CN-115408734-B - Cylindrical airbag tiling and folding model for computer simulation and optimization method

Abstract

The invention discloses a cylindrical air bag tiling folding model for computer simulation and an optimization method, wherein the air bag surface consists of two end circular surfaces and a middle cylindrical surface, the two end circular surfaces are flatly folded in the surfaces of the cylindrical surfaces, the air bag surface is folded into four layers of planes, the first layer is a first outer plane, the second layer comprises a first inner plane and a second inner plane, the third layer comprises a third inner plane and a fourth inner plane, and the fourth layer is a second outer plane. The invention can fully fold the round surfaces at two ends of the cylindrical air bag into the cylindrical surface of the air bag, greatly reduces the external dimension of the tiled folding model, has simple tiled folding modeling method, can adjust the external profiles of the tiled folding models with different sizes according to the actual engineering conditions by setting the distances between the short top edges of the trapezoid surfaces of the four inner planes and the symmetry transverse axis of the folding model, and can determine the final tiled folding model by optimizing and calculating the height value of the trapezoid surfaces.

Inventors

• ZHANG ANPING

Assignees

• 南京航空航天大学

Dates

Publication Date

20260505

Application Date

20220815

Claims (1)

1. 1. The cylindrical airbag tiling and folding model for computer simulation comprises an airbag surface consisting of two end circular surfaces and a middle cylindrical surface, wherein the two end circular surfaces are folded in a flat manner in the plane of the cylindrical surface, the airbag surface is folded into four layers of planes, the first layer is a first outer plane, the second layer comprises a first inner plane and a second inner plane, the third layer comprises a third inner plane and a fourth inner plane, and the fourth layer is a second outer plane; the first outer plane and the second outer plane are mirror images, the first inner plane and the second inner plane are symmetrically folded under the first outer plane, the third inner plane and the fourth inner plane are symmetrically folded over the second outer plane, the first inner plane and the third inner plane are mirror images, and the second inner plane and the fourth inner plane are mirror images; The first outer plane and the second outer plane are identical in shape and are composed of arc surfaces with two symmetrical ends and a rectangular surface in the middle, the arc surfaces and the rectangular surface in the middle respectively comprise two arc line sides and two straight line sides, and the distance between the two straight line sides is equal to half of the circumference length of the round surfaces at the two ends of the air bag; The first to fourth inner planes are identical in shape and are composed of trapezoid surfaces and arc surfaces, the top edge length of each trapezoid surface is equal to the diameter of the round surfaces at the two ends of the cylindrical air bag, and the bottom edge length is equal to half of the circumferential length of the round surfaces at the two ends of the air bag; the arc edge of the first outer plane is overlapped with the arc edges of the first inner plane and the second inner plane which are right below the first outer plane, and the arc edge of the second outer plane is overlapped with the arc edges of the third inner plane and the fourth inner plane which are right above the second outer plane; the straight line edges of the first inner plane and the third inner plane are overlapped; the optimization method for the cylindrical airbag tiling and folding model for computer simulation is characterized by comprising the following specific steps of: The method comprises the steps of setting the distance between the short top edge of the trapezoid surface of the inner plane and the symmetry transverse axis of the folding model, adjusting the outline of the tiled folding model, obtaining the height value of the trapezoid surface of the inner plane through optimization calculation, obtaining the minimum value of the difference value between the three-dimensional cylindrical surface area and the tiled folding area, and determining the optimal tiled folding model.

Description

Cylindrical airbag tiling and folding model for computer simulation and optimization method Technical Field The invention relates to the technical field of aerospace, in particular to a cylindrical airbag tiling and folding model for computer simulation and an optimization method. Background In the technical field of aerospace, the cylindrical airbag has the advantages of very simple structure and low cost, and is widely applied to ground contact buffering and shock absorption of aircraft recovery. The cylindrical air bag is folded and placed in the air bag cabin before the cylindrical air bag is inflated and unfolded in the air. In aircraft design, it is desirable that the size of the air bag module be as small as possible, and therefore the air bag needs to be folded as small as possible. At present, a computer simulation technology is mainly applied to simulate the folding and inflation and unfolding of an air bag so as to optimally design the air bag and an aircraft. The folding modeling of the air bag comprises a direct folding method, an initial matrix method, a nonlinear dynamics method and a reverse modeling method. In computer simulation, the direct folding method establishes a corresponding folding simulation model according to the actual folding condition of the air bag, and folds the cylindrical air bag by using an initial matrix method, a nonlinear dynamics method and a reverse modeling method, so that the process is complex. In the patent of application publication number CN110738004a, a folding model of a cylindrical fabric is established using a direct folding method, but in this model, the round surfaces at both ends of the cylindrical fabric are not completely folded into the cylindrical surface, and the model cannot make the overall outline size of the fabric after being tiled and folded smaller, so the folding model cannot meet the requirement of the size of the airbag compartment as small as possible in the aircraft design. Disclosure of Invention Aiming at the defects related to the background technology, the invention provides a cylindrical airbag tiling and folding model for computer simulation and an optimization method. The invention adopts the following technical scheme for solving the technical problems: The cylindrical airbag tiling folding model is used for computer simulation, the surface of an airbag consists of two end circular surfaces and a middle cylindrical surface, the two end circular surfaces are flatly folded in the surfaces of the cylindrical surfaces, the surface of the airbag is folded into four layers of planes, a first layer is a first outer plane, a second layer comprises a first inner plane and a second inner plane, a third layer comprises a third inner plane and a fourth inner plane, and a fourth layer is a second outer plane; the first outer plane and the second outer plane are mirror images, the first inner plane and the second inner plane are symmetrically folded under the first outer plane, the third inner plane and the fourth inner plane are symmetrically folded over the second outer plane, the first inner plane and the third inner plane are mirror images, and the second inner plane and the fourth inner plane are mirror images; The first outer plane and the second outer plane are identical in shape and are composed of arc surfaces with two symmetrical ends and a rectangular surface in the middle, the arc surfaces and the rectangular surface in the middle respectively comprise two arc line sides and two straight line sides, and the distance between the two straight line sides is equal to half of the circumference length of the round surfaces at the two ends of the air bag; The first to fourth inner planes are identical in shape and are composed of trapezoid surfaces and arc surfaces, the top edge length of each trapezoid surface is equal to the diameter of the round surfaces at the two ends of the cylindrical air bag, and the bottom edge length is equal to half of the circumferential length of the round surfaces at the two ends of the air bag; the arc edge of the first outer plane is overlapped with the arc edges of the first inner plane and the second inner plane which are right below the first outer plane, and the arc edge of the second outer plane is overlapped with the arc edges of the third inner plane and the fourth inner plane which are right above the second outer plane; the straight line edges of the first inner plane and the third inner plane are overlapped, and the straight line edges of the second inner plane and the fourth inner plane are overlapped. The invention also discloses an optimization method of the cylindrical air bag tiling and folding model for computer simulation, which comprises the steps of adjusting the outline of the tiling and folding model by setting the distance between the short top edge of the trapezoid surface of the inner plane and the symmetry transverse axis of the folding model, obtaining the height value of the tra