Analysis model of dry type joint floor and vibration analysis method

Abstract

To provide an analysis model of a dry type joint floor and a vibration analysis method capable of properly reproducing a behavior of an end side of a free floor panel not jointed to a beam, and acquiring a vibration analysis result with high reliability.SOLUTION: Provided is an analysis model 50 for a dry type joint floor which models, in a computer, a dry type joint floor in which a pair of end parts of a floor panel is mounted on two beams and the end parts of the floor panel and the beams are joined by joint hardware, and is applied when vibration analysis is executed. Beam models 10, 20 related to the beams are linear element models in which multiple first nodes 11, 21 on a straight line are connected by first wires 12, 22, a floor panel model 30 related to the floor panel is a plate element model in which multiple second nodes 31 being panel points of multiple straight lines along orthogonal two directions, are connected by a second wire 32, and each first node 11 of the linear element model 10 and each second node 31 of the corresponding plate element model 30 are connected in rigid body connection.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an analytical model and a vibration analysis method for a dry joint bed. [Background technology]

[0002] In recent years, with the diversification of building uses, there is a demand for large spaces using long-span beams in industrialized housing, and in order to realize this, it is necessary to properly evaluate the risk of vibration disorders caused by environmental vibrations (especially walking vibrations). In particular, buildings used as residences are spaces where residents can relax, and considering the extension of time spent at home against the backdrop of recent social conditions, even greater attention is needed to vibration disorders.

[0003] In industrialized housing, dry joints are sometimes used to join beams and floor panels to improve workability, but compared to wet joints, this dry joint has a lower degree of fixation between the beams and floor panels, and currently no method has been established to analytically evaluate floor vibration.For example, a method for evaluating floor vibration for a dry-jointed floor in which a pair of opposing ends (e.g., short sides) of a rectangular floor panel in plan view are placed on two beams, the ends of the beams and floor panel are joined with joint metal fittings, and the other pair of ends (e.g., long sides) are free and not fixed to the beams.

[0004] For example, Non-Patent Document 1 describes a study on a method for examining environmental vibrations in buildings, using an analytical model in which the four sides of a rectangular deck plate in plan view are fixed to the lattice-shaped steel beams that form the steel structural frame. In this analytical model, the four steel beams are modeled as line elements, and the deck plate is modeled as a flat element, and the four sides of the deck plate and the four steel beams are joined to each other by sharing corresponding nodes between them. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Study on Environmental Vibration Assessment Method for Buildings Part 2 Environmental Vibration Assessment Method Using Finite Element Analysis Models Abstracts of Academic Lectures at the Architectural Institute of Japan Annual Meeting (Hokkaido) August 2013 Summary of the Invention [Problem to be solved by the invention]

[0006] The analysis model described in Non-Patent Document 1 is an analysis model in which the four sides of the deck plate and the four steel beams are mutually joined, so it is possible to model them by sharing the corresponding nodes of both. However, if the model described in Non-Patent Document is applied to a dry-jointed floor in which only a pair of opposing ends of a rectangular floor panel in a plan view are joined to two beams as described above, the behavior of the other pair of free ends that are not joined to the beams cannot be reproduced due to the sharing of corresponding nodes between the beam and the floor panel. This also leads to the inability to reproduce the behavior of a dry-jointed floor in which the beam and the floor panel are not firmly fastened.

[0007] The present invention has been made in consideration of the above-mentioned problems, and relates to an analytical model for a dry-jointed floor in which a pair of opposing ends of a floor panel are placed on two beams and the ends of the beams and floor panel are joined with joining metal fittings, and a vibration analysis method using this analytical model.The present invention aims to provide an analytical model and vibration analysis method for a dry-jointed floor that can appropriately reproduce the behavior of the free end edges of floor panels that are not joined to beams and can obtain highly reliable vibration analysis results. [Means for solving the problem]

[0008] In order to achieve the above object, one embodiment of the analytical model of the dry joint bed according to the present invention is as follows: A dry-jointed floor is a floor panel with a pair of opposing ends placed on two beams, and the ends of the beams and the floor panel are joined by metal joints. This is an analytical model of the dry-jointed floor, which is modeled in a computer and applied when performing vibration analysis. The beam model for the beam is a line element model in which a plurality of first nodes on a straight line are connected by a first wire, The floor panel model for the floor panel is a plate element model in which a plurality of second nodes, which are grid points of a plurality of straight lines along two orthogonal directions, are connected by second wires, The method is characterized in that each first node of the line element model and each corresponding second node of the plate element model are rigidly connected.

[0009] According to this aspect, multiple first nodes on the straight lines that make up the beam model, which is a line element model, and multiple second nodes that are grid points of multiple straight lines along two orthogonal directions that make up the floor panel model, which is a plate element model, are rigidly connected, and as a result, the nodes of the beam model and the nodes of the floor panel model are separated, and it is possible to separate the behavior of the edge of the floor panel model that is not dry-jointed to the beam model from the behavior of the beam model, and it becomes possible to appropriately reproduce the behavior of the edge of the free floor panel that is not joined to the beam. This makes it possible to obtain highly reliable vibration analysis results.

[0010] Here, the floor panels that are the subject of the floor panel model can be deck plates, plywood (including structural plywood), cross laminated timber (CLT), laminated veneer lumber (LVL), autoclaved light weight concrete (ALC), etc. Also, the beams that are the subject of the beam model can be steel beams formed from shaped steel materials such as H-shaped steel.

[0011] In another embodiment of the analytical model of the dry joint bed according to the present invention, The plate element model is a rectangle in a plan view and has a pair of short sides and a pair of long sides, One of the pair of short sides and the pair of long sides is rigidly connected to the line element model, and the other is free.

[0012] According to this aspect, regardless of whether the long side or short side of a rectangular floor panel model in a plan view is free, the behavior of the free long side or short side can be appropriately reproduced.

[0013] Another aspect of the analytical model of the dry joint bed according to the present invention is as follows: The rigid body connection length is set based on the relationship between the natural frequency of the analysis model and the rigid body connection length when the rigid body connection length is changed.

[0014] According to this aspect, the rigid connection length is set based on the relationship between the natural frequency of the analysis model and the rigid connection length when the rigid connection length is changed, so that an analysis model that appropriately reflects the actual dry joint bed can be formed. For example, when performing a vibration experiment on an actual dry joint bed, the natural frequency obtained in the vibration experiment can be applied to a relationship graph between the natural frequency and the rigid connection length to specify an appropriate rigid connection length, which can be reflected in the analysis model.

[0015] Another aspect of the analytical model of the dry joint bed according to the present invention is as follows: The rigid connection length reflects the degree of fixation between the beam and the floor panel.

[0016] According to this aspect, the degree of fixation between the beam and the floor panel can be reflected by adjusting the rigid connection length, and the degree of fixation according to the fixing form of the end of the beam and the floor panel can be appropriately modeled. For example, the inventors have determined that the relatively loose degree of fixation when the end of the floor panel is placed on the beam via vibration-proof rubber or the like and joined with a joint metal (joint metal) can be adjusted by the rigid connection length.

[0017] In other words, in addition to separating the behavior of the beam from the behavior of the free end of the floor panel, the rigid connection makes it possible to appropriately evaluate the degree of fixation between the ends of the beam and floor panel based on its length, and furthermore, as described above, makes it possible to adapt the natural frequency of the analytical model to the natural frequency of an actual dry-jointed floor.

[0018] In addition, one aspect of the vibration analysis method for a dry-type joint bed according to the present invention is as follows: An analytical model creation process of creating an analytical model of the dry joint bed in a computer; and an analysis execution step of executing a vibration analysis to input a vibration force to a predetermined position of the analysis model and calculate vibration at the predetermined position of the analysis model.

[0019] According to this aspect, by inputting an excitation force at a predetermined position of the analytical model of the present invention and performing vibration analysis to calculate the vibration at a predetermined position of the analytical model, it is possible to appropriately reproduce the behavior of the edge of the free floor panel that is not joined to the beam, and to obtain highly reliable vibration analysis results for dry-jointed floors.

[0020] Another aspect of the vibration analysis method for a dry-bonded bed according to the present invention is as follows: a rigid body connection length setting step of: performing an eigenvalue analysis on the analysis model to identify a natural frequency; specifying a natural frequency of the analysis model when a rigid body connection length, which is the length of the rigid body connection, is changed; creating a relationship graph between the natural frequency and the rigid body connection length; and setting the rigid body connection length within a range of the rigid body connection length corresponding to a range of ±0.5 Hz of the natural frequency of the analysis model; The analytical model creating step is characterized in that the set rigid body connection length is applied to the analytical model.

[0021] According to this embodiment, by setting the rigid connection length within the range of the rigid connection length when the range of the natural frequency obtained by eigenvalue analysis of the analytical model of an actual dry-bonded bed, ±0.5 Hz, is applied to a relationship graph between the natural frequency and the rigid connection length, an analytical model that appropriately models the actual dry-bonded bed can be created, and highly reliable vibration analysis results for the dry-bonded bed can be obtained. Effect of the Invention

[0022] As can be understood from the above explanation, according to the analytical model and vibration analysis method of the dry-jointed floor of the present invention, an analytical model for a dry-jointed floor in which a pair of opposing ends of a floor panel are placed on two beams and the ends of the beams and floor panel are joined with joining metal fittings, and a vibration analysis method using this analytical model, it is possible to appropriately reproduce the behavior of the free end edge of the floor panel that is not joined to the beams, and to obtain highly reliable vibration analysis results. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a plan view of an example of a simulated floor installed on steel beams. [Figure 2A] This is an exploded perspective view of a steel beam and an ALC panel. [Figure 2B] This is a diagram showing an ALC panel dry-joined to a steel beam using metal joints. [Figure 2C] This is a perspective view showing the state in which an ALC panel is installed on a steel beam. [Diagram 3] FIG. 2 is a plan view showing a simulated floor analysis model. [Figure 4] FIG. 1 is a perspective view of an example of an analytical model of a dry joint bed according to an embodiment. [Diagram 5] FIG. 13 is a perspective view of an example of an analytical model of a dry joint bed according to a reference embodiment. [Figure 6] FIG. 1 is a diagram showing an example of a time-series waveform of a walking excitation force used in vibration analysis. [Figure 7] FIG. 13 is a diagram showing an example of a graph showing the relationship between rigid body connection length and natural frequency. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an example of an analytical model and a vibration analysis method for a dry joint bed according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanation.

[0025] [Analysis model of dry joint floor and vibration analysis method according to the embodiment] An example of an analytical model of a dry-jointed floor and a vibration analysis method according to the embodiment will be described with reference to Figs. 1 to 7. Here, Fig. 1 is a plan view of an example of a simulated floor installed on a steel beam. Also, Fig. 2A is an exploded perspective view of a steel beam and an ALC panel, Fig. 2B is a view showing a state in which the ALC panel is dry-joined to the steel beam with a joint metal, and Fig. 2C is a perspective view showing a state in which the ALC panel is installed on the steel beam. Furthermore, Fig. 3 is a plan view showing a simulated floor analytical model, and Fig. 4 is a perspective view of an example of an analytical model of a dry-jointed floor according to the embodiment.

[0026] The simulated floor shown in Figure 1 is composed of H-shaped steel beams (steel beams), vibration-proof rubber, ALC panels, and particle board, and is 5.46 m long and 3.64 m wide.

[0027] The ALC panel has a short side of 0.606 m and a long side of 1.81 m. As shown in Figure 2A, only the short sides come into contact with the vibration-proof rubber and beams. The ALC panel is fixed to the beams with connecting metal fittings, shown enlarged in Figure 2B, to form a dry-jointed floor.

[0028] The particle board is fastened to the ALC panel with screws at intervals of 303 mm or less. The mock floor has six support points, and is configured to transmit the load to the floor of the test site via joint members between the beams (Joint Box (registered trademark)) or support point jigs.

[0029] The simulated floor analysis model applied to the vibration analysis (FEM analysis: Finite Element Method) of the simulated floor shown in Fig. 1 is as shown in Fig. 3, and an analysis model 50 is formed by dry-joining only a pair of short sides of a plurality of beams along the long side direction and a plurality of ALC panels placed on the plurality of beams along the short side direction to a pair of beams as shown in Figs. 2A to 2C. Fig. 3 illustrates a plurality of analysis models 50 in the right column, illustrates the plurality of analysis models 50 up to the middle in the center column, and omits the analysis models 50 in the left column, illustrating the horizontal brace, which is a line element model, below them.

[0030] The physical property parameters of the line element model and plate element model that make up the analytical model are shown in Tables 1 and 2 below.

[0031] [Table 1]

[0032] [Table 2]

[0033] FIG. 4 is an enlarged view of the analytical model 50 shown in FIG.

[0034] The damping constant is set to 0.6% for all modes, and the mesh pitch of the beam (line element model) and floor (plate element model) is 151.67mm. The distance t (hereafter referred to as the rigid connection length) between the node of the beam (line element model) and the node of the floor (plate element model) is set to 119.7mm, for example. The support conditions, beam end connection conditions, and boundary conditions for the ALC panels are shown in Table 3 below.

[0035] [Table 3]

[0036] The boundary conditions of the ALC panel set whether or not to transmit stress at each degree of freedom to adjacent plate elements. Since the short side of the simulated floor is always fixed to the beam, the condition is set to transmit stress to all degrees of freedom, while the long side transmits stress only through the particle board, so the condition is set to not transmit stress in the out-of-plane rotation direction.

[0037] As shown in FIG. 4, the analysis model 50 has beam models 10 and 20, which are a pair of line element models along the short side direction and long side direction, respectively, and a floor panel model 30, which is a plate element model.

[0038] The beam model 10 along the short side direction is a line element model in which a plurality of first nodes 11 on a straight line are connected by a first wire 12, and the beam model 20 along the long side direction is a line element model in which a plurality of first nodes 21 on a straight line are connected by a first wire 22.

[0039] On the other hand, the floor panel model 30 is a plate element model in which a plurality of second nodes 31, which are grid points of a plurality of straight lines along two orthogonal directions (short side direction and long side direction), are connected by second wires 32.

[0040] Each first node 11 of the line element model 10 along the short side direction and each second node 31 of the corresponding plate element model 30 are joined by a rigid connection 40 having a rigid connection length t.

[0041] As shown in the illustrated example, a number of first nodes 11 on the straight lines that constitute the beam model 10, which is a line element model, and a number of second nodes 31 that are the grid points of a number of straight lines along two orthogonal directions that constitute the floor panel model 30, which is a plate element model, are joined by rigid connections 40, thereby making it possible to separate the nodes of the beam model 10 and the nodes of the floor panel model 30.

[0042] As a result, the end edge 35 of the floor panel model 30 and the end edge 25 of the beam model 20, which are not originally dry-jointed to each other, are separated, and the behavior of the end edge 35 of the floor panel model 30 and the behavior of the end edge 25 of the beam model 20 are separated, making it possible to appropriately reproduce the behavior of the free end edge 35 of the floor panel model 30 that is not joined to the beam model 20. This leads to highly reliable vibration analysis results.

[0043] For example, Fig. 5 is a perspective view of an example of an analytical model of a dry joint bed according to a reference embodiment. In a pair of beam models 60, each node 61 is connected by a wire 62, and in another pair of beam models 70, each node 71 is connected by a wire 72.

[0044] When an analysis model 90 is created by sharing the corresponding nodes 81 of a floor panel model 80, in which multiple nodes 81, which are lattice points of multiple straight lines along two orthogonal directions, are connected to each node 61, 71 of each pair of beam models 60, 70 by wires 82, the end edge along the long side direction of the floor panel model 80, which should be essentially free, is constrained by the beam model 70, and as a result, it is not possible to properly reproduce the behavior of the end edge of the floor panel model 80. This can lead to unreliable vibration analysis results.

[0045] Returning to FIG. 3, in the vibration analysis method according to the embodiment, a simulated floor analytical model 60 including a plurality of analytical models 50 is created in a computer (analysis model creating step).

[0046] In Fig. 3, acc1 to acc4 indicate the locations where accelerometers were installed on the simulated floor that was actually created. That is, in order to verify the accuracy of the analysis results, the inventors performed a walking vibration experiment on the simulated floor that was actually created, and performed vibration measurements using four accelerometers.

[0047] Following the analytical model creation process, a walking excitation force as shown in FIG. 6 is input at a walking rate of 2 Hz to the walking excitation force input positions (footprint positions at 455 mm pitch in FIG. 3) of the simulated floor analytical model 60, and a vibration analysis is performed to calculate the vibration at the specified positions of the analytical models 50 and 60.

[0048] Here, the analysis software to be applied may be, for example, midas iGen (manufactured by Midas IT Japan Co., Ltd.), which is one of the general-purpose structural analysis software. The walking excitation force shown in Fig. 6 is a walking force of a pedestrian measured separately in a walking vibration experiment (analysis execution step).

[0049] The inventors performed an eigenvalue analysis on the analytical model and obtained the natural frequency of the analytical model shown in the figure as 13.54 Hz. Meanwhile, in a separate walking vibration experiment, the natural frequency of the simulated floor was obtained as 13.07 Hz, and the difference between the experimental value (measured value) and the analytical value for the natural frequency was only 0.47 Hz, so that the two values ​​roughly matched each other.

[0050] FIG. 7 shows the change in the natural frequency when the rigid body connection length, which is the length of the rigid body connection, is changed.

[0051] Figure 7 shows that the natural frequency tends to increase as the rigid connection length increases. This is believed to be because the degree of fixation of the plate element ends increases in proportion to the rigid connection length.

[0052] In the simulated floor, the distance from the beam core to the ALC panel core is approximately 180 mm, but according to Fig. 7, when the rigid connection length is set to 180 mm, the natural frequency deviates from the experimental results. This is thought to be because the fixing of the ALC panel end is not a completely rigid connection.

[0053] Therefore, in this analysis model, the degree of fixation of the ALC panel ends (the effects of the connecting metal fittings and vibration-damping rubber) can be reproduced by adjusting the rigid connection length, and it is believed that this allows a natural frequency close to the measured value to be obtained.

[0054] The vibration analysis results are shown in Table 4 below.

[0055] [Table 4]

[0056] VLT is used as an index of the results of this vibration analysis. VLT is a vibration evaluation index that quantifies human evaluation by applying a sensory testing method, and more specifically, it is a value calculated using a formula derived from an acceleration-time curve based on the relationship between human evaluation and the walking vibration input by the inspector during the inspection. The formula for VLT can be expressed as the following formula (X).

[0057]

number

[0058] From Table 4, the difference between the VLT analysis results and the experimental results (average of three runs) is at most 0.6 dB. This proves that the analytical model can generally reproduce the experimental results.

[0059] In addition, the present invention is not limited to the configuration shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like of the above-mentioned embodiment. In this regard, the present invention may be modified within the scope of the gist of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0060] 10: Beam model (line element model) 11: First node 12:First wire rod 20: Beam model (line element model) 21: First node 22: 1st wire rod 25: Edge 30: Floor panel model (plate element model) 31: 2nd node 32:Second wire rod 35: Edge 40: Rigid body connection 50:Analysis model (analysis model of dry joint floor, analysis model) 60: Simulation floor analysis model (analysis model)

Claims

1. A dry-jointed floor is a floor panel having a pair of opposing ends placed on two beams, and the ends of the beams and the floor panel are joined by metal joints. The dry-jointed floor is modeled in a computer and is applied when performing vibration analysis. the beam model for the beam is a line element model in which a plurality of first nodes on a straight line are connected by a first wire; The floor panel model for the floor panel is a plate element model in which a plurality of second nodes, which are grid points of a plurality of straight lines along two orthogonal directions, are connected by second wires, An analytical model of a dry-jointed bed, characterized in that each first node of the line element model and each corresponding second node of the plate element model are rigidly connected.

2. The plate element model is a rectangle in a plan view and has a pair of short sides and a pair of long sides, The analytical model of a dry joint bed as described in claim 1, characterized in that one of the pair of short sides and the pair of long sides is rigidly connected to the line element model, and the other is free.

3. The analytical model of a dry joint bed described in claim 1, characterized in that the rigid connection length, which is the length of the rigid connection, is set based on the relationship between the natural frequency of the analytical model and the rigid connection length when the rigid connection length is changed.

4. The analytical model of a dry-jointed floor according to claim 3, characterized in that the rigid connection length reflects the degree of fixation between the beam and the floor panel.

5. An analytical model creation process for creating an analytical model of the dry joint bed according to any one of claims 1 to 4 in a computer; A vibration analysis method for a dry joint bed, comprising: an analysis execution step of inputting a vibration force to a predetermined position of the analysis model and executing a vibration analysis to calculate the vibration at the predetermined position of the analysis model.

6. a rigid body connection length setting step of: performing an eigenvalue analysis on the analysis model to identify a natural frequency; specifying a natural frequency of the analysis model when a rigid body connection length, which is the length of the rigid body connection, is changed; creating a relationship graph between the natural frequency and the rigid body connection length; and setting the rigid body connection length within a range of the rigid body connection length corresponding to a range of ±0.5 Hz of the natural frequency of the analysis model; The vibration analysis method for a dry joint bed according to claim 5, characterized in that in the analysis model creation step, the set rigid body connection length is applied to the analysis model.

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