Objective To construct a finite element model of a miniature pig’s mandibular angle fracture with simulated

installation of a self-developed external fixation device at the fracture site， and to analyze the device’s biomechanical performance by three-dimensional finite element technology， thereby laying a foundation for clinical application. Methods A healthy Bama miniature pig weighing 20 kg was selected for cranial CT scanning. The scanned DICOM data were imported into Mimics for cranial three-dimensional reconstruction. The STL file was then imported into Geomagic Studio software to complete geometric reverse modeling. The resulting IGES file， a universal surface geometry file， was imported into Solidworks software to set up a virtual fracture at the mandibular angle. At the same time， the data of the self-developed mandibular external fixation device was imported into the Solidworks software for three-dimensional reconstruction， and a simulation installation was carried out at the fracture site of the mandibular angle. The IGES data of the mandible and the data of the external fixation device were imported into ICEM software for meshing to generate an UNS mesh file， which was then imported  into Workbench software to analyze the stress and strain changes of the mandible and the external fixation device under a certain load. Results Three-dimensional finite element analysis revealed that after applying a vertically downward 196 N load at the first molar fossa of the right mandible， the maximum principal stress generated on both sides of the mandibular angle fracture ends was less than the ultimate strength of the mandible，103 MPa. The location of maximum Von-Mises stress of the screw was above the posterior end of the fracture， approximately 244.24 MPa. The location of maximum Von-Mises stress of the nut was also above the posterior end of the fracture， approximately 107.38 MPa. The location of maximum VonMises stress of the plate was at the screw hole below the anterior fracture end， approximately 138.54 MPa. The screw material  was medical stainless steel 00Cr18ni14mo3， with an ultimate strength of 860 MPa. The nut and plate material was titanium alloy Tc4， with an ultimate strength of 895 MPa. The stresses produced by the three structures of the external fixation device were all below the ultimate strength of its material. The overall deformation of the external fixation device was 0.861 mm， and the strain was small. Conclusion The models of the mandibular angle fracture and the external fixation device of the miniature pig established using medical digital imaging software and three-dimensional finite element software have high simulation accuracy and can provide multiple simulation experiments. According to the results of the three-dimensional finite element analysis， the selfdeveloped external fixation device for the mandible can achieve rigid fixation of the miniature pig’s mandibular angle fracture.

External fixation device, Mandibular angle fracture, Finite element analysis