Steif, P. S., & Dollar, A. (2005, June), Sharpening Statics As A Tool For Design: Demystifying The Modeling Of Forces At Connections  Paper presented at 2005 Annual Conference, Portland, Oregon. 10.18260/1-2--15322

\bibitem{asee_peer_15322}
  Steif, P. S., \& Dollar, A. (2005, June), \emph{Sharpening Statics As A Tool For Design: Demystifying The Modeling Of Forces At Connections}
  Paper presented at 2005 Annual Conference, Portland, Oregon.
  10.18260/1-2--15322

Paul S. Steif and Anna Dollar.  "Sharpening Statics As A Tool For Design: Demystifying The Modeling Of Forces At Connections".  2005 Annual Conference, Portland, Oregon, 2005, June.  ASEE Conferences, 2005.  https://strategy.asee.org/15322 Internet.  25 Jun, 2024

\bibitem{asee_peer_15322}
  Paul S. Steif and Anna Dollar.
  "Sharpening Statics As A Tool For Design: Demystifying The Modeling Of Forces At Connections".
  \emph{2005 Annual Conference, Portland, Oregon, 2005, June}.
  ASEE Conferences, 2005.
  https://strategy.asee.org/15322 Internet.  25 Jun, 2024

@INPROCEEDINGS{asee_peer_15322
author = "Paul S. Steif and Anna Dollar"
title = "Sharpening Statics As A Tool For Design: Demystifying The Modeling Of Forces At Connections"
booktitle = "2005 Annual Conference"
year = "2005"
month = "June"
address = "Portland, Oregon"
publisher = "ASEE Conferences"
note = {https://strategy.asee.org/15322}
number = {10.18260/1-2--15322}
}

TY  - CPAPER
AB  - Statics is an early, critical step in preparing engineers, persons who can bridge the gap between
fundamental concepts of physics and the analysis and design of real mechanical and structural
systems. Students struggle with many concepts in Statics. We propose here that the modeling of
supports, joints or connections between bodies is one of the most difficult and important ideas to
be grasped in Statics. Moreover, it is probably at the core of linking physics with real
mechanical and structural systems. The notions of force and equilibrium can be dealt with in
purely mathematical ways, until one is compelled to associate forces with the actual interactions
between particular bodies. Doing that correctly is not easy for students, and yet it is critical. We
suspect that continuing difficulties in applying Statics in upper level design courses is at least
partially tied to weaknesses in this area.
We have previously criticized various aspects of traditional instruction in Statics. The subject of
connections, in particular, typically receives cursory treatment in textbooks, as exemplified by
the tables showing idealized drawings of joints and the unknown “reactions”. Traditional statics
courses and textbooks are essentially teaching the analysis of forces for “pre-modeled”,
simplified situations. Moreover, these situations are neatly separated into two- and threedimensional
cases often covered in separate chapters. In reality, all mechanical and structural
systems are three-dimensional; it is up to the engineer to decide if a two-dimensional analysis is
warranted.
To its detriment, we believe, traditional instruction in Statics also tends to minimize any
reference to motion. Clearly, motion is tacitly present in problems that are often legitimately
analyzed using Statics, including, for example, slowly moving mechanisms, and gears and shafts
rotating steadily at high speeds. Reference to motion is clearly necessary if we are to explain to
students the purpose of many connections: to accommodate certain motions between parts while
precluding other motions. Noting the relative motions that are allowed and prohibited is also obviously one way of tracking and rationalizing which reactions can be present in different types
of connections.
Only if students are familiar with the essential features of connections, we would argue, can
they: (i) recognize the various physical realizations of connections, (ii) understand the possible
forces acting between connected members, and (iii) model the forces appropriately. With this
premise, we propose significant enhancements to instruction pertaining to connections. These
enhancements highlight the various roles that connections play in machines and structures,
rationalize in a deeper way the relation between possible forces and physical characteristics of
connections, and even empower students to draw their own conclusions regarding the virtues of
certain designs over others.
We fully recognize that most instructors devote relatively modest time to connections, probably
referring students to the tables in books. For the reasons suggested above, however, we suggest
that mechanics instructors reconsider this allotment of instructional time. To make enhanced
attention to practical connections, we have begun to devise appropriate elements of instructional
content. This content is suitable for a Statics course, and could allow for the generation of
specific educational materials, such as textbooks and in-class instructional materials. In the
following sections of the paper we address earlier experiences in our Statics sequence that can
prepare students for understanding connections, followed by excerpts from the newly developed
content.
AU  - Paul S. Steif
AU  - Anna Dollar
CY  - Portland, Oregon
DA  - 2005/06/12
PB  - ASEE Conferences
TI  - Sharpening Statics As A Tool For Design: Demystifying The Modeling Of Forces At Connections
UR  - https://strategy.asee.org/15322
DO  - 10.18260/1-2--15322
ER  -