Discrete Element Simulation Analysis Of Material Crushing In Chewing Process

With the rapid development of China’s economy and the proportion of aging population increasing year by year,orthodontic and prosthodontic technologies have attracted extensive attention,leading to more and more problems related to denture detection,including large instrument consumption,high production cost and slow measurement speed.In order to overcome these problems,this paper constructed a digital model of food particles based on discrete element method and analyzed the chewing breakage.The change of chewing force of food particles in the chewing process was compared with the experimental data,so as to verify the feasibility of the chewing breakage model and provide data support for the detection of dentures.Discrete element method(DEM)is a numerical method to simulate the substitution of small particles for large particles.In daily life,most of the material properties of food belong to discrete particles,so in the simulation of chewing food,the food particles constructed by discrete element method are more consistent with reality.The main research contents of this paper include:(1)Reconstruction of 3D dental model.In this paper,CT tomography technology was used to take the teeth of healthy adult men as samples,and the subjects were scanned from the mandibular base to the nasal bone.The first upper and lower molars of healthy adults were taken as reference,and the reconstructed 3D tooth model was obtained by reverse engineering technology.(2)The acquisition of food particle parameters.The particle bonding model in discrete element method is used to simulate the state of food crushing under the action of external forces.In this paper,the particle cluster model is used to study the changes of food crushing forces.Discrete element bonding model(BPM)was used to fill the 3D model of food with particles.The 3D digital model of teeth in the oral cavity and jaw was studied as the chewing boundary.(3)Design of masticatory experimental platform.Through the motion capture experiment,the cutting and grinding motion track of the oral and maxillary system can be effectively obtained when the experimental object is chewing food normally.The Matlab software is used to analyze the data of the track,and the motion function under two motion states can be obtained,which is used as the driving variable of mandibular teeth to ensure the authenticity of the simulation motion.A variable trajectory four-bar mechanism was designed based on trajectory planning of the trajectory data,which could meet the chewing mechanical characteristics that could not be realized by the multi-degree-of-freedom chewing robot.Therefore,the experimental device of chewing material crushing was further designed.(4)Verify the feasibility of chewing and crushing model.In ADAMS software,the motion track obtained from the motion capture experiment was taken as the driving function of the jaw,and the ADAMs-EDEM coupling simulation was carried out on the 3D model of soybean with different chewing speed under the cutting and grinding motion modes respectively,and the simulation data was analyzed.Under the premise of the same variables,experiments were compared with the designed experimental device to verify the feasibility of the chewing and crushing model,and provide data support for the future study of the reliability of denture and bionic jaw frame.