CN112597558A - Method for loading torsion member and calculating pre-internal force - Google Patents
Method for loading torsion member and calculating pre-internal force Download PDFInfo
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Abstract
The invention relates to the technical field of structural engineering, and particularly discloses a method for calculating the loading and pre-internal force of a twisted member. And then respectively calculating the internal forces of the two supports based on the two supports in two different states and superposing the internal forces to obtain the target internal forces of the two supports. In this manner, the load is applied in stages so that the internal force of the torsion member is equalized. And because the preload is applied and removed in stages to provide the pre-internal force for the torsion member, the amplitude and the unevenness of the internal force of the torsion member are further reduced, the stress performance of the torsion member is improved, and the economy of the torsion member in the structure is improved.
Description
Technical Field
The invention relates to the technical field of structural engineering, in particular to a method for loading a torsion member and calculating a pre-internal force.
Background
In engineering theory, the stress of the torsion member is usually analyzed by adopting a mode that supports at two ends of the torsion member are fixedly supported at one time to bear full load. However, in actual design and construction (manufacturing), it is found that the torque generated by the torsion member calculated in the above manner under the load is often unevenly distributed, which easily results in poor deformation performance of the torsion member under the stress during actual design and construction (manufacturing), and reduces the economical efficiency of the torsion member in use in the structure.
Disclosure of Invention
The invention discloses a method for calculating the loading and the pre-internal force of a twisted member, which plays a role in doubly homogenizing the internal force of the twisted member by the connected state division, the load division application and the preload division application and removal, and improves the rationality and the economy of the twisted member in the structure.
In order to achieve the above object, an embodiment of the present invention provides a method for loading a torsion member and calculating a pre-internal force, where the method includes:
calculating all loads borne by the torsion member when the support of the torsion member is in an original connection state;
determining the internal force of a first support and a second support of the torsion member in the original connection state according to the total load, wherein the internal force of the first support is greater than that of the second support under the action of the total load;
adjusting the connection state of the first support from the original connection state to a first connection state, keeping the original connection state of the second support unchanged or increasing constraint rigidity to strengthen, and applying a first load and preload on the torsion member;
adjusting the connection state of the first mount from the first connection state to a second connection state, removing the preload and applying a second load on the torsion member;
respectively calculating internal forces of the first support and the second support in the first connection state based on the applied first load and the applied preload, respectively calculating internal forces of the first support and the second support in the second connection state based on the unloaded preload and the applied second load, superposing the internal forces of the first support in the first connection state and the second connection state to obtain a first support target internal force, and superposing the internal forces of the second support in the first connection state and the second connection state to obtain a second support target internal force;
wherein the sum of the first load and the second load is equal to the total load.
As an alternative implementation manner, in the embodiment of the present invention, the connection rigidity of the first support in the original connection state and the second connection state is greater than the connection rigidity of the first support in the first connection state.
As an optional implementation manner, in an embodiment of the present invention, the original connection state is a hinged state, a semi-rigid connection, or a rigid connection, the first connection state is a cantilever state, a hinged state, a semi-rigid connection, or a rigid connection, and the constraint number of the second connection state is not less than the constraint number of the original connection state.
As an optional implementation manner, in the embodiment of the present invention, the total load is a concentrated load and/or a distributed load; and
the preload applies load and/or effect direction is consistent with the effect direction of all the loads, and the preload comprises any one or combination of any more of preload, pretension, preload, tension and compression.
As an alternative implementation, in the embodiment of the present invention, the total load is q, the preload is p, and p < uq, where μ is a preload coefficient, and μ ≦ 1.
As an optional implementation manner, in the embodiment of the present invention, the directions of the first load and the second load are the same as the directions of all the loads.
As an alternative implementation manner, in an embodiment of the present invention, the connection state of the first support is adjusted from the original connection state to a first connection state, the original connection state of the second support is maintained unchanged or constraint rigidity is increased to be strengthened, and before the first load and preload are applied to the torsion member, the method further includes:
calculating the difference of the internal forces of the first support and the second support according to the internal forces of the first support and the second support in the original connection state;
and calculating the values of the first load and the preload according to the internal force difference and the total load.
As an alternative implementation, in an embodiment of the present invention, before the adjusting the connection state of the first support from the first connection state to the second connection state, the removing the preload and applying the second load on the torsion member, the method further includes:
and calculating the value of the second load according to the calculated first load and all the calculated loads.
Compared with the prior art, the method for calculating the loading and the pre-internal force of the torsion member has the following beneficial effects:
the invention provides a method for loading a torsion member and calculating a pre-internal force, which is characterized in that supports with larger internal force of the torsion member are connected in stages and the load is applied in stages, so that the internal force of the torsion member is homogenized. And because the preload is applied and removed in stages to provide the internal force for the torsion member, the internal force further reduces the amplitude and the unevenness of the internal force generated by the load on the torsion member, thereby improving the stress performance of the torsion member in the structure and improving the rationality and the economy of the torsion member in the structure.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a flowchart of a method for loading a torsion member and calculating a pre-internal force according to an embodiment of the present invention;
fig. 2 is a graph of internal force torque applied to a torsion member in a fully loaded condition with its mountings in their original connected condition in accordance with an embodiment of the invention;
fig. 3 is a graph of internal force torque applied to a first seat of a torsion member adjusted to a first connection state and applying a first load in accordance with a first embodiment of the present invention;
FIG. 4 is a graph of internal force torque with a first seat of a torsion member adjusted to a first connection state and applying a preload in a first embodiment of the invention;
FIG. 5 is a graph of internal force torque with the first seat of the torsion member adjusted to the second connection state and with preload removed in case one embodiment of the present invention;
fig. 6 is a graph of internal force torque with the first seat of the torsion member adjusted to the second connection state and applying a second load in case one of the embodiments of the present invention;
FIG. 7 is a graph of internal force torque of FIGS. 3 and 6 after superposition of the torques;
FIG. 8 is a graph of the torque of FIG. 4 and FIG. 5 superimposed on the torque of the pre-internal force;
FIG. 9 is a graph of internal force torque of FIGS. 7 and 8 after superposition of the torques;
fig. 10 is a graph of internal force torque with the first seat of the torsion member adjusted to the first connection state and applied preload in case two of the embodiment of the present invention;
fig. 11 is a graph of internal force torque with the first seat of the torsion member adjusted to the second connection state and with preload removed in case two of the embodiment of the present invention;
FIG. 12 is a graph of the torque of FIG. 10 and FIG. 11 superimposed on the torque of the pre-internal force;
fig. 13 is an internal force torque diagram of fig. 7 and 12 with the torques superimposed.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the present invention, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "center", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are used primarily to better describe the invention and its embodiments and are not intended to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.
Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meanings of these terms in the present invention can be understood by those skilled in the art as appropriate.
Furthermore, the terms "mounted," "disposed," "provided," "connected," and "connected" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.
Furthermore, the terms "first," "second," and the like, are used primarily to distinguish one device, element, or component from another (the specific nature and configuration may be the same or different), and are not used to indicate or imply the relative importance or number of the indicated devices, elements, or components. "plurality" means two or more unless otherwise specified.
The invention discloses a method for calculating the loading and the pre-internal force of a twisted member, which plays a role in doubly homogenizing the internal force of the twisted member by the connected state division, the load division application and the preload division application and removal, and improves the rationality and the economy of the twisted member in the structure.
The technical solution of the present invention will be further described with reference to the following embodiments and the accompanying drawings.
The embodiment of the invention discloses a method for loading a torsion member and calculating a pre-internal force, and please refer to fig. 1, wherein fig. 1 is a schematic flow chart of the method for loading the torsion member and calculating the pre-internal force disclosed by the embodiment of the invention. As shown in fig. 1, a method for calculating a loading and pre-internal force of a torsion member may include:
101. the total load to which the torsion member is subjected when its support is in the original connected state is calculated.
In this embodiment, the torsion member mainly refers to a member that bears torque, such as a column, a wall, a beam, and the like, wherein the beam may include a single-span beam, a multi-span continuous beam, a floor beam, a wall beam, a structural beam, and the like. The original connection state in this embodiment includes, but is not limited to, any one of a hinged connection, a semi-rigid connection, or a rigid connection, since the torsion member is subjected to a torque in either a partially constrained or fully constrained state.
Further, the entire load of the torsion member mainly includes a constant load and a live load. Specifically, the constant load includes the self weight of the structure, the floor laminated layer, the floor surface layer, and the like, and is determined by engineering and structural methods. Live loads include loads of personnel, equipment, etc., as determined by engineering functions. That is, the constant load is generated by the project itself and the live load is generated by the user. Of course, under the influence of environmental factors, the twisted member may also be subjected to dynamic loads such as wind loads and earthquake loads. In the theory of structural engineering, the specific values of these types of loads to which the torsion member is subjected can be calculated according to the formula specified in the engineering specification.
102. And determining the internal force of the first support and the second support of the torsion member in the original connection state according to all the loads, wherein the internal force of the first support is greater than that of the second support under the action of all the loads.
In the embodiment, the internal force is homogenized mainly by connecting the seat nodes with larger internal force in the traditional torsion member in stages, and the internal force under the action of partial load torque is necessarily completely or partially transferred to the other end, so that the smaller internal force at the other end of the traditional member is increased. Therefore, a seat having a large internal force in the torsion member needs to be determined first.
The following description will take a single-span torsion member with two fixed ends for bearing a half-span uniform torque load as an example.
As shown in fig. 2, a torsion member having a length L is taken as an example. The two ends of the single-span torsion member are fixedly supported, and the internal force and torque load q is uniformly distributed in the half spantUnder the action, the generated full span internal force torque graph is in the zigzag linear distribution of positive and negative opposite signs of internal force torques at two ends. The opposite sign point is positioned at the approximate full span midpoint in the half span section acted by the internal force torque load. That is, the internal force torque of the half span acted by the internal force torque load is distributed in a diagonal line intersecting with the rod shaft, and the other half span is distributed in a constant straight line.
The internal force and torque of the first support A are as follows:
the internal force torque of the second support B is as follows:
the total span internal force torque generated by the first support a is the maximum peak value and is equal to 3 times of the internal force torque of the second support B, that is, the internal force torque of the first support a is greater than that of the second support B, so the embodiment takes the first support a as a support connected in stages as an example for illustration.
103. And adjusting the connection state of the first support from the original connection state to the first connection state, keeping the original connection state of the second support unchanged, and applying a first load and preload on the torsion member.
In this embodiment, based on the basic theory that the distribution of the internal force of the node with large rigidity is large and the distribution of the internal force of the node with small rigidity is small, the invention adopts the support nodes with large internal force to be connected in stages, and the first connection state is the initial connection state of the stage connection, so that the connection rigidity of the first support A in the first connection state is less than that of the first support A in the original connection state, and the internal force torque under the preloading action can be transferred to the second support B with large rigidity in the stage connection, thereby increasing the internal force torque of the second support B.
Further, since the connection state of the torsion member mainly includes 4 types, i.e., a cantilever state, a hinge state, a semi-rigid connection state, or a rigid connection state, in this embodiment, the first connection state and the original connection state mainly include the following cases: when the original connection state is semi-rigid connection, the first connection state is a cantilever state, or when the original connection state is semi-rigid connection, the first connection state is hinged, or when the original connection state is rigid connection, the first connection state is semi-rigid connection.
Specifically, when the original connection state is a semi-rigid connection state and the first connection state is a cantilever state, the first support A is adjusted to be in the cantilever state from the traditional semi-rigid connection state, and the second support B is kept unchanged in the traditional semi-rigid connection state or reinforced by increasing constraint rigidity; when the original connection state is a rigid connection state and the first connection state is a cantilever state, the first support A is adjusted to be in the cantilever state from the traditional rigid connection state, and the rigid connection state of the traditional connection of the second support B is kept unchanged or constraint rigidity is increased for reinforcement; when the original connection state is semi-rigid connection and the first connection state is hinged connection, the first support A is adjusted to be hinged connection from the semi-rigid connection of the traditional connection, and the second support B is kept unchanged or restrained rigidity is increased for reinforcement; when the original connection state is rigid connection and the first connection state is hinged connection, the first support A is adjusted to be hinged connection from the rigid connection of the traditional connection, and the rigid connection state of the traditional connection of the second support B is kept unchanged or constraint rigidity is increased for reinforcement; when the original connection state is rigid connection and the first connection state is semi-rigid connection, the rigid connection of the traditional connection of the first support A is adjusted to be semi-rigid connection, and the second support B is kept unchanged in the traditional rigid connection state or restrained rigidity is increased for reinforcement.
In this embodiment, the degree of internal force homogenization of the torsion member depends on the degree of internal force torque transfer, which depends on the relative proportions of the stiffness of the two states and the relative proportions of the loads of the two stages. Adjusting the connection state of the first support from the original connection state to the first connection state, maintaining the original connection state of the second support unchanged or increasing the constraint rigidity for reinforcement, and before applying the first load and preload on the torsion member, the method further comprises:
1031. and calculating the difference of the internal forces of the first support and the second support according to the internal forces of the first support and the second support in the original connection state.
1032. And calculating values of the first load and the preload according to the internal force difference and all the loads.
In this embodiment, the total load is a concentrated load and/or a distributed load, and the preload is basically defined as a pre-applied load in accordance with the direction and distribution of the load, such as pre-stacking and pre-mounting. Preload is broadly defined as any load and/or effect that is pre-applied in a direction consistent with, distributed in the same direction as, or different from the direction of the load being applied. From the distribution characteristics, a distribution load and/or a concentration load is included. From the application method, the application method can be pretension force (called pretension for short), or pre-pressure force (called pre-pressure for short), pre-counter-tension, pre-counter-pressure, or other loads or actions, or the combination of several or various of the above.
The effect of the preload relief is to produce a subtractive homogenization of the torque with conventional internal forces (i.e., the internal forces of the torsion member in a conventional one-time connection and full load application manner of the torsion member construction). The degree of subtractive homogenization depends on the relative proportions of the different torsional stiffnesses of the two stage states, as well as the method of preloading, the distribution, magnitude and efficiency of the preloading, etc.
Further, assuming that the total load is q and the preload is p, the magnitude of the preload is controlled, i.e. the preload is controlled to be a certain proportion of the load, i.e. the ratio p/q of the preload to the load, and p < uq, where μ is the preload coefficient and μ ≦ 1.
104. Adjusting the connection state of the first bracket from the first connection state to the second connection state, removing the preload and applying a second load on the torsion member.
In this embodiment, the connection state of the first support a is adjusted from the first connection state to the second connection state, and the second connection state is the last connection stage of the staged connection, so it is required to satisfy that the connection stiffness of the second connection state is greater than the connection stiffness of the first connection state and is not less than the stiffness of the original connection state, and the constraint number of the second connection state is not less than the constraint number of the original connection state, wherein the second support B is divided into two cases, the first case is that the second support B is kept unchanged in the original connection state, the second case is that the second support B increases the constraint stiffness for reinforcement, and this embodiment only exemplifies that the second support B is kept unchanged in the original connection state. Namely, when the original connection state is rigid connection, the second connection state is rigid connection; when the original connection state is hinged, the second connection state is hinged or rigid connection; when the original connection state is semi-rigid connection, the second connection state is semi-rigid connection or rigid connection; when the original connection state is hinged, the second connection state is hinged or rigid. This embodiment is exemplified by only the case where the constraint number of the second connection state is equal to the constraint number of the original connection state.
Specifically, the first support a is adjusted from a cantilever state to a semi-rigid connection, or the first support a is adjusted from a cantilever state to a rigid connection, or the first support a is adjusted from a hinge to a semi-rigid connection, or the first support a is adjusted from a hinge to a rigid connection, or the first support a is adjusted from a semi-rigid connection to a rigid connection. In the original connection state and the second connection state, since the connection state of the first support a is the same as the connection state of the second support B, that is, the connection rigidity of the second support B is equal to the connection rigidity of the first support a.
Further, removing the preload, which corresponds to applying a load of equal magnitude and opposite direction to the preload, may be referred to as "reverse preload", which generates an internal force in a direction substantially opposite to that of the conventional internal force, and which dampens the internal force of the homogenizing torsion member. The preload of the first connection state is superimposed with the unload of the second connection state, the preload unload being zeroed, i.e. the reverse preload cancels out the preload to zero. Although the directions of the internal forces generated by the preload and unload are mainly opposite in different states, the magnitude distributions are completely different and thus cannot be completely cancelled. The internal force remaining after partial cancellation in the stack is pre-established before partial loading and is referred to as the "pre-internal force".
For example, taking the pre-load as the pre-load, when the pre-load is removed, a force with the same magnitude as the pre-load and the opposite direction can be added to the torsion member, for example, if the pre-load is vertical downward, a tensile force with an upward direction can be applied to exactly offset the magnitude of the pre-load.
In this embodiment, before adjusting the connection state of the first bracket from the first connection state to the second connection state, removing the preload, and applying the second load to the torsion member, the method further comprises:
and calculating the value of the second load according to the calculated first load and all the loads.
In this embodiment, the sum of the first load and the second load is equal to the total load. The direction of the first load and the second load is the same as the direction of all the loads.
Preferably, the first load and the second load are applied to an end of the torsion member near the first mount. It will be appreciated that the location of the preload distribution is load dependent and therefore the preload distribution is not limited to either end and the location of application may be selected as a practical matter and is not limited thereto.
105. The internal force of the first support and the internal force of the second support in the first connection state are calculated respectively based on the applied first load and the applied preload, the internal force of the first support and the internal force of the second support in the second connection state are calculated respectively based on the unloaded preload and the applied second load, the internal force of the first support in the first connection state and the internal force of the second support in the second connection state are superposed to obtain the target internal force of the first support, and the internal force of the second support in the first connection state and the internal force of the second support in the second connection state are superposed to obtain the target internal force of the second support.
In the present embodiment, since the first mount a is adjusted from the original connection state to the first connection state, and the original connection state of the second mount B remains unchanged, that is, the connection stiffness of the second mount B is greater than that of the first mount a. Thus, after the application of the first load, the internal force torque of the second abutment B increases (compare fig. 2 and 3) with respect to the way in which the one-time connection applies the full load, i.e. a partial internal force torque transfer from the first abutment a to the second abutment B is achieved. Also, since the preload is applied in the first connection state, a preload internal force torque is generated in the torsion member.
Further, after the first support A is adjusted from the first connection state to the second connection state, the second connection state is the same as the original connection state, and therefore, after the preloading is removed, the unloading generates the torque which can fully reduce the traditional internal force. The different states of preload and unload, from preload to unload, result in a structure that produces a "pre-internal torque" that is advantageous for damping conventional internal torque. In addition, after the second load is applied, the internal force torque generated under the action of the internal force torque of the second load is the same as the internal force torque generated in the traditional structure, and the internal force torque is not transferred.
The following will describe in detail the calculation process of the internal force (internal force torque as an example) of the torsion member of the present invention with reference to the examples and drawings:
case one: the preloading type internal force preloading method.
Connecting the first supports A with larger internal force and torque of the torsion member in the figure 2 in stages to form a state-divided torsion member, and connecting all loads qtDivided into a first load qt1And a second load qt2The two parts are applied in stages and a preload internal force measure is applied.
As shown in fig. 3, in the first stage, the first support a of the torsion member is adjusted to the first connection state of temporary disconnection to form a state of one end being fixed to one end of the cantilever, and a first load q is appliedt1. The internal force torque chart is in a half-span oblique line and half-span horizontal straight line and is distributed in a full-span negative broken line shape.
The internal force and torque of the first support A are as follows:
TA1＝0
the internal force torque of the second support B is as follows:
as shown in FIG. 4, in the first-stage connected state, a half-span torque preload p is applied to the torsion memberstAnd generating a preload internal force torque. Wherein the content of the first and second substances,
the preload internal force torque of the first support A is as follows:
TAp＝0
the preload internal force torque of the second support B is as follows:
as shown in fig. 5, in the second stage, the first support a of the torsion member is adjusted to the second connection state, so as to form the conventional two-end fixed state. In the second connection state, the preload p is unloadedtCorresponding to the application and preload of uniform torque ptEqual and opposite unloading p'tThe internal force in the direction completely opposite to that of the traditional internal force is generated, and the internal force of the torsion member can be completely reduced. Although the directions of the internal forces generated by the preload and unload are mainly opposite in different states, the magnitude distributions are completely different and thus cannot be completely cancelled. And the residual internal force after partial cancellation in the superposition is the 'preloaded type internal force' of the torsion member.
Wherein the content of the first and second substances,
the unloading internal force torque of the first support A is as follows:
the unloading internal force torque of the second support B is as follows:
as shown in fig. 6, in the second connection state,applying a second load qt2. Wherein the content of the first and second substances,
the internal force and torque of the first support A are as follows:
the internal force torque of the second support B is as follows:
as shown in fig. 7, the loading effect of the two stages (fig. 3) and (fig. 6) is superimposed by using the superposition principle of the structure theory, and a full-load internal force torque diagram is obtained. Wherein the content of the first and second substances,
the full-load internal force torque of the first support A is as follows:
the full-load internal force torque of the second support B is as follows:
the internal force torques of the first support A and the second support B calculated by the two formulas are internal force torques obtained after the torsion member adopts the staged connection and staged load application of the invention, and compared with the traditional connection and load application mode of the torsion member, the internal force torque of the first support A is reduced
Internal force torque of the second support B is increased
I.e. a partial internal force torque of the first abutment a is transferred to the second abutment B with a transfer amplitude of
The damping and the homogenization of the force and the torque in the torsion member are realized.
As shown in fig. 8, the preload (fig. 4) and unload (fig. 5) effects are superimposed to produce a map of the torque of the preload force produced by the preload force measure. Wherein the content of the first and second substances,
the torque of the internal force of the first support A is as follows:
the torque of the internal force of the second support B is as follows:
the diagram of the torque of the internal force generated by connecting the torsion members in stages shows that the torque of the internal force can reduce the peak value of the amplitude of the traditional internal force torque and increase the small value.
As shown in fig. 9, the full load (fig. 7) effect is superimposed with the preload (fig. 8) to obtain a torque-internal force diagram of the torsion member by the combined action of staged loading and preload. Wherein the content of the first and second substances,
the internal force and torque of the first support A are as follows:
the internal force torque of the second support B is as follows:
the calculation of the two formulas shows that the effect of the large value reduction, the small value increase, the peak value reduction and the full span homogenization of the internal force torque of the first support A and the second support B is more obvious under the action of applying load and applying pre-internal force in stages.
When in use
When the temperature of the water is higher than the set temperature,
namely when
When the method is used, the peak value of the internal force torque is reduced by 1/3 compared with the traditional method, and a good reduction and homogenization effect is achieved.
Case two: pretensioning type internal force pretensioning method.
The basic condition of the torsion member and the full-load internal force torque are the same as the preloading method, and only the preloading distribution torque is changed into the pretension concentrated torque.
As shown in fig. 10, in the first connection state, a mid-span pretension-concentrating torque P is applied to the torsion membertAnd generating the pre-internal force torque. Wherein the content of the first and second substances,
the preload internal force torque of the first support A is as follows:
TAP＝0
the preload internal force torque of the second support B is as follows:
TBP＝-Pt
in the second stage, as shown in fig. 11, the first support A of the torsion member is adjusted to the second connection state, and the pre-tension concentration torque P is removedtCalled relaxation, corresponding to the application and pretensioning of a concentrated torque PtP 'with equal size and opposite direction'tThe internal force in the direction completely opposite to that of the traditional internal force is generated, and the internal force of the torsion member can be completely reduced. Although the internal forces generated by the preload and unload are mainly shown in opposite directions under different conditions, the magnitude distributions are completely different and thus are not completely cancelled. The residual internal force after partial cancellation in the superposition is the pre-tensioning pre-internal force of the torsion member. Wherein the content of the first and second substances,
the unloading internal force torque of the first support A is as follows:
the unloading internal force torque of the second support B is as follows:
as shown in FIG. 12, the pretensioning (FIG. 10) and the relaxation (FIG. 11) effects are superposed to obtain a pretensioning force diagram generated by the pretensioning type pretensioning force measure, which is in a full span uniform distribution rule. The full span pretensioning type internal force torque is as follows:
therefore, the pre-tensioning type pre-internal force method plays a role in full span reduction and homogenization on the traditional internal force torque amplitude.
As shown in fig. 13, the full load effect (fig. 7) and the pre-internal force effect (fig. 12) are superimposed to obtain an internal force torque diagram of the pre-tensioned pre-internal force binary structure. Wherein the content of the first and second substances,
the internal force and torque of the first support A are as follows:
the torque of the internal force of the second support B is as follows:
the above formula shows that the pretensioning type pretensioning force has the homogenization effect similar to the preloading type. When the measures are reasonable, the ideal effects of best reduction and homogenization and easiest implementation can be achieved.
By adopting the scheme of the invention, the invention has the following beneficial effects:
1. the control internal force torque is reduced by 10 to 30 percent compared with the control internal force torque analyzed by the traditional theory
2. The internal force torque of the support is reduced, the peak value is reduced, the two ends are homogenized, the cross sections of the support connecting devices at the two ends or the support components at the two ends can be unified, the standardization is facilitated, the materials are saved, and the manufacturing and the installation are convenient.
The embodiment of the invention provides a method for loading a torsion member and calculating a pre-internal force, which is characterized in that supports with larger internal force of the torsion member are connected in stages and the load is applied in stages, so that the internal force of the torsion member is reduced and homogenized. And because the pre-internal force is provided for the torsion member by jointly adopting the application and the removal of the preload, the pre-internal force further reduces the unevenness of the internal force generated by the load on the torsion member, thereby improving the stress performance of the torsion member in the structure and improving the rationality and the economy of the torsion member in the structure.
The above detailed description is provided for the method for calculating the loading and pre-internal force of the torsion member disclosed in the embodiment of the present invention, and the principle and the implementation manner of the present invention are explained by applying a specific example, and the description of the above embodiment is only used to help understanding the method for calculating the loading and pre-internal force of the torsion member of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (8)
1. A method of loading a torsion member and calculating a pre-internal force, the method comprising:
calculating all loads borne by the torsion member when the support of the torsion member is in an original connection state;
determining the internal force of a first support and a second support of the torsion member in the original connection state according to the total load, wherein the internal force of the first support is greater than that of the second support under the action of the total load;
adjusting the connection state of the first support from the original connection state to a first connection state, keeping the original connection state of the second support unchanged or increasing constraint rigidity to strengthen, and applying a first load and preload on the torsion member;
adjusting the connection state of the first mount from the first connection state to a second connection state, removing the preload and applying a second load on the torsion member;
respectively calculating internal forces of the first support and the second support in the first connection state based on the applied first load and the applied preload, respectively calculating internal forces of the first support and the second support in the second connection state based on the unloaded preload and the applied second load, superposing the internal forces of the first support in the first connection state and the second connection state to obtain a first support target internal force, and superposing the internal forces of the second support in the first connection state and the second connection state to obtain a second support target internal force;
wherein the sum of the first load and the second load is equal to the total load.
2. The method of claim 1, wherein a connection stiffness of the first mount in both the original connection state and the second connection state is greater than a connection stiffness of the first mount in the first connection state.
3. The method of claim 2, wherein the original connection state is hinged, semi-rigid, or rigid, the first connection state is cantilevered, hinged, semi-rigid, or rigid, and the second connection state has a constraint number that is not less than the constraint number of the original connection state.
4. A method according to claim 2 or 3, characterized in that the total load is a concentrated load and/or a distributed load; and
the preload applies load and/or effect direction is consistent with the effect direction of all the loads, and the preload comprises any one or combination of any more of preload, pretension, preload, tension and compression.
5. The method of claim 4, wherein the total load is q, the preload is p, and p < uq, where μ is the preload factor and μ ≦ 1.
6. A method according to any one of claims 1 to 3, wherein the direction of the first and second loads is the same as the direction of the total load.
7. A method according to any one of claims 1 to 3, wherein adjusting the connection state of the first mount from the original connection state to a first connection state, the original connection state of the second mount being maintained or reinforced with increased constraint stiffness, the method further comprising, prior to applying a first load and preload on the torsion member:
calculating the difference of the internal forces of the first support and the second support according to the internal forces of the first support and the second support in the original connection state;
and calculating the values of the first load and the preload according to the internal force difference and the total load.
8. The method of claim 7, wherein prior to adjusting the connection state of the first mount from the first connection state to the second connection state, removing the preload, and applying a second load on the torsion member, the method further comprises:
and calculating the value of the second load according to the calculated first load and all the calculated loads.
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