Joined-Wing Aeroelastic Design with Geometric Nonlinearity

Blair, Maxwell; Canfield, Robert A.; Roberts, Ronald W.

doi:10.2514/1.2199

“…Nowadays, attempts to design a joined wing airplane are more frequent, but in most cases researchers concentrate on the primary configuration of a joined wing airplane, with the front wing below the aft wing [3][4][5][6][7][8][9][10][11][12][13][14]. The previous experience of the authors [15] led to the conclusion that the joined wing airplane could fly much better in an upside down configuration.…”

Section: Introductionmentioning

confidence: 99%

Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

Sieradzki¹,

Dziubiński²,

Galiński³

2016

Archive of Mechanical Engineering

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The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtained numerically were compared with the performance of two classical configuration airplanes of similar category. Their computational fluid dynamics (CFD) models were created basing on available documentation, photographs and some inverse engineering methods. The analysis included simulations performed for a scale of 3-meter wingspan inverted joined wing demonstrator and also for real-scale manned airplanes. Therefore, the results of CFD calculations allowed us to assess the competitiveness of the presented concept, as compared to the most technologically advanced airplanes designed and manufactured to date. At the end of the paper, the areas where the inverted joined wing is better than conventional airplane were predicted and new research possibilities were described.

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“…Since the safety factor 1.5 is used, the allowable stress is reduced to 169MPa. (3) Stresses of all the elements except for the edge part should be less than the allowable stress, 169MPa. Lower and upper bounds of the design variables are set by 0.001016m and 0.3m, respectively.…”

Section: Formulationmentioning

confidence: 99%

Structural Optimization Using the Equivalent Load Concept

Park¹

2005

1

0

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Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. The joined-wing is a new concept of the airplane wing. The fore-wing and the aft-wing are joined together in a joined-wing. The range and loiter are longer than those of a conventional wing. The joined-wing can lead to increased aerodynamic performance and reduction of the structural weight. In this research, dynamic response optimization of a joined-wing is carried out by using equivalent static loads. Equivalent static loads are made to generate the same displacement field as the one from dynamic loads at each time step of dynamic analysis. The gust loads are considered as critical loading conditions and they dynamically act on the structure of the aircraft. It is difficult to identify the exact gust load profile. Therefore, the dynamic loads are assumed to be (1-cosine) function. Static response optimization is performed for the two cases. One uses the same design variable definition as dynamic response optimization. The other uses the thicknesses of all elements as design variables.

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“…The design data are adopted from a reference (4) and the data are used for the initial design of the later optimization process. Table 2 shows the results of the analyses.…”

Section: Geometric Nonlinearity Of the Joined-wingmentioning

confidence: 99%

“…(4) FSD is a non-gradient based algorithm that is used for resizing element thicknesses or areas so as to produce a design where each designed property is subjected to its maximum allowable stress. FSD provides a rapid means of performing initial sizing of aerospace vehicles and allows for the design of a virtually unlimited number of element sizes.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Response Optimization Using Equivalent Loads for a Joined-Wing

Park¹

2007

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Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. AbstractThe joined-wing is a new concept of the airplane wing. The fore-wing and the aft-wing are joined together in the joined-wing. The range and loiter are longer than those of a conventional wing. The joined-wing can lead to increased aerodynamic performances and reduction of the structural weight. The structural behavior of the joined-wing has a high geometric nonlinearity according to the external loads. The gust loads are the most critical loading conditions in the structural design of the joined-wing. The nonlinear behavior should be considered in the optimization of the joined-wing. It is well known that conventional nonlinear response optimization is extremely expensive; therefore, the conventional method is almost impossible to use in large scale structures such as the joined-wing.In this research, geometric nonlinear response optimization of a joined-wing is carried out by using equivalent loads. The utilized structure is a joined-wing that is currently being developed in the US Air Force Research Laboratories (AFRL).The joined-wing is modeled for finite element analysis (FEA). Equivalent loads are the load sets which generate the same response field in linear analysis as that from nonlinear analysis. In the equivalent loads method, the external loads are transformed to the equivalent loads (EL) for linear static analysis, and linear response optimization is carried out based on the EL. The design is updated by 3 the results of linear response optimization. Nonlinear analysis is carried out again and the process proceeds in a cyclic manner until the convergence criteria are satisfied. In other words, nonlinear response optimization is conducted by repeated use of linear response optimization. It has been verified that the equivalent loads method is equivalent to a gradient-based method; therefore, the solution is the same as that of exact nonlinear response optimization.

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Joined-Wing Aeroelastic Design with Geometric Nonlinearity

Cited by 79 publications

References 12 publications

Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

Structural Optimization Using the Equivalent Load Concept

Nonlinear Response Optimization Using Equivalent Loads for a Joined-Wing

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