Helicopter shipboard towed load calculation method and device

Abstract

The application belongs to the field of helicopter comprehensive strength, and relates to a method and device for calculating a towing load of a helicopter on a ship. The method comprises the following steps: considering ship sway load, wind load, towing resistance and landing gear load to establish a balance equation of the helicopter according to the following principles, so as to obtain a tail landing gear load; and according to the tail landing gear load and the known towing force provided by a towing vehicle on the ground to tow the helicopter, a resultant force in the towing direction on the tail landing gear is obtained, that is, the towing load.

Description

Technical Field

[0001] This invention belongs to the field of helicopter comprehensive strength and relates to a method and device for calculating the traction load on a helicopter ship. Background Technology

[0002] For land-based traction, existing technical specifications stipulate traction load factors to cover traction loads under various complex conditions.

[0003] The traction situation on a ship's deck differs from that on land, and there are currently no empirical coefficients. No publicly available patents or papers describe relevant methods.

[0004] To perform strength design of shipborne helicopter structures and towing structures, it is necessary to comprehensively consider meteorological and sea conditions, helicopter parameters, and accurately determine the ship's towing load. Summary of the Invention

[0005] The purpose of this invention is to calculate the traction load of a ship-borne towing helicopter, filling a gap in the field.

[0006] The technical solution of this invention:

[0007] A method for calculating the towing load on a helicopter ship includes:

[0008] The balance equations for the helicopter are established by considering ship sway load, wind load, traction drag, and landing gear load according to the following principles, so as to obtain the tail landing gear load excluding DBP.

[0009] Based on the tail landing gear load and the known traction force required for the towing vehicle to tow the helicopter on the ground, the resultant force in the traction direction on the tail landing gear is calculated as the traction load.

[0010] The principles include:

[0011] (1) A helicopter has no other acceleration motion except for the acceleration due to drag.

[0012] (2) The acceleration drag of the helicopter acts on the center of gravity of the helicopter, and the rolling drag of the helicopter acts on the tire contact point; the acceleration drag and the rolling drag of the helicopter are in the opposite direction to the traction direction.

[0013] (3) Conservatively, it is assumed that the rolling resistance of the helicopter is evenly borne by the left and right main landing gears, and the tail landing gear does not bear the rolling resistance.

[0014] (4) Assume that the lateral friction forces on the left and right main landing gears are equal: Fy 左起 =Fy 右起 ;

[0015] (5) The load application points of the left and right starting points are at the tire contact point, and the load application point of the rear starting point is at the tire center.

[0016] (6) Divide the situation into the case where the traction direction is the same as the travel direction and the case where the traction direction is opposite to the travel direction.

[0017] Traction load F 牵引 The calculation formula is:

[0018]

[0019] in, This refers to the traction load on the tail landing gear that affects the helicopter's heading. α is the lateral traction load on the tail landing gear of the helicopter, α is the preset traction angle, and DBP is the traction force required for the towing vehicle to tow the helicopter on the ground.

[0020] Fx 尾起 The traction load on the tail landing gear excluding DBP in the helicopter's heading; Fy 尾起 The lateral traction load on the tail landing gear of the helicopter, excluding DBP.

[0021] The formula for calculating DBP is:

[0022] DBP=AR a +RR a ;

[0023] AR a =0.015mg;

[0024] RR a =0.022mg;

[0025] In the formula:

[0026] DBP—The traction force borne by the towing bolt of the tractor when in motion;

[0027] AR a —Aircraft acceleration drag;

[0028] RR a —The resistance of the aircraft rolling.

[0029] AR a RR a The sign of DBP is determined by the traction direction; it is positive when pulling and negative when pushing.

[0030] The equilibrium equations for a helicopter are:

[0031] Fx=0:Fx 风 +Fx 舰船 +Fx 尾起 -AR a ·cosα-RR a·cosα+DBP·cosα=0;

[0032] Fy = 0:Fy 风 +Fy 舰船 +Fy 左起 +Fy 右起 +Fy 尾起 -AR a ·sinα-RR a sinα + DBP sinα = 0;

[0033] Fz = 0:Fz 风 +Fz 舰船 +Fz 左起 +Fz 右起 +Fz 尾起 =0;

[0034]

[0035]

[0036]

[0037] In the formula:

[0038] Fx 风 Fy 风 Fz 风 Mx 风 My 风 Mz 风 Given the known components of force and moment of the wind load in each direction, with the load application point at the center of the wind load [x] 风 y 风 , z 风 ];

[0039] Fx 舰船 Fy 舰船 Fz 舰船 Given the ship's known inertial load, generated by the ship's yaw, with the load point at the center of gravity [x] 重心 y 重心 , z 重心 ];

[0040] Fx 左起 Fy 左起 Fz 左起 The load on the left landing gear does not include rolling resistance, and the point of application is the tire contact point [x] 左起 y 左起 , z 左起 ], where Fx 左起 =0,Fy 左起 This refers to the lateral friction force of the left landing gear.

[0041] Fx 右起 Fy 右起 Fz 右起 The load on the right landing gear does not include rolling resistance, and the point of application is the tire contact point [x] 右起 y 右起 , z 右起 ], where Fx 右起 =0,Fy 右起 This refers to the lateral friction force of the right landing gear.

[0042] Fx 尾起 Fy 尾起 Fz 尾起 The tail landing gear load does not include DBP, and the point of application is the tire center [x] 尾起 y 尾起 , z 尾起 ], Fx 尾起 and Fy 尾起 The resultant force of the component in the traction direction and DBP is the traction load, and the component perpendicular to the traction direction is the lateral friction force.

[0043] Fx, Fy, Fz, Mx, My, and Mz are the components of the resultant force and torque of the helicopter in each direction, all of which are 0.

[0044] A helicopter-borne towing load calculation device includes:

[0045] A module is established to establish the helicopter's equilibrium equations based on the following principles, considering ship sway load, wind load, traction drag, and landing gear load, to obtain the tail landing gear load excluding DBP.

[0046] The calculation module is used to calculate the resultant force in the traction direction on the tail landing gear, which is the traction load, based on the tail landing gear load and the known traction force required by the towing vehicle to tow the helicopter on the ground.

[0047] The principles include:

[0048] (1) A helicopter has no other acceleration motion except for the acceleration due to drag.

[0049] (2) The acceleration drag of the helicopter acts on the center of gravity of the helicopter, and the rolling drag of the helicopter acts on the tire contact point; the acceleration drag and the rolling drag of the helicopter are in the opposite direction to the traction direction.

[0050] (3) Conservatively, it is assumed that the rolling resistance of the helicopter is evenly borne by the left and right main landing gears, and the tail landing gear does not bear the rolling resistance.

[0051] (4) Assume that the lateral friction forces on the left and right main landing gears are equal: Fy 左起 =Fy 右起 ;

[0052] (5) The load application points of the left and right starting points are at the tire contact point, and the load application point of the rear starting point is at the tire center.

[0053] (6) Divide the situation into the case where the traction direction is the same as the travel direction and the case where the traction direction is opposite to the travel direction.

[0054] Traction load F 牵引 The calculation formula is:

[0055] in, This refers to the traction load on the tail landing gear that affects the helicopter's heading. α is the lateral traction load on the tail landing gear of the helicopter, α is the preset traction angle, and DBP is the traction force required for the towing vehicle to tow the helicopter on the ground.

[0056] Fx 尾起 The traction load on the tail landing gear excluding DBP in the helicopter's heading; Fy 尾起 The lateral traction load on the tail landing gear of the helicopter, excluding DBP.

[0057] The formula for calculating DBP is:

[0058] DBP=AR a +RR a ;

[0059] AR a =0.015mg

[0060] RR a =0.022mg

[0061] In the formula:

[0062] DBP—The traction force borne by the towing bolt of the tractor when in motion;

[0063] AR a —Aircraft acceleration drag;

[0064] RR a —The resistance of the aircraft rolling.

[0065] The beneficial effects of this invention are: This method can accurately calculate the traction load on a helicopter on a ship, and can provide input for the strength design of helicopters. Detailed Implementation

[0066] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0067] The conditions on the ship's deck differ from those on land, and there are currently no empirical coefficients. The load that can normally tow a helicopter under harsh working conditions will be taken as the ship's deck towing load. The towing vehicle should be able to overcome the following loads to tow a helicopter:

[0068] 1) Inertial load on the ship; 2) Wind load; 3) Without considering the motion on the ship and wind load, the tractor needs to provide traction to overcome the acceleration drag and rolling drag of the aircraft.

[0069] Considering the ship's rolling load, wind load, and landing gear load, a balance equation is established, and the resultant force in the traction direction on the tail landing gear is the traction load.

[0070] This method establishes the solution equations based on the following principles:

[0071] (1) The helicopter has no acceleration motion other than the acceleration due to the drag.

[0072] (2) The acceleration drag of the aircraft acts on the center of gravity of the helicopter, while the rolling drag of the aircraft acts on the tire contact point. The directions of the acceleration drag and the rolling drag of the aircraft are opposite to the traction direction.

[0073] (3) Conservatively, it is assumed that the rolling resistance of the aircraft is evenly borne by the left and right main landing gears, and the tail landing gear does not bear the rolling resistance.

[0074] (4) Assume that the lateral friction forces on the left and right main landing gears are equal: Fy 左起 =Fy 右起

[0075] (5) The load application points of the left and right starting points are at the tire contact point, while the load application point of the rear starting point is at the tire center.

[0076] (6) Divide the situation into the case where the traction direction is the same as the travel direction (pull) and the case where the traction direction is opposite to the travel direction (push).

[0077] The variables to be solved are the forces in three directions on the landing gear. Among them, the main landing gear's x-direction load is the rolling resistance component and does not need to be solved. Therefore, the unknown quantity to be solved is Fy. 左起 Fz 左起 Fy 右起 Fz 右起 Fx 尾起 Fy 尾起 Fz 尾起There are 7 in total, solved by 6 equilibrium equations and 1 supplementary equation Fy. 左起 =Fy 右起 There are a total of 7 equations to solve.

[0078] Load balance equations:

[0079] Fx=0:Fx 风 +Fx 舰船 +Fx 尾起 -AR a ·cosα-RR a ·cosα+DBP·cosα=0

[0080] Fy = 0:Fy 风 +Fy 舰船 +Fy 左起 +Fy 右起 +Fy 尾起 -AR a ·sinα-RR a ·sinα+DBP·sinα=0

[0081] Fz = 0:Fz 风 +Fz 舰船 +Fz 左起 +Fz 右起 +Fz 尾起 =0

[0082]

[0083]

[0084]

[0085] In the formula:

[0086] α is the traction angle.

[0087] Fx 风 Fy 风 Fz 风 Mx 风 My 风 Mz 风 The components of the force and moment of the wind load in each direction are given, with the load application point at the center of the wind load [x]. 风 y 风 , z 风 ];

[0088] Fx 舰船 Fy 舰船 Fz 舰船 This is the ship's inertial load, generated by the ship's yaw, with the load point at the center of gravity [x]. 重心 y 重心, z 重心 ];

[0089] Fx 左起 Fy 左起 Fz 左起 The load on the left landing gear does not include rolling resistance, and the point of application is the tire contact point [x] 左起 y 左起 , z 左起 ], where Fx 左起 =0,Fy 左起 This refers to the lateral friction force of the left landing gear.

[0090] Fx 右起 Fy 右起 Fz 右起 The load on the right landing gear does not include rolling resistance, and the point of application is the tire contact point [x] 右起 y 右起 , z 右起 ], where Fx 右起 =0,Fy 右起 This refers to the lateral friction force of the right landing gear.

[0091] Fx 尾起 Fy 尾起 Fz 尾起 The tail landing gear load does not include DBP, and the point of application is the tire center [x] 尾起 y 尾起 , z 尾起 ], Fx 尾起 and Fy 尾起 The resultant force of the component in the traction direction and DBP is the traction load, and the component perpendicular to the traction direction is the lateral friction force.

[0092] DBP refers to the traction force required for the towing vehicle to tow a helicopter on the ground; AR a RR a The sign of DBP is determined by the traction direction; it is positive when pulling and negative when pushing.

[0093] Therefore, the resultant force of the load on the landing gear is:

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] Ignoring ship motion and wind load, the formula for calculating the traction force required by the towing vehicle is as follows:

[0105] DBP=AR a +RR a +GR a

[0106] In the formula:

[0107] DBP—The traction force borne by the towing bolt of the tractor when in motion;

[0108] AR a —Aircraft acceleration drag;

[0109] RR a —The drag of the aircraft rolling;

[0110] GR a —Aircraft uphill drag.

[0111] The overload caused by the ship's rolling is calculated separately, and there is no uphill situation, therefore GR a =0.

[0112] The acceleration drag of an aircraft is calculated using the following formula:

[0113] AR a =α·m·g

[0114] α—Acceleration drag coefficient, taken as 0.015;

[0115] m — Aircraft mass;

[0116] g — acceleration due to gravity.

[0117] The rolling resistance of an aircraft is calculated using the following formula:

[0118] RR a =β·m·g

[0119] β—Rolling resistance coefficient, taken as 0.022 for wet concrete pavement.

[0120] Therefore,

[0121] Aircraft acceleration drag: AR a=α·m·g=0.015mg

[0122] Aircraft rolling resistance: RR a =β·m·g=0.022mg

[0123] Without considering ship motion and wind load, the tractor unit needs to provide the following tractive force:

[0124] DBP=AR a +RR a +GR a +ET=0.015mg+0.022mg+0+0=0.037mg

[0125] The key point of this invention is the solution equation established based on the assumptions.

[0126] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the traction load on a helicopter ship, characterized in that, include: The balance equations for the helicopter are established by considering the ship's rolling load, wind load, traction drag, and landing gear load according to the following principles, and the tail landing gear load is obtained. Based on the tail landing gear load and the known traction force required for the towing vehicle to tow the helicopter on the ground, the resultant force in the traction direction on the tail landing gear is calculated as the traction load. The principles include: (1) The helicopter has no acceleration motion other than the acceleration due to drag; (2) The acceleration drag of the helicopter acts on the center of gravity of the helicopter, and the rolling drag of the helicopter acts on the tire contact point; the acceleration drag and the rolling drag of the helicopter are in the opposite direction to the traction direction. (3) Conservatively, it is assumed that the rolling resistance of the helicopter is evenly borne by the left and right main landing gears, and the tail landing gear does not bear the rolling resistance. (4) Assume that the lateral friction forces on the left and right main landing gears are equal: ; (5) The load application points of the left and right wheels are at the tire contact point, and the load application point of the rear wheel is at the tire center; (6) Divide the cases where the traction direction is the same as the travel direction and the cases where the traction direction is opposite to the travel direction; Traction load F 牵引 The calculation formula is: ； ， ； in, This refers to the traction load on the tail landing gear that affects the helicopter's heading. α is the lateral traction load on the tail landing gear of the helicopter, α is the preset traction angle, and DBP is the traction force required for the towing vehicle to tow the helicopter on the ground. The traction load on the tail landing gear in the helicopter's heading, excluding DBP; The lateral traction load on the tail landing gear of the helicopter, excluding DBP; The formula for calculating DBP is:

2. The method according to claim 1, characterized in that, AR a , RR a The sign of DBP is determined by the traction direction; it is positive when pulling and negative when pushing.

3. The method according to claim 1, characterized in that, The equilibrium equations for a helicopter are: ； ； ； In the formula: Given the known components of force and moment of the wind load in each direction, with the load application point at the center of the wind load. ]; Given the known inertial loads of the ship, generated by the ship's yaw, with the load point at the center of gravity. ]; The load on the left landing gear does not include rolling resistance, and the point of application is the tire contact point. ],in , This refers to the lateral friction force of the left landing gear. The load on the right landing gear does not include rolling resistance, and the point of application is the tire contact point. ],in , This refers to the lateral friction force of the right landing gear. The tail landing gear load, excluding DBP, is applied at the tire center. ], and The resultant force of the component in the traction direction and DBP is the traction load, and the component perpendicular to the traction direction is the lateral friction force. The components of the resultant force and torque of the helicopter in each direction are all 0.

4. A helicopter-borne traction load calculation device, characterized in that, include: A module is established to establish the helicopter's equilibrium equations based on the following principles, considering ship sway load, wind load, traction drag, and landing gear load, to obtain the tail landing gear load excluding DBP. The calculation module is used to calculate the resultant force in the traction direction on the tail landing gear, which is the traction load, based on the tail landing gear load and the known traction force required by the towing vehicle to tow the helicopter on the ground. The principles include: (1) The helicopter has no acceleration motion other than the acceleration due to drag; (2) The acceleration drag of the helicopter acts on the center of gravity of the helicopter, and the rolling drag of the helicopter acts on the tire contact point; the acceleration drag and the rolling drag of the helicopter are in the opposite direction to the traction direction. (3) Conservatively, it is assumed that the rolling resistance of the helicopter is evenly borne by the left and right main landing gears, and the tail landing gear does not bear the rolling resistance. (4) Assume that the lateral friction forces on the left and right main landing gears are equal: ; (5) The load application points of the left and right wheels are at the tire contact point, and the load application point of the rear wheel is at the tire center; (6) Divide the cases where the traction direction is the same as the travel direction and the cases where the traction direction is opposite to the travel direction; Traction load F 牵引 The calculation formula is: ； ， ； in, This refers to the traction load on the tail landing gear that affects the helicopter's heading. α is the lateral traction load on the tail landing gear of the helicopter, α is the preset traction angle, and DBP is the traction force required for the towing vehicle to tow the helicopter on the ground. The traction load on the tail landing gear in the helicopter's heading, excluding DBP; The lateral traction load on the tail landing gear of the helicopter, excluding DBP; The formula for calculating DBP is:

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