Design And Research Of Online Measurement System For Dynamic Modulus Of Bamboo-wood Panels

Bamboo-wood panels refer to the composite panels made of bamboo and wood in the form of the same or different structural units.As a raw material,bamboo-wood panels are widely used in the production of furniture,floor and engineering decoration.Due to the different materials and densities of bamboo and wood,these differences will affect the performance of bamboowood panels.Elastic modulus and shear modulus are important physical parameters of bamboo and wood,and also important parameters to evaluate the mechanical properties of bamboo and wood.In order to rapidly and nondestructively determine the dynamic elastic modulus and dynamic shear modulus of bamboo-wood panels,an online detection system based on FPGA is designed to measure the dynamic elastic modulus and dynamic shear modulus of bamboo-wood panels,and then compare with the static test to verify the test results.This paper mainly builds an online detection system for the dynamic modulus of bamboowood panels and compares it with the static method.The main work is as follows:(1)The ATSM E1876 standard was selected as the measurement method,and the finite element simulation software COMSOL Multiphysics was used to simulate bamboo-wood panels.The simulation results show that the dynamic elastic modulus and dynamic shear modulus of bamboo-wood panels can be measured effectively by using this method.(2)The system adopts the design scheme of "combination of soft and hard ",takes the DE10-nano development board of Altera CycloneⅤ series as the design platform,and Nios II soft-core processor as the core to build a dynamic modulus detection system for bamboo-wood panels.By selecting the resistance strain gauge sensor to pick up the plate excitation signal,the signal is amplified and then sent to the analog-to-digital conversion module of the FPGA development board.In the construction of system hardware module,ADC module,JTAG,RAM,PLL,PIO module,etc.,are designed and configured.Qsys is used to connect Nios II soft-core processor and related configuration modules,and related pin allocation is carried out.In the design of the system software module,the frequency spectrum transformation,the acquisition of the first order modulus and the calculation of the modulus are realized by C language programming.(3)The QT software is used to design the interface of bamboo-wood panels dynamic modulus detection system,to achieve human-computer interaction function,convenient for users to use.Its main functions include: start signal acquisition,spectrum transformation and calculation of dynamic modulus.(4)In order to verify the feasibility of the system,the measurement results of the system are compared with those of static methods,such as mechanical failure method.The relative errors of the elastic modulus and shear modulus are between 0.14%-2.59% and 0.32%-7.45% respectively.The measured data show that the system can accurately measure the dynamic elastic modulus and dynamic shear modulus of bamboo-wood panels.This system mainly uses FPGA development board to build measurement system,complete signal acquisition and amplification,analog-to-digital conversion,spectrum transformation,firstorder mode acquisition,modulus calculation,QT interface and overall hardware system construction design,and test its overall function in the actual environment.By comparing with the measurement results of mechanical failure method,it is proved that the dynamic modulus online detection system can effectively measure the dynamic elastic modulus and dynamic shear modulus of bamboo-wood panels.The processing speed is fast,the application is flexible,the stability is strong,and can meet the real-time detection requirements of the production process.