# Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

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## Abstract

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## 1. Introduction

- Global parameterization of airframe structure on the base of common special four-level database.
- Four-level nested FE models according to detailing of the structure.
- Full automation of initial data definition and analysis of calculations results.
- Parallel solving strength tasks on both nested FE models and auxiliary analytical strength models.
- Standard format of input and output data.

## 2. Airframe Strength Analysis within FLA

## 3. Parametrical Auxiliary Aerodynamic Model for FLA

- Building of surfaces of fuselage crossing,
- Building of lifting surfaces of wing and empennage,
- Building of “bridges” for correct fluid motion,
- Building of surfaces of cowlings and pylons,
- Setting of control surfaces from range of lifting surfaces.

- Structure,
- Fuel,
- Payload,
- Equipment and facility,
- Power unit,
- Landing gear.

## 4. Validation of SAPAM within the FLA

## 5. Validation of the Modified FLA as a Part of Design Procedure

## 6. Time Efficiency of the FLA of Strength Analysis

## 7. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 3.**Block scheme of the four-level airframe strength models decomposition in strength analysis.

**Figure 4.**General view of simplified auxiliary parametrical aerodynamic model (SAPAM) of an aircraft.

**Figure 16.**The scheme of searching of the wing-design load cases on the base of simple analytic beam model.

**Figure 17.**Ultimate bending and torsion moments and shearing forces for three variants of wing aspect ratio.

Parameter | Value |
---|---|

Maximum altitude, m | 10,250 |

Maximum speed, km/h | 500 |

Maximum Mach number | 0.445 |

Maximum dynamic pressure, kgf/m^{2} | 1120 |

Altitude at start of cruising, m | 7200 |

Cruise speed, km/h | 400 |

Cruise Mach number | 0.36 |

Maximum Take of Weight, kg | 15,000 |

Maximum landing weight, kg | 13,775 |

Payload, kg | 2750 |

Fuel weight (with maximum payload), kg | 2750 |

Minimum flight weight, kg | 12,025 |

Maximum front gravity center, m | 7.93 |

Maximum aft gravity center, m | 8.155 |

Wingspan, m | 26.1 |

Wing square, m^{2} | 58 |

Fuselage length, m | 19.9 |

Wing Aspect ratio | 11.7 |

Property | Value |
---|---|

Young modulus, Pa | 7.2 × 10^{10} |

Poison ratio | 0.3 |

Shear modulus, Pa | 2.76 × 10^{10} |

Allowable tensile stress, Pa | 3.6 × 10^{8} |

Allowable compress stress, Pa | 4 × 10^{8} |

Allowable shear stress, Pa | 2.05 × 10^{8} |

Density, kg/m^{3} | 2750 |

Case ID | Dynamic Pressure, kgf/mm^{2} | Ny | Mach |
---|---|---|---|

LC1 | 1100 | 2.5 | 0.45 |

LC2 | 324 | 2.5 | 0.212 |

LC3 | 1100 | −1 | 0.45 |

LC4 | 324 | −1 | 0.212 |

**Table 4.**Weight characteristics of wing, with and without strut, compared to base variant without strut.

Variant | Wing Aspect Ratio | m/m_{0} without Strut, % | m/m_{0} c with Strut, % |
---|---|---|---|

Base | 11.7 | 100 | 87.7 |

1 | 15 | 134 | 93.3 |

2 | 20 | 183 | 116.5 |

**Table 5.**Analysis of labor intensiveness of strength analysis of regional aircraft airframe structure.

Operations | The Base FLA | The Modified FLA | Labor Saving (Time) |
---|---|---|---|

Initial data definition, work hours | 80 | 4 | ≥20 |

Model validation, work hours | 16 | 2 | ≥8 |

Analysis, work hours | 112 | 4 | ≥28 |

Post-processing, work hours | 32 | 2 | ≥16 |

Total, work hours | 240 | 12 | ≥20 |

Finite Element Size, m | ≤0.5 | ≤0.4 | ≤0.3 | ≤0.2 | ≤0.1 |
---|---|---|---|---|---|

Error, strain energy of FEM model, % | 11.6 | 7.6 | 5.3 | 3.9 | 2.1 |

Amount of nodes | 9000 | 16,000 | 28,000 | 40,000 | 112,000 |

Memory, Gb | 0.75 | 1.1 | 2.2 | 4 | 9.6 |

Time of FEM model generation, s | 0.07 | 0.1 | 0.6 | 1.1 | 4.3 |

Nastran simulation time, s | 16 | 23 | 48 | 114 | 480 |

Reading the results of simulations, s | 0.3 | 0.61 | 2.2 | 4.3 | 9.63 |

Buckling analysis, s | 5 | 5 | 5 | 5 | 5 |

Calculation of weight and strength reserves, s | 0.13 | 0.5 | 1.2 | 6.3 | 12.4 |

Total time of iteration, s | 21.5 | 29.21 | 57 | 130.7 | 511.33 |

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**MDPI and ACS Style**

Vedernikov, D.V.; Shanygin, A.N.; Mirgorodsky, Y.S.; Levchenkov, M.D.
Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models. *Aerospace* **2021**, *8*, 80.
https://doi.org/10.3390/aerospace8030080

**AMA Style**

Vedernikov DV, Shanygin AN, Mirgorodsky YS, Levchenkov MD.
Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models. *Aerospace*. 2021; 8(3):80.
https://doi.org/10.3390/aerospace8030080

**Chicago/Turabian Style**

Vedernikov, Dmitry V., Alexander N. Shanygin, Yury S. Mirgorodsky, and Mikhail D. Levchenkov.
2021. "Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models" *Aerospace* 8, no. 3: 80.
https://doi.org/10.3390/aerospace8030080