A Practical Graphical Approach for Drawing Shear Force and Bending Moment Diagrams

摘要

The ability to draw shear force and bending moment diagrams on beam-like components is an important skill for mechanical engineering students. We found that some students had difficulty to draw effectively the shear force and bending moment diagrams during the course and even in their senior year. Although the method of sections can produce all for drawing the diagrams, it becomes tedious when a beam is divided into several segments. The graphical approaches by free-hand sketch are discussed in every textbook and is a good approach for drawing the diagrams. But the procedures provided in textbooks are not easy to be followed effectively by students and could be improved. Many computer-based or similar programs for drawing the diagram are available, but their effectiveness is not validated by proper assessment. We had studied this issue in the past years and had developed a practical procedure for drawing the diagrams with a free-hand sketch in 2017. In the spring and fall semesters 2017, the proposed procedure was implemented successfully in different sections of Mechanics of Materials course. The proposed procedure for drawing the diagrams was assessed by a quiz given to different sections of the course. The feedback information was collected through the class survey. Based on the assessment and class survey, most students liked the proposed procedure and believed the method was practical. The assessment based on the quiz also showed the grades with the proposed procedure were significantly improved. This paper presents the practical graphical procedure for drawing the diagrams as well as the results of the class survey and the assessment.