A method and device for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam

Abstract

The present invention discloses a method and device for simulating the joint loading of uniformly distributed load and concentrated load on a simply supported beam, comprising: before the simulation test, according to the maximum theoretical deflection of the simply supported beam specimen under the joint action of uniformly distributed load and concentrated load, the minimum stiffness of the spring and the stiffness distribution coefficient of the springs distributed along the distribution beam are determined, and then a number of springs with different stiffnesses are arranged at the bottom of the distribution beam according to the stiffness distribution coefficient to form a spring distribution beam for testing the simply supported beam specimen; during the simulation test, a uniformly distributed load is applied to one side of the simply supported beam specimen through the spring distribution beam, and at the same time, a concentrated load is applied to the other side of the simply supported beam specimen. The present invention evenly distributes the load provided by the uniformly distributed load servo hydraulic jack to the simply supported beam specimen through the designed spring distribution beam, and then uses the concentrated load servo hydraulic jack to simulate the concentrated load to collaboratively complete the load form simulation of the joint action of the uniformly distributed load and the concentrated load on the simply supported beam specimen.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering structure testing, and in particular to a method and a device for simulating the joint loading of uniformly distributed loads and concentrated loads on a simply supported beam. Background Art

[0002] In civil engineering structures, simply supported beams are a common structural member. Uniformly distributed loads and concentrated loads acting on simply supported beams are also common forms of loads, such as the force form of the main beam in the frame structure. At present, the bending test of the main beam mainly adopts the four-point loading method. The defects of this method are: ignoring the effect of uniformly distributed loads and simplifying the two concentrated loads to equal sizes. Under normal circumstances, the four-point loading method basically meets the conditions, but if the uniformly distributed load cannot be ignored, then when the two concentrated loads are not equal, the four-point loading method is no longer applicable. Summary of the invention

[0003] To this end, the technical problem to be solved by the present invention is to overcome the defects in the prior art. According to the stress state of a simply supported beam under the joint action of uniformly distributed load and concentrated load when the uniformly distributed load cannot be ignored and when unequal concentrated forces act together, a method and device for simulating the joint loading of uniformly distributed load and concentrated load on a simply supported beam are provided to realize the loading simulation of the main beam under the joint action of uniformly distributed load and concentrated load and under unequal concentrated load.

[0004] In order to solve the above technical problems, the present invention provides a method for simulating the co-loading of uniformly distributed load and concentrated load on a simply supported beam, comprising:

[0005] Before the simulation test, the maximum theoretical deflection of the simply supported beam specimen to be tested under the combined action of uniformly distributed load and concentrated load is obtained;

[0006] According to the maximum theoretical deflection of the simply supported beam specimen, the minimum stiffness of the spring and the stiffness distribution coefficient of the springs distributed along the distribution beam are determined;

[0007] According to the stiffness distribution coefficient of the spring along the distribution beam, a plurality of springs with different stiffnesses are arranged at the bottom of the distribution beam according to the stiffness distribution coefficient to form a spring distribution beam for testing the simply supported beam specimen;

[0008] Among them, the minimum stiffness of the spring is

[0009]

[0010] Where, E is the elastic modulus of the simply supported beam specimen, I is the section moment of inertia of the simply supported beam specimen, δ max is the relative displacement coefficient of the maximum position along the span direction of the simply supported beam specimen, η is the load concentration coefficient, and ζ is the equivalent load coefficient;

[0011] The stiffness distribution coefficient of the spring distributed along the distribution beam is

[0012]

[0013] In the formula, k i is the spring stiffness required at different positions, δ i is the relative displacement coefficient at different positions along the span direction of the simply supported beam specimen, δ max is the relative displacement coefficient at the maximum position along the span direction of the simply supported beam specimen;

[0014] As a preferred embodiment of the present invention, the step of obtaining the maximum theoretical deflection of the simply supported beam specimen under the combined action of a uniformly distributed load and a concentrated load comprises:

[0015] According to the span of the simply supported beam specimen and the size of the uniformly distributed load, the bending moment distribution of the simply supported beam specimen under the uniformly distributed load is obtained; according to the span of the simply supported beam specimen and the size of a single concentrated load, the bending moment distribution of the simply supported beam specimen under the single concentrated load is obtained; according to the span of the simply supported beam specimen and the sizes of two concentrated loads, the bending moment distribution of the simply supported beam specimen under the two concentrated loads is obtained;

[0016] The uniform load deflection curve formula is obtained according to the bending moment distribution under the uniform load; the single concentrated load deflection curve formula is obtained according to the bending moment distribution under the single concentrated load; the two concentrated load deflection curve formulas are obtained according to the bending moment distribution under the two concentrated loads;

[0017] Substitute the parameters of the simply supported beam specimen at different positions into the uniformly distributed load deflection curve formula, the single

[0018] The theoretical deflection coefficients χ at different positions along the span direction of the simply supported beam specimen under the action of uniformly distributed load, single concentrated load, and two concentrated loads are obtained from the concentrated load deflection curve formula and the two concentrated load deflection curve formula. i , see Table 1,

[0019] Table 1. Deflection coefficient χ under different load forms i

[0020]

[0021] As a preferred embodiment of the present invention, the step of determining the minimum stiffness of the spring comprises:

[0022] According to the theoretical deflection coefficients under uniform load, single concentrated load and two concentrated loads, the deflection formula w of the simply supported beam specimen under the combined action of uniform load and concentrated load is obtained: i for

[0023]

[0024] Where q is the uniform load, l is the span of the simply supported beam specimen, and χ i The deflection distribution coefficient when uniformly distributed load and concentrated load are used together;

[0025] According to the deflection formula of the simply supported beam specimen under the combined action of uniformly distributed load and concentrated load and Hooke's law, the stiffness k of the spring required at different positions of the simply supported beam specimen is obtained: i for

[0026]

[0027] and the minimum stiffness k of the spring min , where δ i is the relative displacement coefficient at different positions along the span direction of the beam, i is 0, 1 / 10, 2 / 10, 3 / 10, 4 / 10, 5 / 10, 6 / 10, 7 / 10, 8 / 10, 9 / 10, and 1.

[0028] As a preferred embodiment of the present invention, the step of determining the stiffness distribution coefficient of the springs distributed along the distribution beam comprises:

[0029] According to the deflection w of the simply supported beam specimen under the combined action of uniformly distributed load and concentrated load i , determine the deflection of the simply supported beam specimen at different positions under the combined action of uniformly distributed load and concentrated load;

[0030] According to the relative displacement coefficient δ at different positions i And the following formula

[0031]

[0032] Determine the stiffness distribution coefficient of the spring along the distribution beam, see Table 4,

[0033] Table 4. Distribution coefficient of spring stiffness along the span of simply supported beam specimen

[0034]

[0035] When the simply supported beam specimens with different spans are tested, the spring stiffness coefficient is given by linear interpolation according to Table 4.

[0036] As a preferred embodiment of the present invention, the deflection coefficient under different load forms can be obtained by multiplying the deflection coefficient under uniform load by the unit load concentration coefficient, that is,

[0037] χ i 集中荷载 =ηχ i均布荷载 ,

[0038] Among them, under the action of uniformly distributed load, the load concentration coefficient η is 1; under the action of one concentrated load, the load concentration coefficient η is 1.57; under the action of two concentrated loads, the load concentration coefficient η is 1.35; under the action of three concentrated loads, the load concentration coefficient η is 1.27.

[0039] As a preferred embodiment of the present invention, the equivalent load coefficient ζ is

[0040]

[0041] Where p is the total value of concentrated load.

[0042] As a preferred embodiment of the present invention, during the simulation test, the spring distribution beam is placed on the simply supported beam specimen, and the spring is in conflict with the simply supported beam specimen; a load is applied to the distribution beam of the spring distribution beam, and the spring distribution beam converts the load it receives into a uniformly distributed load, and applies a uniformly distributed load to one side of the simply supported beam specimen through the spring, and at the same time, a concentrated load is applied to the other side of the simply supported beam specimen.

[0043] A device for simulating the co-loading of uniformly distributed load and concentrated load on a simply supported beam, and a method for simulating the co-loading of uniformly distributed load and concentrated load on a simply supported beam as described in any one of the above items, using the device to complete the test, comprising:

[0044] A support, on which the simply supported beam specimen is placed;

[0045] A spring distribution beam comprises a distribution beam and a plurality of springs of different stiffness arranged at equal intervals at the bottom of the distribution beam, wherein the spring distribution beam is placed on the simply supported beam specimen, and the springs are in contact with the upper surface of the simply supported beam specimen; the minimum stiffness of the springs and the stiffness distribution coefficient of the springs distributed along the distribution beam are determined by the maximum theoretical deflection of the simply supported beam specimen under the combined action of a uniformly distributed load and a concentrated load; the springs are distributed along the distribution beam with a stiffness that is larger in the middle and smaller at both ends

[0046] Among them, the minimum stiffness of the spring is

[0047]

[0048] Where, E is the elastic modulus of the simply supported beam specimen, I is the section moment of inertia of the simply supported beam specimen, δ max is the relative displacement coefficient of the maximum position along the span direction of the simply supported beam specimen, η is the load concentration coefficient, and ζ is the equivalent load coefficient;

[0049] The stiffness distribution coefficient of the spring distributed along the distribution beam is

[0050]

[0051] In the formula, k i is the spring stiffness required at different positions, δ i is the relative displacement coefficient at different positions along the span direction of the beam, δ max is the relative displacement coefficient at the maximum position along the span direction of the beam;

[0052] A uniformly distributed load servo hydraulic jack is arranged above the spring distribution beam, and applies a downward load to the spring distribution beam. The distribution beam and the spring convert the load into a uniformly distributed load and apply it to the simply supported beam specimen;

[0053] The concentrated load servo hydraulic jack is arranged below the simply supported beam specimen and applies an upward concentrated load to the simply supported beam specimen.

[0054] As a preferred embodiment of the present invention, it also includes:

[0055] A plurality of force sensors are provided for respectively monitoring the uniform load servo hydraulic jack and the force applied by the uniform load servo hydraulic jack;

[0056] A reaction floor, the concentrated load servo hydraulic jack being connected to the reaction floor;

[0057] A reaction frame is erected on the reaction floor, and a self-balancing system is formed between the reaction frame and the reaction floor; the uniformly distributed load servo hydraulic jack is connected to the reaction frame.

[0058] As a preferred embodiment of the present invention, the number of the concentrated load servo hydraulic jacks is one, two or three.

[0059] The above technical solution of the present invention has the following advantages compared with the prior art:

[0060] The method and device for simulating the joint loading of uniformly distributed load and concentrated load on a simply supported beam described in the present invention designs a spring distribution beam by combining a distribution beam and a spring, converts the load provided by the uniformly distributed load servo hydraulic jack into a uniformly distributed load and applies it to the simply supported beam specimen, and cooperates with the concentrated load servo hydraulic jack to collaboratively complete the load simulation of the joint action of the uniformly distributed load and concentrated load on the simply supported beam specimen.

[0061] The spring used in the spring distribution beam is determined according to the maximum theoretical deflection of the simply supported beam specimen under the combined action of uniformly distributed load and concentrated load. When testing simply supported beam specimens of different spans, different spring distribution beams are designed and used so as to be able to complete the load simulation of the combined action of uniformly distributed load and concentrated load in a targeted manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0063] Figure 1 The present invention is a workflow diagram of a method for simulating the joint loading of a simply supported beam with uniformly distributed load and concentrated load.

[0064] Figure 2 It is a schematic diagram of a simulation device for co-loading a uniformly distributed load and a concentrated load on a simply supported beam of the present invention.

[0065] Explanation of the reference numerals in the drawings in the specification: 1. reaction floor; 2. support; 3. reaction frame; 4. force sensor; 51. concentrated load servo hydraulic jack; 52. uniform load servo hydraulic jack; 6. spring distribution beam; 61. distribution beam; 62. spring; 7. simply supported beam specimen. DETAILED DESCRIPTION

[0066] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0067] In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "second" and "first" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0068] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] Unless otherwise expressly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In addition, the term "comprising" is intended to cover non-exclusive inclusions, such as a process, method, system, product or device that includes a series of steps or units, is not limited to the listed steps or units but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0070] Embodiment 1

[0071] Reference Figures 1-2 As shown, an embodiment of a method for simulating the simultaneous loading of uniformly distributed load and concentrated load on a simply supported beam of the present invention comprises:

[0072] Before the simulation test, the maximum theoretical deflection of the simply supported beam specimen 7 to be tested under the combined action of a uniformly distributed load and a concentrated load is obtained;

[0073] According to the maximum theoretical deflection of the simply supported beam specimen 7, the minimum stiffness of the spring 62 and the stiffness distribution coefficient of the spring 62 distributed along the distribution beam 61 are determined;

[0074] According to the stiffness distribution coefficient of the spring 62 along the distribution beam 61, a plurality of the springs 62 are arranged at the bottom of the distribution beam 61 according to the stiffness distribution coefficient to form a spring distribution beam 6 for testing the simply supported beam specimen 7;

[0075] Among them, the minimum stiffness of the spring 62 is

[0076]

[0077] Where, E is the elastic modulus of the simply supported beam specimen 7, I is the section inertia moment of the simply supported beam specimen 7, δ max is the relative displacement coefficient of the maximum position along the span direction of the simply supported beam specimen, η is the load concentration coefficient, and ζ is the equivalent load coefficient;

[0078] The stiffness distribution coefficient of the spring 62 distributed along the distribution beam 61 is:

[0079]

[0080] In the formula, k i is the spring 62 stiffness required at different positions, δ i is the relative displacement coefficient at different positions along the span direction of the beam, δ max is the relative displacement coefficient at the maximum position along the span direction of the beam;

[0081] During the simulation test, the spring distribution beam 6 is placed on the simply supported beam specimen 7, and the spring 62 is in conflict with the simply supported beam specimen 7; a load is applied to the distribution beam 61 of the spring distribution beam 6, and the spring distribution beam 6 converts the load it receives into a uniformly distributed load, and applies a uniformly distributed load to one side of the simply supported beam specimen 7 through the spring 62, and at the same time, a concentrated load is applied to the other side of the simply supported beam specimen 7.

[0082] Specifically, the steps of obtaining the maximum theoretical deflection of the simply supported beam specimen 7 under the combined action of a uniformly distributed load and a concentrated load include:

[0083] According to the span of the simply supported beam specimen 7 and the size of the uniformly distributed load, the bending moment distribution of the simply supported beam specimen 7 under the uniformly distributed load is obtained.

[0084] According to the span of the simply supported beam specimen 7 and the size of a single concentrated load, the bending moment distribution of the simply supported beam specimen 7 under the action of a single concentrated load is obtained; according to the span of the simply supported beam specimen 7 and the sizes of two concentrated loads, the bending moment distribution of the simply supported beam specimen 7 under the action of two concentrated loads is obtained.

[0085] The uniform load deflection curve formula is obtained according to the bending moment distribution under the uniform load; the single concentrated load deflection curve formula is obtained according to the bending moment distribution under the single concentrated load; and the two concentrated load deflection curve formulas are obtained according to the bending moment distribution under the two concentrated loads.

[0086] The parameters at different positions of the simply supported beam specimen 7 are respectively substituted into the uniformly distributed load deflection curve formula, the single concentrated load deflection curve formula, and the two concentrated load deflection curve formula to obtain the theoretical deflection coefficients at different positions along the span direction of the simply supported beam specimen 7 under the action of uniformly distributed load, single concentrated load, and two concentrated loads.

[0087] S101: The bending moment of the simply supported beam specimen 7 under the uniformly distributed load is distributed along the simply supported beam specimen 7 as follows:

[0088]

[0089] Where M is the bending moment, q is the uniformly distributed load, and l is the span of the simply supported beam specimen 7.

[0090] S102: From material mechanics, we know that the deflection curve and bending moment satisfy the equilibrium differential equation

[0091]

[0092] Wherein, E is the elastic modulus of the simply supported beam specimen 7, and I is the section moment of inertia of the simply supported beam specimen 7.

[0093] S103: Substituting equation (1) into equation (2) and solving the equilibrium differential equation and substituting the displacement boundary conditions, we can obtain the deflection curve formula of a simply supported beam under uniformly distributed load:

[0094]

[0095] S104: The bending moment of the simply supported beam specimen 7 under a single concentrated load is distributed along the simply supported beam specimen 7 as follows:

[0096]

[0097] Where p is the concentrated load size.

[0098] S105: Substituting equation (4) into equation (2) and solving the equilibrium differential equation and substituting the displacement boundary conditions, we can obtain the deflection curve formula of a simply supported beam under a single concentrated load:

[0099]

[0100] S106: The bending moment of the simply supported beam specimen 7 under the action of two concentrated loads is distributed along the simply supported beam specimen 7 as follows:

[0101]

[0102] S107: Substituting equation (6) into equation (2) and solving the equilibrium differential equation and substituting the displacement boundary conditions, we can obtain the deflection curve formula of a simply supported beam under two concentrated loads:

[0103]

[0104] S108: In order to unify with the deflection curve equation (3) under uniform load, the deflection curve equations (5) and (7) under single concentrated load and two concentrated loads are rewritten as

[0105]

[0106]

[0107] S109: respectively replace q in equation (3), As the load variable, As the deflection constant, the rest is the deflection position variable; by substituting the different position parameters of the simply supported beam specimen 7 into the deflection position variables in equations (3), (8), and (9), the theoretical deflection coefficient χ at different positions along the span direction of the simply supported beam specimen 7 can be obtained: i See Table 1.

[0108] Table 1. Deflection coefficient χ under different load forms i

[0109]

[0110] The steps for determining the minimum stiffness of spring 62 include:

[0111] According to the theoretical deflection coefficients under the action of uniformly distributed load, single concentrated load and two concentrated loads, the deflection formula of the simply supported beam specimen 7 under the combined action of uniformly distributed load and concentrated load is obtained;

[0112] According to the deflection formula of the simply supported beam specimen 7 under the combined action of uniformly distributed load and concentrated load and Hooke's law, the stiffness of the spring 62 required at different positions of the simply supported beam specimen 7 and the minimum stiffness of the spring 62 are obtained.

[0113] S110: From the distribution law of the deflection coefficients of concentrated loads and uniformly distributed loads in Table 1, it can be found that the ratio of the deflection coefficient of concentrated loads to the deflection coefficient of uniformly distributed loads is roughly linearly distributed, as shown in Table 2. The mean value of the deflection coefficient ratio of the load form is closely related to the maximum deflection coefficient at the mid-span, and is related to the degree of dispersion of the concentrated load. The more dispersed the concentrated load is, the closer the mean value of the deflection coefficient ratio is to the maximum deflection coefficient ratio at the mid-span.

[0114] Table 2. Ratio of deflection coefficient of concentrated load to deflection coefficient of uniformly distributed load

[0115]

[0116] S111: Repeat steps S101, S102, and S103 to obtain the maximum deflection expression of the mid-span under the action of three concentrated loads:

[0117]

[0118] From formula (10), we can know that the maximum deflection coefficient of the mid-span under the three concentrated loads is 0.3958, and then the ratio of the deflection coefficient of the three concentrated forces to the uniformly distributed load is 1.27.

[0119] S112: From Table 2 and formula (11), it can be seen that the deflection distribution coefficient of the concentrated load can be obtained by multiplying the deflection distribution coefficient of the uniformly distributed load by the corresponding load concentration coefficient η, see Table 3.

[0120] Table 3. Load concentration coefficient η

[0121]

[0122] S113: The deflection coefficient under different load forms can be obtained by multiplying the deflection coefficient under uniform load by the unit load concentration coefficient, that is,

[0123]

[0124] S114: The deflection of the simply supported beam specimen 7 under concentrated load is related not only to the load form but also to the magnitude of the concentrated load. To unify with the uniformly distributed load, assuming that the total magnitude of the concentrated load acting on the simply supported beam specimen 7 is p, an equivalent load coefficient ζ can be introduced, such that

[0125]

[0126] S115: The concentrated load deflection distribution coefficient can be expressed as

[0127]

[0128] S116: When uniformly distributed load and concentrated load are used together, the deflection distribution coefficient χ i Can be expressed as

[0129]

[0130] S117: Deflection w of a simply supported beam under uniformly distributed and concentrated loads i It can be expressed as the uniformly distributed load multiplied by the deflection invariant multiplied by the deflection coefficient χ i Right now

[0131]

[0132] S118: Then determine the spring stiffness k required for different positions according to Hooke's law i :

[0133]

[0134] In the formula, δ i is the relative displacement coefficient at different positions along the span direction of the simply supported beam specimen 7, i is 0, 1 / 10, 2 / 10, 3 / 10, 4 / 10, 5 / 10, 6 / 10, 7 / 10, 8 / 10, 9 / 10, 1. δ i It can be determined according to the following formula

[0135] δ i =|χ i -x max | (17)

[0136] S119: According to Hooke's law, the minimum spring stiffness required is

[0137]

[0138] The step of determining the stiffness distribution coefficient of the spring 62 distributed along the distribution beam 61 includes:

[0139] According to the deflection formula of the simply supported beam specimen 7 under the combined action of the uniformly distributed load and the concentrated load, the deflection of the simply supported beam specimen 7 at different positions under the combined action of the uniformly distributed load and the concentrated load is determined;

[0140] The stiffness distribution coefficient of the spring 62 along the distribution beam 61 is determined according to the relative displacement coefficients at different positions.

[0141] S201: Determine a method for calculating the deflection of the simply supported beam specimen 7 at different positions according to the deflection calculation formula (15) of the simply supported beam specimen 7 under the combined action of a uniformly distributed load and a concentrated load.

[0142] S202: Then, according to formula (16), the spring stiffness required at different positions of the simply supported beam specimen 7 under the combined action of uniformly distributed load and concentrated load is determined.

[0143] S203: According to the relative displacement coefficient δ of different positions i Determine the stiffness distribution coefficient of the spring along the distribution beam 61

[0144]

[0145] S204: From (17), we know

[0146]

[0147] S205: Finally, the stiffness distribution coefficient of the spring along the distribution beam 61 is determined according to formula (19), as shown in Table 4. It can be seen from formula (20) that the required spring stiffness distribution coefficient under the combined action of uniform load and concentrated load is exactly the same as the spring stiffness distribution coefficient required when the uniform load acts alone.

[0148] Table 4. Distribution coefficient of spring stiffness along the span of simply supported beam specimen

[0149]

[0150] When the simply supported beam specimens 7 with different spans are tested, the minimum spring stiffness is given by equation (18), and the spring stiffness coefficient is given by linear interpolation according to Table 4.

[0151] During the test, a servo hydraulic jack is used to control the load size, and the load state is monitored by the force sensor 4. The load provided by the servo hydraulic jack is evenly distributed to the tested beam specimen through the designed spring distribution beam 61, and then other servo hydraulic jacks are used to simulate the concentrated load to collaboratively complete the load form simulation of the uniformly distributed load and the concentrated load of the simply supported beam specimen 7.

[0152] Embodiment 2

[0153] Reference Figures 1-2As shown, an embodiment of a simply supported beam uniformly distributed load and concentrated load co-loading simulation device of the present invention, a simply supported beam uniformly distributed load and concentrated load co-loading simulation method described in any one of the above items uses the simulation device to complete the test, including:

[0154] The reaction floor 1 can be selected as a reaction floor 1 or a reaction groove according to laboratory conditions. If there is no reaction floor 1 or reaction groove in the laboratory, an I-beam or box-shaped steel beam can be used as a ground beam instead.

[0155] The support 2, on which the simply supported beam specimen 7 is placed. The support 2 is mounted on the reaction floor 1. Preferably, two supports 2 are provided, which are respectively arranged at the two ends of the simply supported beam specimen 7. The support 2 can use a concrete support 2 or a steel support 2 according to the conditions. During the simulation test, the position between the supports 2 is adjusted according to the span of the simply supported beam specimen 7 to be tested, and the support 2 is fixed to the reaction floor 1 by a bolt rod. Furthermore, the simply supported beam specimen 7 is connected to the two supports 2 in a different manner, using a fixed hinge support 2 and the other end connected by a rolling hinge support 2. For the reliability between the simply supported beam specimen 7 and the support 2, the simply supported beam specimen 7, the hinge support 2 and the support 2 can be fixed to the reaction floor 1 by a bolt rod.

[0156] The reaction frame 3 is arranged on the reaction floor 1, and the concentrated load servo hydraulic jack 51 is connected to the reaction frame 3, and a self-balancing system is formed between the reaction frame 3 and the reaction floor 1. The reaction frame 3 is composed of two I-beam columns and an I-beam beam, and the I-beam beam and the column are connected by bolts to form a gantry. The reaction frame 3 and the reaction floor 1 are connected by bolts to form a complete self-balancing system.

[0157] The uniform load servo hydraulic jack 52 is used to provide a load to the spring distribution beam 6, and is arranged above the spring distribution beam 6 to apply a downward load to the spring distribution beam 6. The uniform load servo hydraulic jack 52 is installed on the reaction frame 3 and applies a force downward. During the test, the uniform load servo hydraulic jack 52 is located directly above the simply supported beam specimen 7.

[0158] The concentrated load servo hydraulic jack 51 is used to provide a concentrated load to the simply supported beam specimen 7. It is arranged below the simply supported beam specimen 7 to apply an upward concentrated load to the simply supported beam specimen 7. According to the test requirements, one, two or three servo hydraulic jacks may be provided. The concentrated load servo hydraulic jack 51 is arranged on the reaction floor 1 and applies force to the simply supported beam specimen 7 above. During the test, the concentrated load servo hydraulic jack 51 is located directly below the simply supported beam specimen 7. The concentrated load servo hydraulic jack 51 is connected to the simply supported beam specimen 7 by a steel splint and a long rod bolt, and is connected to the reaction floor 1 by bolts. The number of servo hydraulic jacks is selected according to the form of concentrated load, and they are installed. When the test uses one concentrated load, one concentrated load servo hydraulic jack 51 is used. When the test uses two concentrated loads, two concentrated load servo hydraulic jacks 51 are used. When three concentrated loads are used in the test, three concentrated load servo hydraulic jacks 51 are used. The multiple concentrated load servo hydraulic jacks 51 may be equally spaced.

[0159] The uniform load servo hydraulic jack 52 cooperates with the spring distribution beam 6 to simulate the uniform load, and the concentrated load servo hydraulic jack 51 simulates the concentrated load. The uniform load servo hydraulic jack 52 and the concentrated load servo hydraulic jack 51 are controlled in coordination to simulate the combined effect of the uniform load and the concentrated load.

[0160] The spring distribution beam 6 is used to convert the load applied by the concentrated load servo hydraulic jack 51 into a uniformly distributed load, and apply the uniformly distributed load to the simply supported beam specimen 7. The spring distribution beam 6 includes a distribution beam 61 and a plurality of springs 62 arranged at equal intervals at the bottom of the distribution beam 61, and the springs 62 are in contact with one side of the simply supported beam specimen 7.

[0161] The distribution beam 61 is welded by I-beams or steel structural materials, and its bending rigidity should be much greater than that of the simply supported beam specimen 7 to prevent the distribution beam 61 from being deformed too much during the test.

[0162] The minimum stiffness of the spring 62 and the stiffness distribution coefficient of the spring 62 distributed along the distribution beam 61 are determined by the maximum theoretical deflection of the simply supported beam specimen 7 under the combined action of the uniformly distributed load and the concentrated load. The spring 62 is distributed along the distribution beam 61 with a stiffness that is larger in the middle and smaller at both ends. The spring 62 has different stiffnesses selected according to the design and is installed on one side of the distribution beam 61 at equal intervals with the designed stiffness distribution coefficient.

[0163] The minimum stiffness of the spring 62 is determined by the span, elastic modulus, and section inertia moment of the simply supported beam specimen 7 .

[0164] Among them, the minimum stiffness of the spring 62 is

[0165]

[0166] Where, E is the elastic modulus of the simply supported beam specimen 7, I is the section inertia moment of the simply supported beam specimen 7, δ max is the relative displacement coefficient of the maximum position along the span direction of the simply supported beam specimen, η is the load concentration coefficient, and ζ is the equivalent load coefficient;

[0167] The stiffness distribution coefficient of the spring 62 distributed along the distribution beam 61 is:

[0168]

[0169] In the formula, k i is the spring 62 stiffness required at different positions, δ i is the relative displacement coefficient at different positions along the span direction of the simply supported beam specimen 7, δ max is the relative displacement coefficient of the maximum position along the span direction of simply supported beam specimen 7;

[0170] The spring 62 is distributed along the distribution beam 61 with the spring stiffness being large in the middle and low at both ends, and the spring 62 is connected to the distribution beam 61 by welding. According to the distribution coefficient of the spring 62, different springs 62 are installed on the distribution beam 61 to form the spring distribution beam 6, and cooperate with the uniform load servo hydraulic jack 52 to realize the loading simulation of uniform load.

[0171] During the test, the spring 62 of the spring distribution beam 6 contacts the simply supported beam specimen 7, and the uniformly distributed load servo hydraulic jack 52 applies load to the distribution beam 61. The distribution beam 61 and the spring 62 convert the concentrated load into a uniformly distributed load and apply it to the simply supported beam specimen 7.

[0172] The force sensor 4 is used to monitor the force applied by the uniform load servo hydraulic jack 52 and the concentrated load servo hydraulic jack 51. The force sensor 4 is specifically a pressure sensor 4. One force sensor 4 is used for each uniform load servo hydraulic jack 52 and the concentrated load servo hydraulic jack 51. The force sensor 4 connected to the uniform load servo hydraulic jack 52 has one end connected to the reaction frame 3 by bolts, and the other end is connected to the uniform load servo hydraulic jack 52 by bolts and an adapter plate to detect the force applied by the uniform load servo hydraulic jack 52. The force sensor 4 connected to the concentrated load servo hydraulic jack 51 has one end connected to the simply supported beam specimen 7 by bolts, and the other end is connected to the concentrated load servo hydraulic jack 51 to detect the force applied by the concentrated load servo hydraulic jack 51.

[0173] Before the simulation test, the position of the support 2 on the reaction floor 1 is adjusted according to the span of the simply supported beam specimen 7 to be tested, and the support 2 is fixedly connected to the reaction floor 1. The simply supported beam specimen 7 to be tested is placed on the support 2, and the simply supported beam specimen 7 is connected to the support 2. The designed spring distribution beam 6 is placed on the simply supported beam specimen 7, and the spring 62 is in contact with the simply supported beam specimen 7. One of the force sensors 4 is connected to the reaction frame 3 by bolts, and one end of the uniformly distributed load servo hydraulic jack 52 is connected to the force sensor 4, and the other end is in contact with the distribution beam 61 of the spring distribution beam 6. One end of the concentrated load servo hydraulic jack 51 is connected to the bottom of the simply supported beam specimen 7, and the other end is connected to the reaction floor 1. The other force sensor 4 is arranged between the concentrated load servo hydraulic jack 51 and the simply supported beam specimen 7.

[0174] During the simulation test, the uniform load servo hydraulic jack 52 applies a concentrated load to the spring distribution beam 6 placed on the simply supported beam specimen 7. The spring distribution beam 6 designed by combining the distribution beam 61 and the spring 62 converts the load provided by the uniform load servo hydraulic jack 52 into a uniform load, and applies the uniform load to the simply supported beam specimen 7 to be tested. At the same time, the concentrated load servo hydraulic jack 51 applies a concentrated load to the simply supported beam specimen 7.

[0175] The size of the load is controlled by the uniform load servo hydraulic jack 52, the force state and the load size of the uniform load servo hydraulic jack 52 are monitored by the force sensor 4, the load provided by the uniform load servo hydraulic jack 52 is evenly distributed on the simply supported beam specimen 7 through the spring distribution beam 6, the size of the concentrated load is controlled by the concentrated load servo hydraulic jack 51, the force state and the load size of the concentrated load servo hydraulic jack 51 are monitored by the force sensor 4, and the simulation of the combined action of the uniform load and the concentrated load is completed.

[0176] The above technical solution of the present invention has the following advantages compared with the prior art:

[0177] The present invention discloses a method and device for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam. A device for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam specimen is designed by using a reaction frame, a reaction floor, a uniformly distributed load servo hydraulic jack, a concentrated load servo hydraulic jack, a force sensor, and a spring distribution beam. During the test, the load size is controlled by the uniformly distributed load servo hydraulic jack, and the load state is monitored by the force sensor. Finally, the load provided by the uniformly distributed load servo hydraulic jack is evenly distributed to the simply supported beam specimen under test through the designed spring distribution beam, and the concentrated force is simulated by using the concentrated load servo hydraulic jack, so as to collaboratively complete the load simulation of the combined loading of uniformly distributed load and concentrated load on the simply supported beam specimen.

[0178] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam, characterized in that: include: Before the simulation test, the maximum theoretical deflection of the simply supported beam specimen to be tested under the combined action of uniformly distributed load and concentrated load is obtained; According to the maximum theoretical deflection of the simply supported beam specimen, the minimum stiffness of the spring and the stiffness distribution coefficient of the springs distributed along the distribution beam are determined; According to the stiffness distribution coefficient of the spring along the distribution beam, a plurality of springs with different stiffnesses are arranged at the bottom of the distribution beam according to the stiffness distribution coefficient to form a spring distribution beam for testing the simply supported beam specimen; Among them, the minimum stiffness of the spring is Where, E is the elastic modulus of the simply supported beam specimen, I is the section moment of inertia of the simply supported beam specimen, δ max is the relative displacement coefficient of the maximum position along the span direction of the simply supported beam specimen, η is the load concentration coefficient, and ζ is the equivalent load coefficient; The stiffness distribution coefficient of the spring distributed along the distribution beam is In the formula, k i is the spring stiffness required at different positions, δ i is the relative displacement coefficient at different positions along the span direction of the simply supported beam specimen, δ max is the relative displacement coefficient at the maximum position along the span direction of the simply supported beam specimen; The step of determining the minimum stiffness of the spring comprises: According to the theoretical deflection coefficients under uniform load, single concentrated load and two concentrated loads, the deflection formula w of the simply supported beam specimen under the combined action of uniform load and concentrated load is obtained: i for Where q is the uniform load, l is the span of the simply supported beam specimen, and χ i The deflection distribution coefficient when uniformly distributed load and concentrated load are used together; According to the deflection formula of the simply supported beam specimen under the combined action of uniformly distributed load and concentrated load and Hooke's law, the stiffness k of the spring required at different positions of the simply supported beam specimen is obtained: i for and the minimum stiffness k of the spring min , where δ i is the relative displacement coefficient at different positions along the span direction of the beam, i is 0, 1 / 10, 2 / 10, 3 / 10, 4 / 10, 5 / 10, 6 / 10, 7 / 10, 8 / 10, 9 / 10, and 1.

2. A method for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 1, characterized in that: The step of obtaining the maximum theoretical deflection of the simply supported beam specimen under the combined action of a uniformly distributed load and a concentrated load comprises: According to the span of the simply supported beam specimen and the size of the uniformly distributed load, the bending moment distribution of the simply supported beam specimen under the uniformly distributed load is obtained; according to the span of the simply supported beam specimen and the size of a single concentrated load, the bending moment distribution of the simply supported beam specimen under the single concentrated load is obtained; according to the span of the simply supported beam specimen and the sizes of two concentrated loads, the bending moment distribution of the simply supported beam specimen under the two concentrated loads is obtained; The uniform load deflection curve formula is obtained according to the bending moment distribution under the uniform load; the single concentrated load deflection curve formula is obtained according to the bending moment distribution under the single concentrated load; the two concentrated load deflection curve formulas are obtained according to the bending moment distribution under the two concentrated loads; The parameters of the simply supported beam specimen at different positions are respectively introduced into the uniform load deflection curve formula, the single concentrated load deflection curve formula, and the two concentrated load deflection curve formula to obtain the theoretical deflection coefficients χ at different positions along the span direction of the simply supported beam specimen under the uniform load, the single concentrated load, and the two concentrated loads. i , see Table 1, Table 1. Deflection coefficient χ under different load forms i 3. The method for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 1, characterized in that: The step of determining the stiffness distribution coefficient of the springs distributed along the distribution beam comprises: According to the deflection w of the simply supported beam specimen under the combined action of uniformly distributed load and concentrated load i , determine the deflection of the simply supported beam specimen at different positions under the combined action of uniformly distributed load and concentrated load; According to the relative displacement coefficient δ at different positions i And the following formula Determine the stiffness distribution coefficient of the spring along the distribution beam, see Table 4, Table 4. Distribution coefficient of spring stiffness along the span of simply supported beam specimen When the simply supported beam specimens with different spans are tested, the spring stiffness coefficient is given by linear interpolation according to Table 4.

4. The method for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 3, characterized in that: The deflection coefficient under different load forms can be obtained by multiplying the deflection coefficient under uniform load by the unit load concentration coefficient, that is, Among them, under the action of uniformly distributed load, the load concentration coefficient η is 1; under the action of one concentrated load, the load concentration coefficient η is 1.57; under the action of two concentrated loads, the load concentration coefficient η is 1.35; under the action of three concentrated loads, the load concentration coefficient η is 1.

27.

5. The method for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 4, characterized in that: The equivalent load factor ζ is Where p is the total value of concentrated load.

6. The method for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 1, characterized in that: During the simulation test, the spring distribution beam is placed on the simply supported beam specimen, and the spring is in conflict with the simply supported beam specimen; a load is applied to the distribution beam of the spring distribution beam, and the spring distribution beam converts the load it receives into a uniformly distributed load, and applies a uniformly distributed load to one side of the simply supported beam specimen through the spring, and at the same time, a concentrated load is applied to the other side of the simply supported beam specimen.

7. A device for simulating the co-loading of uniformly distributed load and concentrated load on a simply supported beam, wherein the method for simulating the co-loading of uniformly distributed load and concentrated load on a simply supported beam as claimed in any one of claims 1 to 6 uses the device to complete the test, characterized in that: include: A support, on which the simply supported beam specimen is placed; A spring distribution beam comprises a distribution beam and a plurality of springs of different stiffness arranged at equal intervals at the bottom of the distribution beam, wherein the spring distribution beam is placed on the simply supported beam specimen, and the springs are in contact with the upper surface of the simply supported beam specimen; the minimum stiffness of the springs and the stiffness distribution coefficient of the springs distributed along the distribution beam are determined by the maximum theoretical deflection of the simply supported beam specimen under the combined action of a uniformly distributed load and a concentrated load; the springs are distributed along the distribution beam with a stiffness that is larger in the middle and smaller at both ends Among them, the minimum stiffness of the spring is Where, E is the elastic modulus of the simply supported beam specimen, I is the section moment of inertia of the simply supported beam specimen, δ max is the relative displacement coefficient of the maximum position along the span direction of the simply supported beam specimen, η is the load concentration coefficient, and ζ is the equivalent load coefficient; The stiffness distribution coefficient of the spring distributed along the distribution beam is In the formula, k i is the spring stiffness required at different positions, δ i is the relative displacement coefficient at different positions along the span direction of the beam, δ max is the relative displacement coefficient at the maximum position along the span direction of the beam; A uniformly distributed load servo hydraulic jack is arranged above the spring distribution beam, and applies a downward load to the spring distribution beam. The distribution beam and the spring convert the load into a uniformly distributed load and apply it to the simply supported beam specimen; A concentrated load servo hydraulic jack is arranged below the simply supported beam specimen and applies an upward concentrated load to the simply supported beam specimen; When determining the minimum stiffness of the spring, the deflection formula w of the simply supported beam specimen under the combined action of uniform load and concentrated load is obtained according to the theoretical deflection coefficients under uniform load, single concentrated load and two concentrated loads: i for Where q is the uniform load, l is the span of the simply supported beam specimen, and χ i The deflection distribution coefficient when uniformly distributed load and concentrated load are used together; According to the deflection formula of the simply supported beam specimen under the combined action of uniformly distributed load and concentrated load and Hooke's law, the stiffness k of the spring required at different positions of the simply supported beam specimen is obtained: i for and the minimum stiffness k of the spring min , where δ i is the relative displacement coefficient at different positions along the span direction of the beam, i is 0, 1 / 10, 2 / 10, 3 / 10, 4 / 10, 5 / 10, 6 / 10, 7 / 10, 8 / 10, 9 / 10, and 1.

8. The device for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 7, characterized in that: Also includes: A plurality of force sensors are provided for respectively monitoring the uniform load servo hydraulic jack and the force applied by the uniform load servo hydraulic jack; A reaction floor, the concentrated load servo hydraulic jack being connected to the reaction floor; A reaction frame is erected on the reaction floor, and a self-balancing system is formed between the reaction frame and the reaction floor; the uniformly distributed load servo hydraulic jack is connected to the reaction frame.

9. The device for simulating the combined loading of uniformly distributed load and concentrated load on a simply supported beam according to claim 7, characterized in that: The number of the concentrated load servo hydraulic jacks is one, two or three.

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