Rationale: Adenoid cystic carcinoma (ACC) is the most common malignant epithelial tumor of the lacrimal gland with the highest malignant degree. ACC of the lacrimal gland is characterized by symptoms of <1 years duration. We present a 38-year-old male patient who complained of an enlarging mass in the left lacrimal fossa for almost 10 years previous to the diagnosis of ACC. Patient concerns: A 38-year-old male patient visited our ophthalmology clinic with a chief complaint of a mass in his left upper lid, which had enlarged significantly over the previous months. Diagnoses: Magnetic resonance imaging with intravenous Gadobutrol showed moderate and homogenous mass enhancement. Bone destruction is found. The periosteum is not eroded. The magnetic resonance imaging finding was supportive for malignancy. Histopathological examination of the specimen revealed solid tumor showing a cribriform pattern mixed small amount of basaloid cell proliferation. Therefore, the final diagnose was Adenoid cystic carcinoma of the lacrimal gland. Interventions: The treatment included en bloc resection of the mass and adjacent bone and radiotherapy. Outcomes: In 1 year follow-up after operation, there is no recurrence. Visual acuity is 30/30. The left eye shows limitation on abduction. Lessons: The present case demonstrates an unusual progression of ACC of the Lacrimal Gland.

Torsional resistance is an important mechanical property of the shaft. The traditional torsional resistance measurement is based on the deformation of the strain gauge, which needs to be attached to the shaft under test. When the inner diameter of the hollow shaft is small, the stress measurement error of the inner wall of the shaft will be very large because the strain gauge has a certain size. To solve this problem and obtain more accurate data, this study adopts the finite element model simulation method to calculate the torsional resistance of a hollow shaft with a small diameter. The 3D finite element model is built and computed on the server. Rich data and colorful nephograms are acquired. The results show that the stress value of the same position increases with the increase of torque. When the torque is 6 kNm, the shaft is plastically deformed, and the maximum Mises stress reaches 432.2 MPa. The maximum Mises stress occurred on the outer surface of the shaft. When plastic deformation occurs on the outer surface, the stress on each part of the shaft increases. Finite element modeling and simulation can obtain rich data and visual nephograms, which is very helpful to the research of torsional resistance of shaft.

Hollow shaft is widely used in aviation, vehicle, construction, electrician, and other fields. Bending-torsional resistance is one of the most important mechanical properties of the hollow shaft. The traditional test has a long testing time, high cost, and strict requirements on the sample size. In addition, it is difficult to measure the stress in special areas, such as the inner diameter of the hole and narrow gaps, because the strain gauge has a certain size. To solve this problem, a three-dimensional finite element model was established to study the bending-torsional resistance of the hollow shaft. The color stress nephograms and rich data are obtained by simulation. The results showed that Mises stress of the hollow shaft increased with the indenter pressure. However, this increase is slowing down. The maximum Mises stress of the shaft reached 497.6 MPa when the pressure was 40 kN. The maximum Mises stress occurred at the position where the shaft contacted the base. Using simulation techniques to study the bending and twisting resistance of the hollow shaft is feasible.

The problem of poor teaching effect of tensile experiment in Material Mechanics course in higher vocational colleges has existed for a long time. In order to solve it, the research team put forward a method of using modeling and simulation to obtain materials such as pictures, animations, so as to improve the teaching effect. A 3D finite element model for tensile experiment was established and conducted calculations on a computer. The simulated animations visually showed the necking and cracking behavior of the specimen under tension, and the Mises stress nephograms clearly showed the stress distribution of the specimen at different time points. In addition, a large amount of data has been calculated. The Mises stress nephograms and animations were used as course materials of Material Mechanics. The beneficial effects of simulation materials are mainly reflected in: (1) the unfamiliar concepts, such as neck contraction and fracture, are easier to be understood by students, and the teaching quality is improved; (2) it stimulates students' interest in learning; (3) the model simulation and demonstration are done on a computer, which not only has no danger, but also saves the experimental cost. The research idea should be applied in more courses of higher vocational education.

Many knowledge points of Material Mechanics are abstract and difficult to understand for students in vocational colleges. In practical teaching, some students questioned the torsional resistance formula of hollow shaft. In order to solve students' learning doubts, this paper proposes a solution using modeling and simulation. The students and the teachers divided the work. Geometric model modeling and data analysis are completed by the students, while finite element modeling and simulation calculation are completed by the teachers. The Mises stress nephograms obtained by simulation calculation provide data to support the students' understanding, and completely solved the students' doubts. In addition, the students' analysis ability and data processing ability have been improved and exercised in the process of problem solving. Finite element modeling and simulation can provide a good solution to the doubts of students in vocational colleges, which is worth exploring by more scholars.