﻿ 工程案例式教学法在基础力学教学中的应用 The Application of Engineering Case Teaching Method in Basic Mechanics Teaching

Vol. 08  No. 05 ( 2018 ), Article ID: 26920 , 6 pages
10.12677/AE.2018.85092

The Application of Engineering Case Teaching Method in Basic Mechanics Teaching

Tongjie Li, Chuanping Wan, Zhongfang Li, Ruibin Gou, Liyong Zhang

College of Mechanical Engineering, Anhui Science and Technology University, Fengyang Anhui

Received: Sep. 4th, 2018; accepted: Sep. 18th, 2018; published: Sep. 25th, 2018

ABSTRACT

A teaching method called engineering case teaching method is proposed in this paper in order to solve some problems existing in the basic mechanics teaching. The method includes five specific teaching steps, namely engineering case discussions, posing questions, introducing the mechanical knowledge required to solve questions, problem solving, and summarizing. Students can more deeply understand the purpose and usage of mechanics knowledge according to the engineering case teaching method. Two advantages are analyzed which include improving the interest of the students on learning basic mechanics, and better adapting to the current situation of college about the reducing class hour of basic mechanics and students’ decreased mathematical foundation. Finally, taking the kinematics characteristics study of the shaper as an engineering case, the whole process of engineering case teaching for the velocity synthesis formula in the theoretical mechanics is demonstrated in this paper.

Keywords:Engineering Case Teaching Method, Basic Mechanics Teaching, Application Case

1. 引言

2. 工程案例式教学

1) 工程案例式教学可以极大地提高学生们学习基础力学的兴趣。笔者曾经跟授课学生深入交流过，发现学生们对基础力学不感兴趣的一个重要原因是不知道力学知识对他们的专业有何用处——现在的学生很现实，对于“没用”的东西自然不肯下功夫。倘若基础力学教师只是苍白地强调力学很重要而不告诉学生们为什么力学对他们很重要以及如何重要，那么学生们对力学重要性的认识是肤浅的，内心很难引起共鸣。通过工程案例式教学，学生们会真真切切地感受到力学知识对他们专业的重要性，激起他们学习力学知识的兴趣，变被动学习为主动学习。

2) 工程案例式教学方法与当前高校基础力学学时减少以及学生数理基础下降的现实是相适应的。工程案例式教学并不一味追求力学知识定理的理论严密性，而更专注于介绍力学知识在相关专业中能够干什么以及怎么干。在高校学生数理基础偏弱的现状下，这种弱化公式定理推导，专注公式应用，由特殊到一般的教学方法更容易被学生接受，而省略公式定理推导所节省的课时还可以弥补基础力学学时消减带来的不利影响。所以说，工程案例式教学方法与当前高校基础力学学时减少以及学生数理基础下降的现实是相适应的。

3. 面向机械专业的《理论力学》工程案例式教学示例

(一) 讨论

(二) 提出问题

(三) 介绍并引入解决问题所需要的力学知识

(1)

(四) 解决问题

1) 取套筒A为动点，动参考系与摇杆O1B固连。相对运动是套筒A沿摇杆O1B的直线运动，牵连运动是摇杆O1B绕O1的定轴转动，绝对运动是套筒A绕O的圆周运动。那么绝对速度的大小是：

${v}_{a1}={O}_{1}A\cdot {\omega }_{1}$ (2)

2) 按照定义，导杆机构的各速度矢量方向如图2所示，各未知速度分析如下式所示。

${v}_{e1}={v}_{a1}\mathrm{sin}{30}^{\circ },{\omega }_{{o}_{1}B}=\frac{{v}_{e1}}{{O}_{2}A},{v}_{r1}={v}_{a1}\mathrm{cos}{30}^{\circ }$ (3)

Figure 1. The mechanism motion diagram of shaper

Figure 2. Speed analysis of the guide bar mechanism

3) 取套筒B为动点，动参考系与滑枕CD固连。相对运动是套筒B沿滑杆的竖直直线运动，牵连运动是滑枕CD的水平平动，绝对运动是套筒B绕O1的圆周运动。按照定义，执行机构的各速度矢量方向如图3所示。

4) 由速度合成定理可得：

${v}_{a2}={O}_{2}B\cdot {\omega }_{{o}_{2}B},{v}_{e2}={v}_{a2}\mathrm{cos}{30}^{\circ }$ (4)

4. 总结及引申

Figure 3. Speed analysis of the actuator

Figure 4. A disperse motion period of the shaper

Figure 5. Simulation curves of the kinematics characteristics of planer tool

5. 结论

The Application of Engineering Case Teaching Method in Basic Mechanics Teaching[J]. 教育进展, 2018, 08(05): 573-578. https://doi.org/10.12677/AE.2018.85092

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