基于ADAMS和ABAQUS热磨机研磨木片断裂过程数值模拟

Crack Propagation Simulation of Hot Mill Grinding with Wood Based on ADAMS and ABAQUS

【目的】基于ADAMS和ABAQUS软件对热磨机研磨木片的断裂过程进行数值模拟,研究当动、静盘磨齿间的夹角α一定、木片到主轴中心的距离R变化时的场变量输出,从理论上分析磨片破碎区域面积对纤维分离能耗的影响,指导热磨机磨片的优化设计。【方法】结合断裂力学理论,基于数值模拟方法,取动、静盘磨齿间的夹角α=15°,运用ADAMS软件求解木片到主轴中心的距离R分别为370、390、410、430、450 mm 5种情况时木片所受的研磨压力F_m和剪切力F_r,并利用ABAQUS软件将所求得的力加载在木片上进一步模拟木片断裂过程。【结果】1)在热磨机动、静磨齿研磨压力F_m和剪切力F_r的作用下,木片发生断裂破坏,α=15°、R=450 mm时木片的Mises应力变化范围为9.846×10^(-2)～7.493 MPa,第一主应变变化范围为1.235×10^(-5)～2.546×10^(-2),第三主应变变化范围为-1.231×10^(-4)～-1.853×10^(-2),应变E_(23)变化范围为-3.481×10^(-2)～3.756×10^(-3),较大的应力应变主要分布在裂纹附近,木片左右两侧的应力应变逐渐减小。α=15°、R=450 mm时木片节点位移U_1的变化范围为-7.605×10^(-4)～1.693×10^(-3)mm,节点位移U_3的变化范围为-3.334×10^(-2)～1.966×10^(-2)mm,U_3的变化范围大于U_1的变化范围,木片主要沿U_3方向被撕裂,即木片在被研磨过程中主要在剪切力F_r的作用下沿木片横纹方向被分离。2)在磨片破碎区,当动、静盘磨齿间的夹角α一定时,木片到主轴中心的距离R增大,木片的Mises应力、正应力、Magnitude、节点位移呈增大趋势。当木片到主轴中心的距离R越大,即破碎区面积越大时,木片所受应力应变增大,木片断裂越容易。【结论】1)木片被研磨过程中主要在剪切力F_r的作用下沿木片横纹方向被分离,对磨片进行结构设计和优化分析时应尽可能增加磨齿对木片的剪切力F_r,使磨片破碎区木片的断裂程度更充分,降低粗磨区和精磨区的纤维分离能耗。2)热磨机研磨木片时木片到主轴中心的距离R越大,即破碎区面积越大,木片断裂就越容易,合理设计磨片破碎区域面积可以降低纤维分离能耗。3)运用ABAQUS软件模拟木片到主轴中心的距离R不等时的场变量输出,从理论上分析磨片破碎区域面积对纤维分离能耗的影响,可以指导热磨机磨片的优化设计。

【Objective】In order to improve the design of the mill grinding disc,the fracture process of grinding the wood chips into fibers by the hot mill was studied in this paper.Based on ADAMS and ABAQUS,the process of grinding the wood chips by the hot mill was numerically simulated,and the process of gradual fracture of the wood chips with the force was explored.When the angle between the grinding and grinding teeth of the moving and stationary discs is constant,the amount of field change was recorded for the distance R from the wood piece to the center of the spindle.The influence of broken area size of the grinding piece on the energy consumption of fiber separation was theoretically analyzed.【Method】Combined with the theory of fracture mechanics,the method of numerical simulation is used.When the angle between the teeth of the moving and stationary discsαis15°,the numerical simulation method is applied to solve the distance R between the wood chips and the spindle center by using ADAMS software to obtain R=370,390,410,430,450mm in five cases,the size of the grinding pressure F m and the shear force F r.Then use ABAQUS software to load it on the wood chip and numerically simulate the fracture process.【Result】The ADAMS software was used to simulate the working process of grinding the wood chips by the hot mill,and the simulation result of the grinding pressure Fm and the shearing force Fr of the wood chipsα=15°and R=450mm were obtained.The field variable output result ofα=15°and R=450mm were obtained by using ABAQUS software.The variation trend of Mises stress,normal stress,Magnitude and node displacement of wood chips under different conditions was studied by using Excel scatter plot and regression analysis chart.【Conclusion】1)The damage form of the wood chips during the grinding process is mainly separated by the shear force Fr along the transverse direction of the wood chips.Therefore,during the structural design and optimization analysis of the grinding plates,the grinding teeth should be increased as much as possible.The force of the cutting force Fr makes the fracture degree of the wood chip in the crushing zone more complete,and reduces the energy consumption of fiber separation in the rough grinding zone and the fine grinding zone.2)When the hot mill grinds the wood chips,the larger the distance R from the wood chips to the center of the main shaft,the larger the area of the crushing area,the easier the fracture of the wood chips is.The reasonable design of the area of the crushing area of the grinding plate can reduce the energy consumption of fiber separation.3)Using ABAQUS to simulate the field variable output when the distance from the wood chip to the center of the spindle is not equal,the influence of the area of the crushed area on the fiber separation energy consumption is theoretically analyzed,which can guide the optimized design of the grinding piece.