CN109703781B - Calculation design method of lever system - Google Patents
Calculation design method of lever system Download PDFInfo
- Publication number
- CN109703781B CN109703781B CN201811493848.7A CN201811493848A CN109703781B CN 109703781 B CN109703781 B CN 109703781B CN 201811493848 A CN201811493848 A CN 201811493848A CN 109703781 B CN109703781 B CN 109703781B
- Authority
- CN
- China
- Prior art keywords
- lever
- equipment
- load
- calculation
- loading
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a computing design method of a lever system. The method comprises the steps of simplifying a lever system design object by using a gravity influence coefficient and a standard local coordinate system, then calculating a lever connection form and lever equipment parameters layer by layer from the top down from the whole load by adopting a recursive calculation method, and then calculating connecting piece equipment parameters, designing levers and connecting piece equipment by layer from the bottom up from load nodes; and carrying out equipment weight influence processing and correcting lever system equipment parameter data in the regression calculation process. And finally, carrying out equipment interference inspection on the designed lever system by a lever system equipment interference inspection method. The method for calculating and designing the lever system is not only suitable for designing the lever system in the static strength of the airplane structure, but also suitable for designing the lever system in static strength tests of other various structures.
Description
Technical Field
The invention relates to a calculation design method of a lever system in the field of static strength tests of aircraft structures, wherein the lever system is an important equipment system for distributing and applying test loads in the static strength tests of the aircraft structures.
Background
In the static strength test of the airplane structure, various loads (inertial loads, pneumatic loads, concentrated loads and the like) borne by the test structure in the test condition are equivalent to a considerable amount of concentrated loads which are called load nodes and are arranged on the test structure, and the static strength test of the airplane structure simulates the actual loaded condition of the test structure by applying the test loads to the load nodes. In the test process, test loads need to be applied to a considerable number of load nodes, however, the number of actuators which can be used is limited by the test control system and the installation environment of the loading equipment, so that only a small number of actuators can be used for applying test loads to a large number of load nodes, and a lever system (as shown in fig. 1) is a device for completing the load applying function.
In the static strength test of the airplane structure, load nodes are divided according to the test condition and the structure part, so that the load nodes in the same subarea have the same loading direction and become parallel loading force systems, and the load nodes in the subareas can be loaded by a single actuator through a lever system. The lever system calculation design is the design for completing the calculation of various lever and connector equipment parameters and connection forms in the equipment system.
In a common connection design, two-by-two connection and calculation are carried out from a load node, a lever and a connecting piece device are designed, and the lever loading center is used as a new load node to carry out two-by-two connection and calculation again. And (5) designing the connection upwards level by level, and finally reaching the top lever to finish the connection design of the whole lever system. The design of connecting the load nodes upwards level by level lacks the overall consideration of load distribution, and the situation that the length difference of the force arms at two ends of the lever is large can occur in the connection process, so that the accuracy and the reliability of the load applied by the whole lever system are reduced.
The weight of the lever system equipment generates certain additional force and additional moment on the test load, thereby influencing the accuracy of the test. The usual approach is to eliminate the additional force and moment created by the weight of the device by adding a weight to the lever, aligning the center of gravity of the lever and link device with the center of lever loading and modifying the test load. And the weight of each device in the lever system is equivalent to the additional force on the load node, and the additional force and the additional moment generated by the weight of the device are eliminated by adding a counter weight or a counter weight part on the load node. No matter the counter weight or counter weight is added on the lever or the load node, the mounting difficulty of the lever system equipment is increased, and the reliability and the safety of the test loading device are reduced.
Interference checking between devices of a lever system has been lacking in a computer-implemented, unified, efficient method, making interference checking between devices in a lever system design more dependent on the experience of the designer. In addition, the common lever system design method and the equipment weight processing method are related to a specific test loading direction, and the universality is poor.
Disclosure of Invention
Object of the Invention
The invention provides a new calculation and design method of a lever system, which can calculate and design the lever system of a load node of a parallel force system in any loading direction, and provides a new equipment weight processing method and an equipment interference checking method.
Technical solution of the invention
In order to achieve the purpose, the invention adopts the following technical scheme:
firstly, the design object of the lever system is simplified by using the gravity influence coefficient and the standard local coordinate system, so that the lever system design in any loading direction and any coordinate system becomes a simple and standard lever system design irrelevant to the loading direction. Calculating the lever connection form and the lever equipment parameters layer by layer from the whole load from top to bottom by adopting a special recursive calculation method, and then calculating the connecting piece equipment parameters, designing the lever and the connecting piece equipment from the load node from bottom to top by layer; and in the regression calculation process, equipment weight processing and equipment interference check are carried out, and lever system equipment parameter data are corrected. The additional moment generated by the weight of the equipment is eliminated by correcting the loading center position of the lever and changing the length of force arms at two ends of the lever, and the additional force generated by the weight of the equipment is eliminated by correcting the test load value; an equipment containing rectangle is established by projecting the lever system equipment on a specific plane in a standard local coordinate system, and then the interference condition between the equipments is checked by using the intersection between the equipment containing rectangles.
A calculation design method of a lever system is characterized in that a gravity influence coefficient and a standard local coordinate system are used for simplifying a lever system design object; the computing design of the lever system is carried out by using a special recursive algorithm, namely: designing a lever system connection form in the progressive process, calculating equipment parameters in the regression process and correcting the parameters; the inventive calculation and processing method is used for carrying out equipment weight processing and equipment interference check of the lever system.
Preferably, the rules and methods in the calculation and design process of the lever system are as follows:
(1) gravity influence coefficient: and taking the negative value of the unit gravity vector projected in the loading direction as a calculation coefficient. Multiplying the weight of various lever system equipment obtained by calculation or obtained by database retrieval by the coefficient in the design process to be used as an additional load generated by the weight of the test equipment, so that the subsequent moment, load correction calculation and design process are independent of the loading direction and a coordinate system;
(2) standard local coordinate system: and carrying out coordinate system rotation transformation on load node data of the lever system in design to enable one coordinate axis of the new coordinate system to be parallel to the loading direction, and calling the coordinate axis as a standard local coordinate system. In a standard local coordinate system, the spatial positions of a load pressure center, a lever end point and the like are changed into planes, the length and position calculation of the connecting piece is changed into height calculation, and the interference inspection process of lever system equipment can be simplified;
(3) the recursive connection calculation method comprises the following steps: the lever system recursive connection calculation design method is characterized in that:
process 1: in the progressive calculation process, one load node set is divided into two subsets which are respectively used as load nodes connected with the left end and the right end of the current lever, and the load node subsets are divided according to the rule that the difference of the total load values of the left end and the right end of the lever is minimum. Various equipment parameters of the current lever are calculated using the load node data in each subset. And respectively carrying out the same rule division and processing calculation on the subset until only one load node exists in the set.
And (2) a process: and in the regression calculation process, starting from the load node with the highest height, using the shortest connecting piece equipment meeting the bearing requirement, taking the length of the connecting piece as an initial value, and taking the lever holding level as a limiting condition to finish the parameter calculation of the connecting piece equipment at two ends of the lever. And (4) processing and calculating the influence of the weight of the current lever and the connecting piece equipment at the left end and the right end of the current lever, and correcting the length of the lever arm, the loading center position and the test load data. And then taking the current lever loading center and the test load as load node data, and using the same rule and method to calculate the parameters of the superior lever and the connecting piece device until the superior lever is reached.
(4) The weight processing method of the equipment, the weight of the lever system equipment generates additional force and additional moment, so that the test load is not only unequal in quantity but also inconsistent in distribution with the actual requirement. The method for processing the weight influence of the test equipment is characterized by comprising the following steps: the device does not use a counterweight or counter-counterweight device, and the additional moment generated by the weight of the device is eliminated by modifying the loading center position of the lever, changing the length of the force arm at the two ends of the lever and then correcting the load numerical value.
(5) The equipment interference inspection method is characterized in that mutual interference between a lever and connector equipment in a lever system possibly occurs due to the volume, the space position and the like of the equipment, so that the installation of the lever system or the application of test load fails, and therefore, the design result of the lever system needs to be inspected. The technical characteristics of the interference inspection method of the test equipment are as follows: projecting the equipment in the lever system to a plane which takes the loading direction as the normal direction in a standard local coordinate system, and establishing a containing rectangle for the equipment projection. Whether the devices are interfered with each other is judged by checking intersection between the device containing rectangles with the same height or overlapped height ranges.
Preferably, the gravity influence coefficient w is calculated by the formula:
wherein:
in order to test the load vector,
is the gravity vector of the equipment, beta is the included angle between the test load vector and the gravity vector of the equipment, and the numerical range of w is [ -1, 1]。
Preferably, the calculation step for eliminating the weight influence of the equipment through the moment arm correction is as follows:
1) and (3) correcting and calculating the total length of the lever arm:
(Xlc,Ylc)，(Xrc,Yrc) The coordinates of the loading center or the loading node of the lower lever connected with the two ends of the lever are respectively; (X)lc,Ylc)，(Xrc,Yrc) Through the correction calculation of the force arm balance, the coordinate position is different from the left and right load pressure centers of the lever;
2) and (3) correcting and calculating the design load of the lever:
F＝Fl+Fr+w·(Pl+Pr+PB)
Fl、Frcorrected design load, P, of the lower lever connected to both ends of the lever, respectivelyl、Pr、PBThe weights of the connecting pieces at the two ends of the lever and the lever equipment are respectively, and w is a gravity influence coefficient;
3) and (3) correcting and calculating the balance of the lever arm:
the lever distributes the test load F of the loading center to the connecting pieces at the two ends of the lever through the left and right force arms, and the lever can accurately distribute the test load at the two ends of the lever only under the condition that the left and right force arms are balanced, namely the resultant moment on the lever relative to the loading center is 0.0; the lever arm balance correction calculation means that the resultant moment on the lever relative to the loading center is 0.0 by correcting the arm lengths at the two ends of the lever;
the distance from the gravity center of the lever equipment to the loading center of the lever is called the eccentricity E of the leverBAnd then, the lever moment arm balance correction calculation is carried out in two conditions:
3.1) center of gravity of lever equipment is coincident with loading center EBWhen the weight is 0.0, only the influence of the weights of the left connecting piece and the right connecting piece is considered; because the action points of the weights of the left and right two-end connecting pieces are the same as the action points of the left and right two-end test loads, the lengths of the left and right force arms after correction meet the following moment balance conditions:
from the above conditions it can be obtained:
3.2) misalignment of center of gravity and center of loading of the lever apparatus EB>0.0, the weight influence of the lever is considered while the weights of the left connecting piece and the right connecting piece are considered; by pair EBLeft and right force arms L in case of 0.0l、LrCorrecting the length delta L, and generating a new moment to offset the moment generated by the eccentricity of the lever;
and finally obtaining:
4) and (3) correcting and calculating a lever loading center:
calculating the position of the lever loading center by using the corrected lengths of the left and right force arms through the position of the lower lever loading center or the load node;
if: eB＝0.0
If: eB>0.0
Preferably, the lever system equipment interference check is divided into two steps: 1) checking the range of the installation height of the equipment, wherein if the installation heights of the lever and other levers are the same or the installation height of the lever is within the range of the height of the connecting piece equipment, the equipment can interfere with each other, and the range of the installation height is a necessary condition for equipment interference; 2) checking the device projection containing rectangle, when two devices meet the condition 1), further checking, and if the side line of the containing rectangle of a certain device is intersected with the side line of the containing rectangle of other devices, determining that the device is interfered with other devices.
Preferably, the lever system equipment interference checking method can be used in the regression process of the design calculation, and can also be used after the whole design is finished.
THE ADVANTAGES OF THE PRESENT INVENTION
The invention has the advantages that:
(1) the lever selection mode from top to bottom from the whole load always keeps the minimum difference of the load at each level and two ends of each lever in the lever system, and the designed lever system is optimal. The selection mode of the connecting piece from bottom to top from the load node can calculate and select the connecting piece according to the height of the load node or the lever loading center, and can effectively control the total height of the lever system, so that the lever system is easier to install and use. The gravity center of the lever and the equipment of the connecting piece is superposed with the loading center of the lever by correcting the length of the force arm at the two ends of the lever, thereby replacing a balance weight or a counter balance weight used by a lever system, reducing the complexity of the lever system and improving the reliability of the lever system.
(2) The standard local coordinates introduced in the lever system and the calculation design process not only simplify the calculation and judgment process of various parameters in the lever system design process, but also realize the equipment interference checking function in the lever system through the intersection calculation of the plane rectangular areas.
(3) The method for calculating and designing the lever system is not only suitable for designing the lever system in the static strength of the airplane structure, but also suitable for designing the lever system in static strength tests of other various structures.
Drawings
Fig. 1 is a diagram of a lever system connection form.
Fig. 2 is a schematic view of a containment rectangle of the lever device.
Detailed Description
The detailed description of the embodiments of the present invention is provided in conjunction with the summary of the invention and the accompanying drawings.
A calculation design method of a lever system comprises the following specific calculation processes:
step 1, calculating a gravity influence coefficient: the additional force generated by the weight of the lever and the connecting piece is always in the downward gravity direction, the loading direction of the lever system is in any direction, and the influence of the weight of the lever system on the test load is related to the loading direction, so that the calculation and design processes of the lever system are complicated. Introducing a gravity influence coefficient may simplify load calculations in the lever design.
The gravity influence coefficient is defined as the negative value of the unit gravity vector projected in the loading direction, namely:
wherein:
in order to test the load vector,
is the gravity vector of the equipment, beta is the included angle between the test load vector and the gravity vector of the equipment, and the numerical range of w is [ -1, 1]。
The weight of the lever and the connecting piece is multiplied by the gravity influence coefficient to be used as the additional force of the weight of the equipment to be directly superposed in the corresponding design load for moment balance calculation and load correction calculation, the factors of the loading direction and the coordinate system are not considered any more, and the calculation process is simplified.
Step 2, a standard local coordinate system: the load nodes are distributed in space along the surface of the structural test piece, the loading direction is any direction, the calculation processes of various parameters such as the lever loading center, the force arm end point, the position and the length of the connecting piece are complex due to the factors, and the equipment interference inspection difficulty during the design of a lever system is also caused. And (3) carrying out coordinate system rotation transformation on the load nodes in the partitions, wherein the rule of the rotation transformation is as follows: one coordinate axis of the new coordinate system is made parallel to the loading direction, and the new coordinate system is called a standard local coordinate system. In the new coordinate system, the spatial position calculation of the load pressure center and the lever end point is changed into plane position calculation, and the length and position calculation of the connecting piece is changed into height calculation. The interference check of the lever system equipment can be simplified from a space problem to a plane problem in a new coordinate system.
Suppose that: rotational transformationVector of the load
Become into
Then: the load pressure center, the lever end point position and the like are calculated by using (X, Y) coordinates, and the judgment of the position relation between the levers in each level and the interference inspection of the lever system equipment can be carried out in the (X, Y) plane; and the length and the position of the connecting piece only need to be calculated by using a Z coordinate. The coordinate system rotation transformation does not change the mutual position relation and the load numerical value among the load nodes, and does not influence the design result of the lever system.
Step 3, calculating recursive connections: the recursive algorithm is an algorithm for directly or indirectly calling the recursive algorithm, and the recursive algorithm can enable the structure of the developed computing design software of the lever system to be clear, easy to implement and easy to maintain. In the invention, the calculation of the lever and the connecting piece is respectively carried out in the progressive and regression processes, namely: calculating connection forms and lever parameters from a top lever downwards and level by level in the progressive process, and finally reaching a load node; in the regression process, the connection form and the connection parameters are calculated from the load node upwards and level by level, and finally the top lever is reached. And simultaneously carrying out equipment weight influence processing in the regression process, and correcting the data of the lever load, the moment arm and the loading center position.
In the progressive calculation process, a load node set is divided into two subsets which are respectively used as load nodes connected with the left end and the right end of the current lever, and the division rule is that the difference of total load values of the left end and the right end of the lever is minimum. And calculating various parameters of the current leverage equipment by using the load node data in each subset. And respectively carrying out division and processing calculation of the same rule on the two subsets, and processing the subset containing the load node at the higher position until only one load node in the set exists.
Assume that there are load nodes (Xi, Yi, Zi, Fi), i ═ 1,2, …, M, in a standard local coordinate system. Xi, Yi are position coordinates of the node i, Zi is height of the node i, and Fi is a load value of the node i.
Grouping the load nodes to enable the left and right ends of the lever to be loaded
The difference in the total load value of (a): n is selected so that |1.0-Fl/FrAnd | is minimal.
The device parameters and calculation formula of the lever are as follows:
load pressure centers at the left end and the right end of the lever:
total length of lever arm:
the length of the force arm at the left end and the right end of the lever is as follows:
lever loading center position:
in the regression calculation process, starting from the load node with the highest height, the shortest connecting piece equipment meeting the bearing requirements is used, the length of the connecting piece is used as an initial value, the lever holding level is used as a limiting condition, and the parameter calculation and design of the connecting piece equipment at two ends of the lever are completed. And (4) processing and calculating the weight influence of the current lever and the left and right connecting piece devices thereof, and correcting the length of the force arm at two ends of the lever, the loading center position and the test load data. And then, taking the current lever loading center and the test load as load node data, and using the same rule and method to calculate the parameters of the superior lever and the connector equipment until the superior lever is reached.
And 4, equipment weight influence treatment: the weight of the lever system equipment generates additional force and additional moment, so that the test load is not only unequal in quantity but also inconsistent in distribution with the actual requirement, and the test accuracy is damaged. The usual solution is to use a weight or counter-weight device and modify the test load values to eliminate these additional forces and moments. However, this will increase the difficulty of installation of the lever system equipment, reducing the reliability and safety of the test loading device.
Through correcting the length of the force arm at two ends of the lever, the center of gravity of the test equipment can be coincided with the lever loading center by changing the position of the loading center, and no counter weight or counter weight equipment is used, so that the mounting difficulty and the total weight of the lever system are reduced, and the safety and the reliability of the lever system are improved.
The weight of the lever system equipment is equivalent to additional force in the loading direction through a gravity influence coefficient, and the influence of the additional force on the test can be eliminated by correcting the length of the left and right force arms of each lever and the load value. The calculation steps for eliminating the weight influence of the equipment through the moment arm correction are as follows:
1) and (3) correcting and calculating the total length of the lever arm:
(Xlc,Ylc)，(Xrc,Yrc) Respectively, the loading center of the lower lever connected to both ends of the lever, or the coordinates of the load node. (X)lc,Ylc)，(Xrc,Yrc) Through the correction calculation of the force arm balance, the coordinate position is different from the left and right load pressure centers of the lever.
2) And (3) correcting and calculating the design load of the lever:
F＝Fl+Fr+w·(Pl+Pr+PB)
Fl、Frcorrected design load, P, of the lower lever connected to both ends of the lever, respectivelyl、Pr、PBThe weight of the connecting piece at the two ends of the lever and the lever equipment respectively, and w is the gravity influence coefficient.
3) And (3) correcting and calculating the balance of the lever arm:
the lever distributes the test load F of the loading center to the connecting pieces at the two ends of the lever through the left and right force arms, and the lever can accurately distribute the test load at the two ends of the lever only under the condition that the left and right force arms are balanced and the resultant moment on the lever relative to the loading center is 0.0. The lever arm balance correction calculation means that the resultant moment on the lever relative to the loading center is 0.0 by correcting the arm lengths at the two ends of the lever.
The distance from the gravity center of the lever equipment to the loading center of the lever is called the eccentricity E of the leverBAnd then, the lever moment arm balance correction calculation is carried out in two conditions:
3.1) center of gravity of lever equipment is coincident with loading center EBWhen 0.0, only the influence of the weight of the left and right links is considered. Because the action points of the weights of the left and right two-end connecting pieces are the same as the action points of the left and right two-end test loads, the lengths of the left and right force arms after correction meet the following moment balance conditions:
from the above conditions it can be obtained:
3.2) misalignment of center of gravity and center of loading of the lever apparatus EB>0.0, the weight of the left and right connecting pieces is considered, and the weight influence of the lever is also considered. By pair EBLeft and right force arms L in case of 0.0l、LrThe length is corrected by Delta L, and a new moment is generated to offset the moment generated by the eccentricity of the lever.
And finally obtaining:
4) and (3) correcting and calculating a lever loading center:
and calculating the position of the lever loading center by using the corrected lengths of the left and right force arms through the position of the lower lever loading center or the load node.
If: eB＝0.0
If: eB>0.0
Step 5, testing equipment interference inspection: the mutual interference between the lever and the connector in the lever system may be generated due to the factors such as the volume and the space position of the equipment, so that the installation of the lever system or the application of test load fails, and therefore, the design result needs to be checked in the design process or after the design of the lever system.
The interference situation of the lever system equipment is divided into two types: interference between lever devices, interference of levers with connector devices. In a standard local coordinate system, the interference between lever system equipment can be checked and judged through a projection area of the equipment on an XY plane.
A containing rectangle (as shown in fig. 2) is established for the projection of the lever and connector device in a plane (XY plane) taking the loading direction as a normal, and the containing rectangle is defined as: the minimum rectangle containing the projection area of the equipment in the XY plane is added with safety distance extension, namely: and the side lines of the rectangular area respectively move outwards for a safe distance to generate new rectangles. The safety distance is half of the minimum distance between the devices specified in practical use of the lever system.
The dimensions of the envelope rectangle projected by the lever and link device are very easily determined by the dimensions of the device, and the lever system device projection determines the position of all devices in a particular plane.
The interference check of the lever system equipment comprises two steps: 1) and (4) checking the installation height range of the equipment, wherein if the installation height of the lever is the same as that of other levers or the installation height of the lever is within the height range of the connector equipment, the equipment can interfere with each other, and the installation height range is a necessary condition for equipment interference. 2) Checking the device projection containing rectangle, when two devices meet the condition 1), further checking, and if the side line of the containing rectangle of a certain device is intersected with the side line of the containing rectangle of other devices, determining that the device is interfered with other devices.
The lever system equipment interference checking method can be used in the regression process of design calculation and can also be used after the whole design is finished.
Claims (6)
1. A calculation design method of a lever system is characterized by comprising the following steps: simplifying a lever system design object by using a gravity influence coefficient and a standard local coordinate system; then, the computing design of the lever system is carried out by using a special recursive algorithm: designing a lever system connection form in the progressive process, calculating equipment parameters in the regression process and correcting the parameters; then, processing the equipment weight of the lever system and checking the equipment interference;
gravity influence coefficient: taking a negative value projected by the unit gravity vector in the loading direction as a calculation coefficient; multiplying the weight of various lever system equipment obtained by calculation or obtained by database retrieval by the coefficient in the design process to be used as an additional load generated by the weight of the test equipment, so that the subsequent moment, load correction calculation and design process are independent of the loading direction and a coordinate system;
standard local coordinate system: carrying out coordinate system rotation transformation on load node data of the lever system in design to enable one coordinate axis of a new coordinate system to be parallel to the loading direction and to be called as a standard local coordinate system; in a standard local coordinate system, the space positions of the load pressure center and the lever end point become planes, the length and position calculation of the connecting piece becomes height calculation, and the interference inspection process of the lever system equipment can be simplified;
the recursive connection calculation method comprises the following steps: the lever system recursive connection calculation design method is characterized in that:
process 1: in the progressive calculation process, a load node set is divided into two subsets which are respectively used as load nodes connected with the left end and the right end of the current lever, and the load node subsets are divided according to the rule that the difference of the total load values of the left end and the right end of the lever is minimum; calculating various equipment parameters of the current lever by using the load node data in each subset; respectively carrying out division and processing calculation of the same rule on the subset until only one load node exists in the set;
and (2) a process: in the regression calculation process, starting from the load node with the highest height, the shortest connecting piece equipment meeting the bearing requirements is used, the length of the connecting piece is taken as an initial value, the lever holding level is taken as a limiting condition, and the parameter calculation of the connecting piece equipment at the two ends of the lever is completed; processing and calculating the influence of the weight of the current lever and the connecting piece equipment at the left end and the right end of the current lever, and correcting the length of the lever arm, the loading center position and test load data; and then taking the current lever loading center and the test load as load node data, and using the same rule and method to calculate the parameters of the superior lever and the connecting piece device until the superior lever is reached.
2. The method for computing and designing a lever system according to claim 1, wherein the rules and methods in the computing and designing process of the lever system are as follows:
the weight of the lever system equipment generates additional force and additional moment, so that the test load is not only unequal in quantity but also inconsistent in distribution with the actual requirement; the weight influence processing method of the test equipment comprises the following steps: the device does not use a counterweight or counter-counterweight device, but changes the length of force arms at two ends of a lever by modifying the loading center position of the lever to eliminate additional moment generated by the weight of the device, and then eliminates additional force generated by the weight of the device by correcting a load numerical value;
the equipment interference checking method comprises the following steps: projecting equipment in a lever system to a plane taking a loading direction as a normal direction in a standard local coordinate system, and establishing a containing rectangle for the equipment projection; whether the devices are interfered with each other is judged by checking intersection between the device containing rectangles with the same height or overlapped height ranges.
3. The method for computationally designing a lever system as claimed in claim 2, wherein the gravity influence coefficient w is calculated by the formula:
wherein:
in order to test the load vector,
is the gravity vector of the equipment, beta is the included angle between the test load vector and the gravity vector of the equipment, and the numerical range of w is [ -1, 1]。
4. The method for designing and calculating a lever system according to claim 2, wherein the step of calculating the weight of the equipment by correcting the moment arm comprises the following steps:
1) and (3) correcting and calculating the total length of the lever arm:
(Xlc,Ylc)，(Xrc,Yrc) The coordinates of the loading center or the loading node of the lower lever connected with the two ends of the lever are respectively; (X)lc,Ylc)，(Xrc,Yrc) Through the correction calculation of the force arm balance, the coordinate position is different from the left and right load pressure centers of the lever;
2) and (3) correcting and calculating the design load of the lever:
F＝Fl+Fr+w·(Pl+Pr+PB)
Fl、Frcorrected design load, P, of the lower lever connected to both ends of the lever, respectivelyl、Pr、PBThe weights of the connecting pieces at the two ends of the lever and the lever equipment are respectively, and w is a gravity influence coefficient;
3) and (3) correcting and calculating the balance of the lever arm:
the lever distributes the test load F of the loading center to the connecting pieces at the two ends of the lever through the left and right force arms, and the lever can accurately distribute the test load at the two ends of the lever only under the condition that the left and right force arms are balanced, namely the resultant moment on the lever relative to the loading center is 0.0; the lever arm balance correction calculation means that the resultant moment on the lever relative to the loading center is 0.0 by correcting the arm lengths at the two ends of the lever;
the distance from the gravity center of the lever equipment to the loading center of the lever is called the eccentricity E of the leverBAnd then, the lever moment arm balance correction calculation is carried out in two conditions:
3.1) center of gravity of lever equipment is coincident with loading center EBWhen the weight is 0.0, only the influence of the weights of the left connecting piece and the right connecting piece is considered; because the action points of the weights of the left and right two-end connecting pieces are the same as the action points of the left and right two-end test loads, the lengths of the left and right force arms after correction meet the following moment balance conditions:
from the above conditions it can be obtained:
3.2) misalignment of center of gravity and center of loading of the lever apparatus EB>0.0, the weight influence of the lever is considered while the weights of the left connecting piece and the right connecting piece are considered; by pair EBLeft and right force arms L in case of 0.0l、LrCorrecting the length delta L, and generating a new moment to offset the moment generated by the eccentricity of the lever;
and finally obtaining:
4) and (3) correcting and calculating a lever loading center:
calculating the position of the lever loading center by using the corrected lengths of the left and right force arms through the position of the lower lever loading center or the load node;
if: eB＝0.0
If: eB>0.0
5. The method for computationally designing a lever system as claimed in claim 2, wherein the interference check of the lever system equipment is performed in two steps: 1) checking the range of the installation height of the equipment, wherein if the installation heights of the lever and other levers are the same or the installation height of the lever is within the range of the height of the connecting piece equipment, the equipment can interfere with each other, and the range of the installation height is a necessary condition for equipment interference; 2) checking the device projection containing rectangle, when two devices meet the condition 1), further checking, and if the side line of the containing rectangle of a certain device is intersected with the side line of the containing rectangle of other devices, determining that the device is interfered with other devices.
6. The method as claimed in claim 2, wherein the lever system equipment interference check method can be used in the regression process of the design calculation or after the whole design is finished.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811493848.7A CN109703781B (en) | 2018-12-07 | 2018-12-07 | Calculation design method of lever system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811493848.7A CN109703781B (en) | 2018-12-07 | 2018-12-07 | Calculation design method of lever system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109703781A CN109703781A (en) | 2019-05-03 |
| CN109703781B true CN109703781B (en) | 2022-04-19 |
Family
ID=66255500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811493848.7A Active CN109703781B (en) | 2018-12-07 | 2018-12-07 | Calculation design method of lever system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109703781B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110108544A (en) * | 2019-05-09 | 2019-08-09 | 中国飞机强度研究所 | Radial lever load system space initial position determines method |
| CN110119569A (en) * | 2019-05-09 | 2019-08-13 | 中国飞机强度研究所 | A kind of test load lever system spatial movement analogy method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103196688A (en) * | 2013-03-25 | 2013-07-10 | 北京起重工具厂 | Lever type dynamic load test platform with loads adjustable |
| CN103630442A (en) * | 2013-12-04 | 2014-03-12 | 中国飞机强度研究所 | Aircraft structural strength test loading level |
| CN103678737A (en) * | 2012-09-07 | 2014-03-26 | 中国飞机强度研究所 | Lever system virtual assembly method |
| CN104029826A (en) * | 2014-06-24 | 2014-09-10 | 中国飞机强度研究所 | Taring computing method for airplane structural strength test |
| CN104075899A (en) * | 2013-03-25 | 2014-10-01 | 北京起重工具厂 | lever used in leveraged adjustable load dynamic test bench |
| CN104180999A (en) * | 2013-05-28 | 2014-12-03 | 哈尔滨建成集团有限公司 | Structural member static strength test load transmission device |
| CN107655650A (en) * | 2017-09-27 | 2018-02-02 | 上海交通大学 | Lever load system collision checking method for structural test |
| CN108090256A (en) * | 2017-11-30 | 2018-05-29 | 江西洪都航空工业集团有限责任公司 | A kind of lever diagram Automatic Drawing method based on CAD |
-
2018
- 2018-12-07 CN CN201811493848.7A patent/CN109703781B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678737A (en) * | 2012-09-07 | 2014-03-26 | 中国飞机强度研究所 | Lever system virtual assembly method |
| CN103196688A (en) * | 2013-03-25 | 2013-07-10 | 北京起重工具厂 | Lever type dynamic load test platform with loads adjustable |
| CN104075899A (en) * | 2013-03-25 | 2014-10-01 | 北京起重工具厂 | lever used in leveraged adjustable load dynamic test bench |
| CN104180999A (en) * | 2013-05-28 | 2014-12-03 | 哈尔滨建成集团有限公司 | Structural member static strength test load transmission device |
| CN103630442A (en) * | 2013-12-04 | 2014-03-12 | 中国飞机强度研究所 | Aircraft structural strength test loading level |
| CN104029826A (en) * | 2014-06-24 | 2014-09-10 | 中国飞机强度研究所 | Taring computing method for airplane structural strength test |
| CN107655650A (en) * | 2017-09-27 | 2018-02-02 | 上海交通大学 | Lever load system collision checking method for structural test |
| CN108090256A (en) * | 2017-11-30 | 2018-05-29 | 江西洪都航空工业集团有限责任公司 | A kind of lever diagram Automatic Drawing method based on CAD |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109703781A (en) | 2019-05-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109703781B (en) | Calculation design method of lever system | |
| US20190177010A1 (en) | Flight vehicle attitude control system design method and device | |
| CN107655650B (en) | Lever load system collision checking method for structural test | |
| CN107506552A (en) | Analysis method for reliability and system based on sensitivity test | |
| CN110348141A (en) | A kind of method of aero-engine external pipeline system fast vibration analysis | |
| CN112033331B (en) | Group hole measurement swing angle planning method based on three-coordinate measuring needle | |
| CN115357976A (en) | Iterative calculation method of large-span steel structure construction scheme based on structural performance | |
| CN103324032B (en) | Polyhedron main substrate, manufacturing method and processing method thereof | |
| CN115374667A (en) | Inverse analysis method based on influence of steel structure construction deformation on structure design performance | |
| CN110901898A (en) | Aircraft gravity center limiting method and device | |
| CN115935559A (en) | Downhole tool bending simulation method and device | |
| CN112231861B (en) | Cluster control moment gyroscope vibration isolation method for inhibiting attitude-adjusting resonance | |
| CN108803307A (en) | It is a kind of to be actively directed toward ultra quiet platform automatic fault diagnosis and fault tolerant control method and system | |
| CN111488684A (en) | Load balance calculation method | |
| CN108573110A (en) | CMP simulation method and system of multilayer interconnection line structure | |
| CN110879872B (en) | Vehicle system transfer function solving method based on transfer matrix | |
| CN108803233B (en) | Preparation method of mask | |
| CN108009082B (en) | Flight management-based combined test case generation method | |
| CN110108544A (en) | Radial lever load system space initial position determines method | |
| CN113673022A (en) | Method for calculating relative displacement between two points of deformation structure | |
| CN112861069B (en) | Method for calculating safety coefficient of homogeneous pure clay slope under action of external load | |
| CN113239468A (en) | Simulation analysis method for deformation of general lifting appliance | |
| CN107766679B (en) | Bus chassis module redesign method based on interface digital expression | |
| CN106842827B (en) | A method of reduce leads to silicon chip deformation by the absorption of photoetching work stage | |
| CN114112264B (en) | Helicopter control lever system support vibration fatigue test verification method and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |