# User:Eml4500.f08/HW report table/The best of HW7

Under construction; not final (but close to being stable after a couple of weeks). The intention here is to document the best features in any HW report for the readers (including you); if you see excellent features in any HW report (including your team's) that I may have missed noticing, don't hesitate to let me know. I don't have time to read all HW reports in detail. In fact, due to time constraint, I only selectively looked at a few important features. On the other hand, I also added some annotations (e.g., related to errors) in the HW reports that I looked through for the benefit of everyone. Eml4500.f08 21:26, 9 December 2008 (UTC)

• 2-D frame elements (truss + beam)
• 2-D frame model problem
• FBDs
• element dofs: displacements, rotations
• assembly of element stiffness matrices into global stiffness matrix
• element stiffness matrix $\displaystyle \tilde \bold k ^{(e)}$ in local coordinates
• dimensional analysis of element stiffness coefficients $\displaystyle \tilde k ^{(e)}_{ij}$
• transformation of FD relation from local coordinates to global coordinates
• PVW for elastodynamics of beams
• stiffness term
• shape functions for truss and for beam
• true deformed shape of a frame element (truss + beam)
• disp components in global coordinates for a point on a frame element in terms of element dofs
• dimensional analysis of shape functions and overall relation
• derivation of beam shape functions
• elastodynamics of trusses, frames, 2-D, 3-D elasticity
• discrete equations of motion (MDOF; coupled ODEs) and initial conditions
• unforced vibration problem
• eigenvalue problem: derivation
• generalized eigenvalue problem
• standard eigenvalue problem
• mass orthogonality property
• stiffness orthogonality property
• decouple system of equations of motion into uncoupled ODEs
• recommended software to improve productivity. Most useful: Team Bike
• writing wiki articles
• writing latex equations
• drawing figures
• Mediawiki (on Wikiversity) vs. WebCT (on E-learning at UF): To set the proper context for this section, I included below my original e-mail requesting a team consensus on a comparison between Mediawiki vs. WebCT. Best team-consensus comparison: Team Bike. NOTE: Team Delta_6 (with annotations), parallel non-cooperative individual work and comparison. General comment: Non-cooperative work. Some teams even admit that they never met together as instructed per cooperative learning techniques, with each team member taking turn to work on a lecture. Team Aero (with annotations): "the scope of collaboration did not extend as far as was perhaps intended. In general, the assignment was divided based on lecture days and each person made their own posts with little editing." There was not much of a cooperation. Here is a most-telling example. The result is often a mosaic of incoherent pieces put together, without a flowing story. Absenteism and workload. If each student (in a typical team of six) did 1/6 of the work, took care of one lecture once every two weeks, but received 34% credit for the course grade, and yet did not attend all lectures, it is not clear why some of these students said that there was too much work, and what they would use the rest of their freed-up time for !? At least, Mediawiki allowed some students to free up their lecture attendance. Young Einstein was famous for skipping his classes (for thinking about physics), and learned from the math notes of his friend, but he was one in a billion... It would be a wild stretch of imagination to think that we had a Young Einstein in the class... Students who regularly attended lectures would do better in exams than they potentially could otherwise, regardless of their own level. Lecture notes taking seems to be a lost art with in the digital age of powerpoint presentations. While many students continued to take good notes (and even scanned them to e-mail out to their teammates who did not attend lectures), many others just relied either on their teammates' notes, the textbook (some lectures cannot be found in the textbook), or the digital photos they took of my transparencies (hand-written in real time in class) using their cell phones, even though I mentioned in class that it was not possible to do math or mechanics without writing, and did referred to the effect of writing on remembering that I read in Carl Sagan's The Dragons of Eden.
• collaboration
• parallel team work across the internet
• math equations
• incorporation other media (video, audio)
• accessibility
• matlab problem graded over 100%
• 2-bar truss system
• uniform bar elements
• tapered bar elements
• comparison of deformed shapes
• 2-element frame system
• boundary conditions: clamped, hinged
• plot of complete (true) deformed shape
• comparison with 2-bar truss system
• electric pylon problem
• frame model (instead of truss model)
• finite element analysis
• plot undeformed and deformed shape
• compare to deformed shape of truss model
• frame element with highest nodal bending moment
• frame element with highest transverse shear force
• frame model statically determinate?
• compute reactions from frame model
• compare to reactions from truss model
• vibration analysis
• lumped mass matrix
• generalized eigenvalue problem
• lowest three eigenpairs
• compare with 3 lowest eigenvalues of truss system
• Results: eigenvalue (period in seconds)
• Team Bike 132.86 (0.54511 s), 2471.2 (0.12639 s), 2942.6 (0.11583 s); very close to those of the truss model; see The best of HW6; at least 3 teams got the same results.
• Team ATeam(Sean) (0.54511 s), (0.12639 s), (0.11583 s); too close to those of the truss model (0.54654 s), (0.12647 s), (0.11587 s); at least 3 teams got the same results.
• Team Delta_6 (with annotations) (0.54511 s), (0.12639 s), (0.11583 s); same comments.
• plot lowest three eigenvectors: animate these 3 modes. Best animation: Team Bike (gif file) Team ATeam(Sean) (video file)

EAS 4200C, The best of HW7