Device and method for predicting elastic modulus of wood composite laminate

Abstract

The invention discloses a device and method for predicting the elastic modulus of a wood composite laminate, and the method comprises the steps: fixing a piezoelectric wafer on the surface of a composite laminate unit, enabling the piezoelectric wafer to be in a free state, enabling the piezoelectric wafer to generate a sinusoidal vibration signal through a piezoelectric driving device, collecting the sinusoidal vibration signal through an acceleration sensor, and transmitting the signal to an upper computer; first three-order inherent frequencies are obtained through fast Fourier transform, a first-order dynamic elastic modulus is calculated to serve as an input parameter of a finite element model, then a geometric model is established through COMSOL, related parameters are input, boundary conditions and loads are set, the model is operated after superfine grids are divided, and a third principal stress and a third principal strain are subjected to volume integration, so that a finite element model is obtained. According to the method, the performance of each composite laminate is detected in a nondestructive mode, physical damage and resource waste are avoided, finite element analysis and finite times of experiments are combined, the detection time and cost are remarkably reduced, and the overall efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical property detection, in particular to a device and method for predicting the elastic modulus of a wood composite laminate. Background Art

[0002] Wood composite panels, consisting of multiple layers of wood veneer or wood veneer bonded with wood-based panels using adhesives, are widely used in construction, home improvement, furniture, packaging, and sports equipment due to their lightweight, high strength, wear resistance, moisture resistance, fire resistance, sound insulation, and thermal insulation properties. With the growing global adoption of sustainable development, wood composite panels are becoming an important choice in modern architectural design due to their recyclability, low carbon footprint, and environmental friendliness. Among engineering materials, the flexural modulus is a key parameter that measures material stiffness and mechanical properties, directly influencing deformation, stress distribution, and stability. For wood composite panels, accurate prediction of the elastic modulus is not only fundamental to ensuring structural safety but also provides a theoretical basis for optimizing material design and improving performance. However, the mechanical properties of composite panels are influenced by factors such as the nature of the individual layers, the number of layers, thickness, orientation, and arrangement order, making the prediction of the elastic modulus challenging.

[0003] Currently, the measurement of the elastic modulus of laminates relies primarily on two methods: static and dynamic nondestructive testing. The static method measures stress and strain by applying a constant load. Although accurate, it has disadvantages such as long testing time, strong destructiveness, and the need for a large number of specimens. The dynamic nondestructive testing method calculates the elastic modulus by measuring the dynamic response of the material. Although it has the advantages of simple equipment and rapid testing, it also faces problems such as large environmental interference, complex data processing, and poor result stability. In addition, traditional theoretical and experimental methods have limitations when predicting the elastic modulus of laminates: theoretical methods require excessive simplifying assumptions about material properties, which may lead to prediction errors; while experimental methods can reflect actual performance, they are time-consuming and material-intensive, and cannot meet the requirements of modern architectural engineering design for efficiency and accuracy. As a powerful engineering tool, finite element analysis (FEA) can simulate the mechanical behavior of materials under different loading conditions, providing an efficient and accurate means for predicting the elastic modulus of laminates. Summary of the Invention

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid blurring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0005] Therefore, an object of the present invention is to provide a device and method for predicting the elastic modulus of a wood composite laminate, so as to solve the problems raised in the above background technology.

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions: A device for predicting the elastic modulus of a wood composite laminate, comprising: A vibration excitation element is fixed on the wood composite board to be tested; a piezoelectric drive device connected to the vibration excitation element, for applying a periodic mechanical force to the vibration excitation element to generate a sinusoidal vibration signal; A signal acquisition device is installed on the wood composite board to be tested and receives the vibration signal of the composite board unit to be tested; The data processing component obtains the vibration signal transmitted by the signal acquisition device and performs data processing, analysis and prediction.

[0007] As a preferred solution of the device for predicting the elastic modulus of a wood composite laminate according to the present invention, the vibration excitation element is a piezoelectric chip.

[0008] As a preferred embodiment of the device for predicting the elastic modulus of a wood composite laminate described in the present invention, the vibration excitation element is fixed to the surface of the wood composite laminate to be tested by an adhesive, and the wood composite laminate to be tested is suspended and in a free state.

[0009] As a preferred solution of the device for predicting the elastic modulus of a wood composite laminate described in the present invention, the signal acquisition device includes an acceleration sensor and a data acquisition card, the acceleration sensor is fixed on the wood composite laminate to be tested, and the data acquisition card is connected between the acceleration sensor and the data processing component.

[0010] As a preferred solution of the device for predicting the elastic modulus of a wood composite laminate according to the present invention, the data processing component is a host computer with built-in COMSOL Multiphysics software.

[0011] A method for predicting the elastic modulus of a wood composite laminate comprises the following steps: S1. Fix the vibration excitation element on the surface of the wood composite laminate to be tested, and suspend the wood composite laminate to be tested so that it is in a free state; S2. Applying a periodic mechanical force to the vibration excitation element through a piezoelectric drive device to generate a sinusoidal vibration signal, and transmitting the signal to the wood composite laminate to be tested to generate lateral vibration; S3, receiving the vibration signal of the composite plate unit through a signal acquisition device and transmitting it to a data processing component; S4. performing fast Fourier transform autospectral analysis on the sampled signal in a data processing component to obtain the first three natural frequencies of the predicted wood composite laminate; S5. Calculate the first three-order bending elastic moduli based on the relationship between the natural frequency and the geometric dimensions and material properties, and select the first-order dynamic elastic modulus as an input parameter of the finite element model; S6. Using finite element software to establish a geometric model that conforms to the predicted dimensions of the wood composite laminate, input the first-order dynamic elastic modulus, Poisson's ratio, and density, set the boundary conditions to two-terminal constraints, apply a linear load, mesh the model, and locally refine the stress concentration area; S7. Run the model, obtain stress and strain through post-processing, select the third principal stress and the third principal strain, perform volume integration on them respectively, and calculate the ratio of the volume integral of the third principal stress to the volume integral of the third principal strain as the predicted value of the elastic modulus.

[0012] As a preferred solution of the method for predicting the elastic modulus of a wood composite laminate described in the present invention, the finite element software adopts the solid mechanics module of COMSOL multi-physics field.

[0013] As a preferred embodiment of the method for predicting the elastic modulus of a wood composite laminate according to the present invention, the grid is an extremely fine grid.

[0014] As a preferred embodiment of the method for predicting the elastic modulus of a wood composite laminate according to the present invention, the elastic modulus is a bending elastic modulus.

[0015] Compared with the existing technology, the present invention has the following beneficial effects: the present invention proposes a rapid prediction technology for the flexural elastic modulus of wood composite panels based on finite element numerical simulation, which realizes non-destructive testing of the performance of each composite panel, avoiding physical damage and waste of resources; the present invention combines finite element analysis with a limited number of experiments, significantly reducing detection time and cost, and improving overall efficiency; the present invention ensures the reliability of material performance and improves the quality control level of building materials by efficiently evaluating the flexural elastic modulus of composite panels. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. Among them: Figure 1 This is a schematic structural diagram of a device for predicting the elastic modulus of a wood composite laminate according to the present invention; Figure 2 This is a schematic diagram of the finite element modeling provided by the present invention. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0018] The present invention provides a device and method for predicting the elastic modulus of a wood composite laminate, which combines finite element analysis with limited number of experiments, significantly reduces detection time and cost, and improves overall efficiency.

[0019] Figure 1 The figure shows a schematic diagram of an embodiment of a device for predicting the elastic modulus of a wood composite laminate according to the present invention. Figure 1 In this embodiment, a device for predicting the elastic modulus of a wood composite laminate includes: a vibration excitation element 100, a piezoelectric driving device 200, a signal acquisition device and a data processing component 500.

[0020] The vibration excitation element 100 is fixed on the wood composite board to be tested. Specifically, the vibration excitation element 100 is fixed to the surface of the wood composite board to be tested by an adhesive, and the wood composite board to be tested is suspended and in a free state. Preferably, in this embodiment, the vibration excitation element 100 is a piezoelectric chip.

[0021] The piezoelectric driving device 200 is connected to the vibration excitation element 100 and is used to apply a periodic mechanical force to the vibration excitation element 100 so that it generates a sinusoidal vibration signal; The signal acquisition device is installed on the wood composite board to be tested and receives the vibration signal of the tested composite board unit. Specifically, the signal acquisition device includes an acceleration sensor 300 and a data acquisition card 400. The acceleration sensor 300 is fixed on the wood composite board to be tested, and the data acquisition card 400 is connected between the acceleration sensor 300 and the data processing component 500. The data processing component 500 acquires the vibration signal transmitted by the signal acquisition device and performs data processing, analysis and prediction. In this embodiment, the data processing component 500 is a host computer with built-in COMSOL Multiphysics software.

[0022] Combine Figure 1 In this embodiment, a method for predicting the elastic modulus of a wood composite laminate comprises the following steps: S1. Fix the vibration excitation element 100 on the surface of the wood composite laminate to be tested, and suspend the wood composite laminate to be tested so that it is in a free state; S2, the piezoelectric driving device 200 is used to apply periodic mechanical force to the vibration excitation element 100 to generate a sinusoidal vibration signal, and the signal is transmitted to the wood-based composite laminate to be tested to generate transverse vibration; S3, the vibration signal of the composite laminate unit is received by the signal acquisition device and transmitted to the data processing component 500; S4, the sampled signal is subjected to fast Fourier transform and self-spectrum analysis in the data processing component 500 to obtain the first three order natural frequencies of the predicted wood-based composite laminate; S5, according to the relationship between the natural frequencies and the geometric dimensions and material properties, the first three order flexural elastic moduli are calculated, and the first order dynamic elastic modulus is selected as the input parameter of the finite element model, wherein the elastic modulus is the flexural elastic modulus; S6, a geometric model conforming to the size of the predicted wood-based composite laminate is established by using a finite element software, the first order dynamic elastic modulus, Poisson's ratio and density are input, the boundary condition is set as two end point constraints, the load is set as a line load, the model is meshed, and the local stress concentration area is refined, wherein the finite element software uses the solid mechanics module of COMSOL multi-physical field, and the mesh is an extremely fine mesh; S7, the model is run, the stress and strain are obtained by post-processing, the third principal stress and the third principal strain are selected and subjected to volume integration respectively, the ratio of the third principal stress volume integration to the third principal strain volume integration is calculated as the elastic modulus prediction value.

[0023] The above scheme and technical effects are described and verified in combination with a specific example as follows: The plate material is a wood-based composite laminate composed of three plates, two surface plates are made of beech, and the plate size (length x width x thickness) is 1000 x 50 x 3 mm; one core plate is a medium density fiberboard, and the plate size (length x width x thickness) is 1000 x 50 x 15 mm; the plate size (length x width x thickness) of the composite laminate is 1000 x 50 x 21 mm. The upper computer software for signal acquisition, analysis and processing uses DASP-V11 engineering version of Beijing Oriental Vibration and Noise Technology Institute, and the upper computer software for modeling uses COMSOL Multiphysics software of COMSOL, Inc.

[0024] S1, the piezoelectric wafer is fixed on the surface of the composite laminate unit to be tested using an adhesive, and then it is hung at the node using a thin rope to be in a free state; S2, the piezoelectric driving device is used to apply periodic mechanical force to the piezoelectric wafer to generate a sinusoidal vibration signal, and the signal is transmitted to the artificial board to be tested to generate transverse vibration; S3, receiving the vibration signal of the tested composite laminate unit through the acceleration sensor, and transmitting the signal to the host computer through the data acquisition card; S4. Select the corresponding sampling signal in the host computer data analysis software and use fast Fourier transform to perform autospectral analysis on the signal to obtain the first three natural frequencies of the tested composite laminate unit; S5. Based on the relationship between the natural frequency of the tested composite laminate unit and its geometric dimensions and material properties, calculate its first three-order bending elastic quantities and select its first-order dynamic elastic modulus as the input parameter of the finite element model. The first-order dynamic elastic modulus of the upper plate is 8.88 GPa, the first-order dynamic elastic modulus of the core plate is 2.44 GPa, and the first-order dynamic elastic modulus of the lower plate is 10.73 GPa. S6. Using COMSOL multi-physics solid mechanics module, a geometric model is established according to the size of the composite plate unit. The geometric model is as follows: Figure 2 As shown; S7, inputting the obtained first-order dynamic elastic modulus of the composite laminate element as a parameter, and simultaneously inputting the Poisson's ratio and density of the laminate element; S8. Add boundary conditions as two-end point constraints and apply load as line load; S9. Divide the mesh into very fine and perform local refinement on stress concentration areas; S10. Run the model, obtain stress and strain in post-processing, select the third principal stress and the third principal strain, and perform volume integration on them respectively. The volume integral of the third principal stress is -378.41 N*m, and the volume integral of the third principal strain is -7.60e-8m3; S11. The final predicted value is the ratio of the volume integral of the third principal stress to the volume integral of the third principal strain, 4.98 GPa.

[0025] The test results show that the finite element predicted value of the measured wood composite laminate is 4.98 GPa, which is highly correlated with the static flexural elastic modulus of 4.74 GPa obtained by the static three-point bending method.

[0026] Although the present invention has been described above with reference to embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present invention. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of such combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A device for predicting the elastic modulus of a wood composite laminate, characterized in that: include: A vibration excitation element (100) is fixed on the wood composite board to be tested; A piezoelectric drive device (200) is connected to the vibration excitation element (100) and is used to apply a periodic mechanical force to the vibration excitation element (100) so that it generates a sinusoidal vibration signal; A signal acquisition device is installed on the wood composite board to be tested and receives the vibration signal of the composite board unit to be tested; The data processing component (500) acquires the vibration signal transmitted by the signal acquisition device and performs data processing, analysis and prediction.

2. The device for predicting the elastic modulus of a wood composite laminate according to claim 1, characterized in that: The vibration excitation element (100) is a piezoelectric chip.

3. The device for predicting the elastic modulus of a wood composite laminate according to claim 1, characterized in that: The vibration excitation element (100) is fixed to the surface of the wood composite board to be tested by means of an adhesive, and the wood composite board to be tested is suspended and in a free state.

4. The device for predicting the elastic modulus of a wood composite laminate according to claim 1, characterized in that: The signal acquisition device comprises an acceleration sensor (300) and a data acquisition card (400); the acceleration sensor (300) is fixed on a wood composite board to be tested; and the data acquisition card (400) is connected between the acceleration sensor (300) and the data processing component (500).

5. The device for predicting the elastic modulus of a wood composite laminate according to claim 1, characterized in that: The data processing component (500) is a host computer with built-in COMSOL Multiphysics software.

6. A prediction method for the device for predicting the elastic modulus of a wood composite laminate according to any one of claims 1 to 5, characterized in that: Here are the steps: S1, fixing the vibration excitation element (100) on the surface of the wood composite laminate to be tested, and placing the wood composite laminate to be tested in a free state by suspending it; S2, applying a periodic mechanical force to the vibration excitation element (100) through the piezoelectric drive device (200), causing it to generate a sinusoidal vibration signal, and transmitting the signal to the wood composite laminate to be tested, causing it to generate lateral vibration; S3, receiving the vibration signal of the composite plate unit through a signal acquisition device, and transmitting it to a data processing component (500); S4, performing fast Fourier transform autospectral analysis on the sampled signal in the data processing component (500) to obtain the first three natural frequencies of the predicted wood composite laminate; S5. Calculate the first three-order bending elastic moduli based on the relationship between the natural frequency and the geometric dimensions and material properties, and select the first-order dynamic elastic modulus as an input parameter of the finite element model; S6. Using finite element software to establish a geometric model that conforms to the predicted dimensions of the wood composite laminate, input the first-order dynamic elastic modulus, Poisson's ratio, and density, set the boundary conditions to two-terminal constraints, apply a linear load, mesh the model, and locally refine the stress concentration area; S7. Run the model, obtain stress and strain through post-processing, select the third principal stress and the third principal strain, perform volume integration on them respectively, and calculate the ratio of the volume integral of the third principal stress to the volume integral of the third principal strain as the predicted value of the elastic modulus.

7. The method for predicting the elastic modulus of a wood composite laminate according to claim 6, wherein: The finite element software adopts the solid mechanics module of COMSOL multi-physics field.

8. The method for predicting the elastic modulus of a wood composite laminate according to claim 6, wherein: The mesh is an extremely fine mesh.

9. The method for predicting the elastic modulus of a wood composite laminate according to claim 6, wherein: The elastic modulus is the bending elastic modulus.

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