Plane symmetric aircraft hang-off load calculation and strength check method

Abstract

The invention relates to a plane symmetric aircraft hang-off load calculation and strength check method, which comprises the following two steps: 1, giving basic equation sets of inertia, aerodynamicload and hang-point load in a vector operation form to obtain an initial solution and a final solution of the hang-point load so as to avoid tedious judgment of coefficient symbols in the traditionalmethod; and 2, according to the hanging point load obtained in the step 1, establishing a high-precision strength checking method for a structural lifting lug and presser foot point area, and checkingthe strength of the lifting lug and presser foot point area. The invention provides a method for accurately applying the local load and reasonably evaluating the result, and the accuracy of the method for checking the lug and presser foot areas is superior to that of the traditional method.

Description

technical field [0001] The invention relates to a method for calculating and checking the flying load of a plane-symmetrical aircraft and belonging to the field of load and strength design, and is used for calculating the flying load and checking the structural strength of a plane-symmetrical aircraft (suspended objects). Background technique [0002] Airborne suspended objects are generally connected to the aircraft through a pylon. The hanging object and the hanger are generally connected by a hook / hanging lug and an anti-swing stopper. The hanging object generally adopts the general structure of tandem lifting lugs and anti-swing stopper, and is connected with the hook of the hanger and the presser foot of the anti-swing stopper through two lifting lugs and four presser foot points. Wherein, the two lifting lugs are located on the longitudinal symmetrical plane of the upper surface of the suspended object, and the four presser foot points are divided into two groups, fro...

AI Technical Summary

Problems solved by technology

However, for plane-symmetric aircraft, the main problems of the above-mentioned standards are: (1) the aerodynamic force is given in the form of the center of pressure and the three-way force, and the surface-symmetric suspension has no axis of symmetry, and there is no precise expression for the center of pressure; (2) " The hanging point load expression of GJB540.5-1988" is only applicable to the case where the longitudinal coordinates of the center of mass are between the hanging points and the lateral coordinates are between the presser feet, while "MIL-A-8591H" and "GJB1C-2006" The expression of the hanging point force can be applied to different topological relationships between the center of mass and the location of the hanging point, and the sign of the distance between the hanging point and the center of mass needs to be judged, resulting in cumbersome logic; (3) "MIL-A-8591H" and "GJB1C-2006" give The formula for the load coefficient of the suspended mass center is incorrectly given in the form of the acceleration of the carrier aircraft plus the relative acceleration, but should be given in the form of the apparent acceleration plus the relative acceleration, resulting in the load coefficient in the vertical direction 1g less than the actual value; (4) When "GJB1C-2006" carries out adaptive modification of the coordinate system on the basis of "MIL-A-8591H" (from MIL's x rear y right z upper coordinate system to GBJ's x front y When going to the z right coordinate system), only the coordinates y and z are exchanged, and the x direction is not reversed, resulting in an error in the calculation result of the hanging point load

Traditionally, the strength check of the lifting lug and presser foot area is generally carried out using the finite element method, but the accurate application of local loads and the reasonable evaluation of the results have always been a problem for engineers, and there is no public strength check of the hanging point area. method introduction

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