Device and method for detecting internal force transmission path of structure

Abstract

A structure internal force transmission path detection device and method belong to the technical field of measurement and comprise a body structure system and a measurement system. The body structure system comprises a shell and a force measuring unit; the measuring system comprises a pressure measuring strain gauge, a foil type strain gauge, a spring, a signal transmission line and a computer. The interior of the to-be-measured structure is divided into a plurality of force measuring units, then loads borne in the units are calculated, and a main force transmission path in the structure is found out step by step, so that the action form of the internal force of the structure can be concrete and is more convenient to understand, an engineer is guided to optimize the structural design, and the overall performance is improved. The invention provides an experimental device and method for quantification and explicit expression of a transmission route of internal force of a complex structure.

Description

Technical Field

[0001] The present invention belongs to the field of measurement technology, and in particular relates to a device and method for detecting a force transmission path inside a structure. Background Art

[0002] The quantification and explicit expression of the main force transmission path inside the structure can provide guidance for structural design and optimization, facilitate mechanical performance testing and evaluation, and help engineers optimize the structural layout, make the internal force distribution more uniform, improve the structural stiffness, and achieve the goal of lightweight design. In existing technologies, the explicit expression of the force transmission path is usually achieved through finite element analysis combined with simulation, but lacks experimental verification. In terms of experiments, some researchers have used strain gauges to measure the force transmission path on the outer surface of the structure, but there is no reasonable solution for how to measure the internal structure. This will make it difficult for engineers to determine the law of force transmission inside the structure, and it is impossible to adjust the structural layout and component size in a targeted manner, resulting in unreasonable design solutions.

[0003] Therefore, it is necessary to explore a device and method for detecting the load transfer law inside the structure, so as to provide an experimental basis for the quantification and explicit expression of the load transfer law in various regions inside the mechanical structure. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for detecting the internal force transmission of a structure, wherein the interior of the structure to be measured is divided into a number of square force measuring units of regular shapes and wrapped with a shell, connecting springs and strain gauges are added between the force measuring units, and when a load is applied to the structure to be measured, the high-sensitivity springs and strain gauges on the cube force measuring units can measure the corresponding tension and pressure between the units, and the magnitude and direction of each force are obtained by numerical calculation, and the forces are selected and discarded to obtain the main force transmission path of the structure.

[0005] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0006] The present invention provides a device for detecting the force transmission path inside a structure, comprising a main body structure system and a measuring system. The main body structure system comprises a housing and a force measuring unit; the measuring system comprises a pressure measuring strain gauge, a foil strain gauge, a spring, a signal transmission line, and a computer.

[0007] Furthermore, the main structure system is composed of an outer shell and a number of cubic force measuring units. According to the geometric characteristics of the structure to be measured, its structural shell is established, and the geometric structure inside the shell is divided into discrete units, namely the force measuring units. Blind holes are opened on the inner surface of the shell and the surface of the force measuring units. Each force measuring unit has six blind holes. The number of blind holes on the outer shell corresponds to the number of blind holes of the force measuring units it contacts. A spring is placed along the axial position between the blind holes formed in pairs, and the depth of each blind hole is half the length of the spring.

[0008] Furthermore, the piezoresistive strain gauges of the measurement system are pasted at the diagonal positions on six surfaces of the force measuring unit with glue to detect the pressure received by each surface of the force measuring unit; cyanoacrylate adhesives are applied on each blind hole of the outer shell and inside each blind hole of the force measuring unit. One end of the spring is bonded to the blind hole on the outer shell, and the other end is bonded to the blind hole on the force measuring unit. For two mutually contacting force measuring units, both ends of the spring are bonded to the blind holes on the force measuring unit; the foil strain gauge is pasted on the outer surface of the spring through glue to detect the tensile force received by the force measuring unit; all measured pressure values and tensile force values are transmitted to the computer through signal transmission lines.

[0009] Furthermore, according to the loads and constraints of the structure, six-degree-of-freedom constraints are added to the constrained positions of the outer shell, and loads are applied to the force-bearing positions. The several force measuring units filled in the outer shell will generate mutual forces under the action of the force. The force-bearing conditions on the six force-bearing surfaces of the force measuring unit are different, but all are from the x and y directions. Denote the force on the first surface of the i-th force measuring unit among n force measuring units as (F i , F ix1 ), the force on the second surface as (F iy1 , F ix2 )......, and the force on the sixth surface as (F iy2 , F ix6 ); then, the forces belonging to the x direction or y direction are added respectively through the composition of forces to obtain the force received by the force measuring unit as (F iy6 , F ix ), and further calculate the final force as F iy . Calculate the forces F1, F2,... F i ,... F i ,... F n of n force measuring units in this way. Compare the magnitudes of the resultant forces of these force measuring units, discard the smaller forces, and leave the larger forces. Connect the remaining forces in the direction of the resultant force to form a line, which forms a transmission channel, that is, the main force transmission path of the structure.

[0010] The beneficial effects of the present invention are:

[0011] 1. The force measuring unit can measure the load magnitude at the center position of all force measuring units inside the structure to be measured, thereby visualizing the force transmission path inside the structure, effectively overcoming the defects of the current method of using stress to express the local force-bearing state of the structure, and providing an experimental method for the quantification and explicit expression of the load transmission law in each region inside the mechanical structure.

[0012] 2. By dividing the interior of the structure to be measured into several force-measuring units, accurately calculating the internal forces within the unit volume, and gradually finding the force transmission path, the force transmission path of complex structures can be effectively and explicitly expressed, providing scientific guidance for the design of load-bearing structures and material distribution.

[0013] 3. The internal force transmission path detection device proposed by the present invention visualizes the form of internal force action in the structure, which is easy to understand. The measurement method is fast, efficient, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The front view of an internal force transmission path detection device of the present invention.

[0015] Figure 2 The schematic diagram of the structure to be measured and the force conditions of the present invention.

[0016] Figure 3 The schematic diagram of the connection between force-measuring units of the present invention.

[0017] Figure 4 The schematic diagram of the connection between the outer shell and the force-measuring unit of the present invention.

[0018] Figure 5 The schematic diagram of the measurement results of the internal load of the structure to be measured of the present invention.

[0019] Figure 6 The schematic diagram of the internal force transmission path results of the structure to be measured of the present invention.

[0020] DESCRIPTION OF THE REFERENCE NUMERALS:

[0021] 100 is the main body structure system, 200 is the measurement system, 101 is the outer shell, 102 is the force-measuring unit, 201 is the piezoresistive strain gauge, 202 is the foil strain gauge, 203 is the spring, 204 is the signal transmission line, and 205 is the computer. DETAILED DESCRIPTION OF THE INVENTION

[0022] For a better explanation of the present invention and for ease of understanding, the following is a detailed description of the present invention in conjunction with the attached Figures 1 to 6 drawings through specific embodiments.

[0023] The present invention provides an internal force transmission path detection device for a structure, including a main body structure system 100 and a measurement system 200. The main body structure system includes an outer shell 101 and a force-measuring unit 102; the measurement system 200 includes a piezoresistive strain gauge 201, a foil strain gauge 202, a spring 203, a signal transmission line 204, and a computer 205.

[0024] Further, the body structure system 100 is composed of a housing 101 and several cube-shaped force measuring units 102. Taking a simply supported beam as an example, according to the geometric characteristics of the structure to be measured, its structural housing 101 is established, and the internal geometric structure of the housing 101 is divided into discrete units, which are the force measuring units 102. Blind holes are provided on the inner surface of the housing 101 and the surface of the force measuring unit 102. Denote the blind hole on the inner surface of the housing as blind hole A and the blind hole on the surface of the force measuring unit as blind hole B. Each force measuring unit 102 has six blind holes, and the number of blind holes on the housing corresponds one-to-one with the number of blind holes of the force measuring unit 102 in contact with it. A spring 203 is placed along the axial direction between the two paired blind holes, and the depth of each blind hole is half of the length of the spring 203.

[0025] Further, the piezoresistive strain gauges 201 of the measurement system 200 are pasted at the diagonal positions on the six surfaces of the force measuring unit 102 with glue to detect the pressure received by each surface of the force measuring unit 102; cyanoacrylate adhesive is applied to each blind hole on the housing 101 and inside each blind hole of the force measuring unit 102. One end of the spring 203 is bonded to the blind hole on the housing 101, and the other end is bonded to the blind hole on the force measuring unit 102. For two mutually contacting force measuring units 102, both ends of the spring 203 are bonded to the blind holes on the force measuring unit 102; the foil strain gauge 202 is pasted on the outer surface of the spring 203 with glue to detect the tensile force received by the force measuring unit 102; all the measured pressure values and tensile force values are transmitted to the computer 205 through the signal transmission line 204, as Figure 3 , Figure 4 shown.

[0026] Further, taking a simply supported beam as an example for the method for detecting the internal force transmission path of a structure, the two ends of the bottom of the housing 101 are fixed, and a load F is applied at the middle position of the top to cause the body structure system 100 to deform; the several force measuring units 102 filled in the housing 101 will generate mutual forces under the action of the force. The force conditions on the six force-bearing surfaces of the force measuring unit 102 are different, but all are from the x and y directions. Denote the force on the first surface of the i-th force measuring unit n i among the n force measuring units 102 as (F ix1 , F iy1 ), the force on the second surface as (F ix2 , F iy2 )......, and the force on the sixth surface as (F ix6 , F iy6 ); then, by the composition of forces, the forces belonging to the x direction or y direction are added respectively to obtain the force received by the force measuring unit 102 as (F ix , F iy ), and further calculate the final force as F i . Calculate the forces F1, F2,... F of the n force measuring units 102 according to this methodi ,...F n , compare the magnitudes of the resultant forces of these force measuring units 102, discard the smaller forces, retain the larger forces, and connect the retained forces in the direction of the resultant force to form a line, thereby forming a transmission path, which is the main force transmission path of the structure, as Figure 6 shown.

[0027] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A device and method for detecting a force transmission path inside a structure, characterized in that: It includes a main body structure system and a measuring system. The main body structure system includes a housing and a force measuring unit; the measuring system includes a pressure measuring strain gauge, a foil strain gauge, a spring, a signal transmission line, and a computer.

2. A device and method for detecting a force transmission path inside a structure according to claim 1, characterized in that: The main structure system consists of an outer shell and a number of cubic force measuring units. According to the geometric characteristics of the structure to be measured, its structural shell is established, and the geometric structure inside the shell is divided into discrete units, namely the force measuring units. Blind holes are opened on the inner surface of the shell and the surface of the force measuring units. Each force measuring unit has six blind holes. The number of blind holes on the shell corresponds to the number of blind holes of the force measuring units it contacts. A spring is placed along the axial position between the blind holes formed in pairs, and the depth of each blind hole is half the length of the spring.

3. A device and method for detecting a force transmission path inside a structure according to claim 1, characterized in that: The pressure strain gauges of the measuring system are glued to the diagonal positions of the six surfaces of the force measuring unit to detect the pressure on each surface of the force measuring unit; cyanoacrylate adhesive is coated on each blind hole of the shell and each blind hole of the force measuring unit, one end of the spring is glued to the blind hole on the shell, and the other end is glued to the blind hole on the force measuring unit. For two force measuring units in contact with each other, both ends of the spring are glued to the blind holes on the force measuring unit; the foil strain gauge is glued to the outer ring surface of the spring to detect the tension on the force measuring unit; all measured pressure values ​​and tension values ​​are transmitted to the computer through the signal transmission line.

4. A device and method for detecting a force transmission path inside a structure according to claim 1, characterized in that: According to the load and constraint of the structure, six degrees of freedom constraints are added to the constrained position of the shell, and loads are applied to the force-bearing position. The force-measuring units filled in the shell will generate interaction forces under the action of the force. The force conditions on the six force-bearing surfaces of the force-measuring units are different, but they are all affected from the x and y directions. The i-th force-measuring unit n among the n force-measuring units is recorded as i The force on the first surface is (F ix1 ,F iy1 ), the force on the second surface is (F ix2 , F iy2 )......, the force on the sixth surface is (F ix6 , F iy6 ); then, by combining the forces in the x-direction or y-direction, the force on the force measuring unit is obtained as (F ix , F iy ), and then calculate the final force as F i According to this method, the forces F1, F2, ... F of n force measuring units are obtained. i ,...F n , compare the size of the resultant force of these force measuring units, discard the small force, keep the larger force, and connect the remaining forces into a line according to the direction of the resultant force to form a transmission channel, which is the main force transmission path of the structure.

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