# Investigation of Roller Press Surface and Stud Based on FEM Simulation
## 3 FEM Simulation
### Contact Analysis of Stud-Lining
#### 3.2.1 Simulation Analysis of Studs and Stud-Lining
In order to study the maximum stress of the stud, the nip angle of the load is selected as 0\({}^{\circ}\), the pressure angle is perpendicular to the stud upper surface, the pressure value is taken as an integer as 120 MPa, and constrain the studded rolls model. The equivalent stress results are shown in Figure 9a-d below. Figure 8: Maximum equivalent stress of rolls surface and stud at different nip angle. Figure 7: Schematic diagram of compression zone and rebound zone of studded rolls. According to the data statistics, gap value is 0.08 mm and the maximum equivalent stress is 377.06 MPa. The gap value is 0.10 mm and the maximum equivalent stress is 425.31 MPa. The gap value is 0.12 mm and the maximum equivalent stress is 448.69 MPa. The gap value is 0.14 mm and the maximum equivalent stress is 461.09 MPa. Through the above data, it is found that with the increase of gap amount, the maximum equivalent stress presents a trend of gradually increasing muscle, but the increasing range gradually decreases. It can be found from the total deformation cloud diagram of the stud-lining and stud in Figure 9a1-d1 that the total deformation gradually increases as the gap value increases. The variation range of the total deformation value is 0.002 mm. The maximum total deformation occurs at the upper surface of the stud. The deformation on the stud-lining mainly occurs at the spherical bottom of the stud hole. Four sets of interference values of 0.02 mm, 0.06 mm, 0.08 mm, and 0.10 mm are selected in the reference, and the interference fit will be analyzed according to the same loading and constraint methods in clearance fit. According to the data statistics, the interference value is 0.02 mm and the maximum equivalent stress is 304.4 MPa. The interference value is 0.06 mm and the maximum equivalent stress is 724.8 MPa. The interference value is 0.08 mm and the maximum equivalent stress is 981.7 MPa. The interference value is 0.1 mm and the maximum equivalent stress is 1225.1 MPa. As the interference value increases, the maximum equivalent stress of the stud and stud-lining gradually increases. The stress is mainly concentrated in the upper part of the stud hole. As shown in Figure 10a-d. It can be found from Figure 10a1-d1 that the change trend of the total deformation of interference fit is the same as the change trend of stress. The maximum total deformation occurs on the stud-lining. The maximum total deformation occurs on the stud-lining. The deformation on the stud is mainly concentrated on the lateral cylindrical surface of the stud. The absolute value of the difference between the stud and the stud hole is taken as the \(X\)-axis, and the maximum value of the equivalent stress on the model is taken as the \(Y\)-axis, as shown in Figure 11. It can be seen from Figure 11 that with the increase of the difference, the maximum equivalent stress on the model gradually increases, and the growth rate of the interference fit is the largest. Figure 9: Cloud diagram of (**a–d**) equivalent stress (**a1–d1**) total deformation of stud-lining and stud with different gap values. It can be found that the change of interference fit is similar to that of clearance fit, showing a gradual growth trend, and the growth range is larger. In the case of the same value, the maximum equivalent stress of the post studded rolls of the interference fit is much larger than that of the clearance fit. Therefore, the gap assembly method is better than the interference assembly method. (3) Stress changes in different axial and circumferential distances  
Through reading the literature, it is found that the arrangement of the stud on the studlining surface has a great influence on the wear of the stud-lining of the stud [11, 26]. In order to explore the influence of different arrangements of studs on stress and deformation, a finite element model was established through ANSYS to change the axial and circumferential distances between two studs. Where the axial distance is set to x and the circumferential distance is set to y.