of 0.0063, which meets the design requirements. In addition, according to the analysis results of the stress-strain state of the fitting joint of outer wing section, the force distribution of the bolts in the fitting joint of outer wing section with center section was obtained in this paper. It has been confirmed that due to the different positions and force areas of the bolts, the force distribution between rows of bolts is uneven, and the first row of bolts has a more force.

Prionosciadium guzmanianum (Apiaceae, Apioideae), a new species with red flowers from western Mexico

Prionosciadium guzmanianum, a second species of Prionosciadium with red flowers is described and illustrated. The genus is almost endemic to the Mexican Republic and presents a high richness and endemism in western Mexico. Given the color of its flowers, the closest relationship of the new species is with P. tamayoi, from which it differs by the basal, ternate‐pinnatifid leaves, pinnatifid leaflets and larger orbicular fruits with central dorsal rib wing. Pollen grains are described and illustrated, and information on the habitat of the species is provided.

Effect of using the additional field player on attack efficiency during 2017 Women's Handball World Championship

Background: Rule changes such as the use of the additional field player in the attack to replace the goalkeeper can significantly change the tactical strategies of the handball game. Objective: The aim of this study was to analyze the effectiveness of the use of the additional field player in offensive situations during the positional attack and counterattack suffered by the teams participating in the 2017 Women's Handball World Championship. Methods: The sample consisted of 15 matches in the knockout stage. In total, 1638 attack actions (positioned and counterattack) were identified and analyzed. For the exploratory analysis, we used descriptive statistics, obtaining the frequencies and respective percentages for each category of study variables for both situations: when the additional player was used and when not. Results: Our data showed that teams tend to use goalkeeper substitution by a field player to maintain numerical equality (54.9%), followed by the use to obtain numerical offensive advantage (41.3%). There were no differences in the throwing position (left wing, left back, center, pivot, right back and right wing) between situations with and without the additional field player. There was a significant increase in the number of errors when using the additional field player to gain numerical superiority in attack. In numerical equality and inferiority situations, no difference was found. The analyses also showed more counterattacks with goals and 9-m throws when using the additional field player. Conclusions: The use of the additional player did not bring advantages to the team, as more counterattacks were suffered.

Design of the stringer end of the composite centre wing lower panel in the plug-in butt joint form

The outer wing and the central wing of the aircraft are butted at the wing root through rib 1. The load transfer in the connection zone of the wing root is complex. In the plug-in butt form, additional bending moment will be generated, which is the most prone to damage. Based on the analysis of the force transmission in the butt joint area of the wing root, combined with the test data, this paper proves that the main failure mode of the composite central wing lower panel is the delamination failure of the stringer web at the end, and suggestions for optimal design are proposed.

Correlation of CFRP and AA7075 Aircraft Wing box structure using FEM

Composite materials are becoming more important in the construction of Mechanical structures. The primary objective of this paper is to analyse the Carbon Fibre Reinforced Plastic (CFRP) and Aluminium alloy (AA 7075) aircraft wing box using finite element method. Both results has been correlated. Both CFRP and AA7075 structures modelling and numerical simulations were executed at various loading conditions. The deformed configuration of the CFRP and AA7075 aircraft wing box along with stress plot have been computed using analysis. Based on these studies, the CFRP and AA7075 central wing box, representing a weight saving of up to one and a half tonnes compared to the most advanced aluminium alloys. The results also expose the increasing strength with reduced weight.

Analysis of crack length and life flight cycle in center wing lower surface skin access hole aircraft with DCRACK software

One of the problems in the aviation world is that accidents are increasing. The increase in incidents and accidents can be caused by several factors including human error, weather conditions, and failure of the structure / component of the aircraft. Accidents that occur from failure factors, one of which is caused by cracks that occur in the structure due to continuous loading which does not become more attention until the failure. In this final project an analysis of damage tolerance is carried out at the Wing Centre, Lower Surface and Skin Access Hole locations. The choice of location is because aircraft wings are the most important component in aircraft control while operating. Damage tolerance analysis is carried out as an effort to minimize failures in aircraft structures due to cracks that arise. Damage tolerance analysis is done by giving load in the form of an aircraft wing, then an analysis of the growth of crack length that occurs due to loading. The result of damage tolerance analysis will be obtained crack length, aircraft flight life cycle, and critical crack value. And in this study will also bring up a recommendation that is the right time to do the inspection interval.