Top 5 Course Projects 2023/24 QII

2023/2024 Q2 Universitat Politècnica de Catalunya - BarcelonaTech (UPC)

Posted by | Milad Soltanalipour | 2024/07/09

Recently, the final project of the Course Strength of Materials for Industrial Technologies and Economic Analysis students in ETSEIB, UPC BarcelonaTech have been evaluated, with a multiple criterion system considering: Theory, design, build, test, and report quality.

In this post; the Top 5 Course Projects are introduced, and other relevant observations have been mentioned. The objective is to inspire future students of this subject by providing them with additional information about the previous course projects.

Wooden beam with steel reinforcement

Maria Buscallà, Jordi Edo

10 out of 10

Double-Cylindrical section

Victor Rafel, Guiu Rebagliato

10 out of 10

Wooden beam with variable section

Xavier González, Berta Roviró, Nerea Sarrió

9.30 out of 10

Variable steel T section with Advanced FEA

Oriol Codony, Pablo Miró, Marc Solans

9.29 out of 10

Semi-Circular PLA beam

Javier Albácar, Andreu Fitó, Alvaro García-Valdecasas

9.28 out of 10

Theory

The projects have been evaluated first regarding their theoretical analysis. The theory part of a report should consists of basic theory concepts, i.e., bending moment, shear force and normal force diagrams; critical cross-section, safety factor, failure load and displacement calculations. Moreover, if applicable, weld calculation and displacements related with the case of variable cross-section are evaluated.

Performing a Finite Element Analysis (FEA) can lead to receiving additional marks. It is an optional but a highly recommended task, which allows further validation of hand calculations.

The FEA works delivered by GTIAE students in this semester 2023/24 QII can be classified in three types, i.e., Thin-walled sections (shell elements); Structural solids (solid elements) and Beam structures (beam elements). Figure 2 shows the FE models developed by student groups; corresponding to the said categories.

Figure 1. Thin-walled section, Nicolás, Oliver, María

Figure 2. Structural solid, Oriol, Pablo, Marc

Figure 3. Beam structures, Victor, Guiu

Design

Another criteria has been the design of the beam, i.e. cross-section geometry; shape of structure and the degree of efficiency. The cross-section can be Solid (e.g., rectangle valid only if variable) Thin-walled (e.g., I or T sections etc.) or innovative. As an example of innovative cross-section, Figure 3 and 4 show a Double-Cylindrical section and I section reinforced on web-to-flange connection.

Figure 3. Double-cylindrical section, Victor, Guiu

Figure 4. I section reinforced on web-to-flange connection, Víctor, Valentina, Ana

Shape of the structure

The beam spans 500 mm (i.e., distance between supports); needs to avoid a pair of box-shaped obstacles between supports. Given this, a simple solution (straight beam) is not geometrically possible. The structure can pass between the obstacles, below or above them, but the length of a straight segment cannot exceed 400 mm.

Looking at the projects delivered in this semester by GTIAE students; the shapes of the structure can be classified into two types: Typical (trapezoidal) and Curved. A curved beam can be a challenge for the student teams, when it comes to construction. It can be printed as curved (see Figures 8 and 9), or it can be created by bending if the structure is of steel, for example. In this case, alternatively; a curved beam can also be created with connecting several straight segments.

Figure 5 and 6 show the construction procedure of Double-Cylindrical cross-section beam, which consists of two curves. The construction procedure starts with filling in the steel tube(s) with sand, closing the ends, and then bending the tubes to create the desired arcs. By filling in the tubular section, its instability to local buckling can be avoided. The steel has permanent deformation (due to bending) and it leads to a more brittle stress-strain relationship of the material in the curved zones. This effect can be taken into account by simply increasing the safety factor, accounting for the brittleness of the curved zones.

Figure 5. Sand-filling the tubes, Victor, Guiu

Figure 6. Curvature of the tube, Victor, Guiu

Degree of Efficiency (D.O.E)

The projects have been compared regarding their Degree of Efficiency (D.O.E). It has been defined as the ratio of Nominal load (P) / Own weight (w). Figure 7 shows the D.O.E ratio in order of magnitude. The 5 projects with a higher efficiency are made of wood and P.L.A (3D printing) materials.

It is worth noting that the selection of material has no effect on the mark, but it comes into play when the efficiency is determined: The lighter and more resistant the structure is, the higher mark it receives, regardless of the material chosen.

Figure 7. Degree of Efficiency (D.O.E) of course projects, semester 2023/24 QII, Strength of Materials

Build

The construction of the structures is either carried out on workshops or by students team. In both manners, descriptions of the construction procedure are valued. These descriptions can include pictures, technical drawings and or videos (e.g., in Time Lapse). Building the structure by students themselves is taken into consideration positively, when evaluating the work. Getting hands dirty and facing with real problems help to practice team-work skills, project management and to be more creative.

In this semester 2023/24 QII; students have gone through 3D printing technology more than the past. As some examples, Figure 8 and 9 show how the direction of printing needs to be set properly to obtain the expected mechanical properties; and Figure 10 shows how a Lego Joint has been designed by students team to connect two pieces of PLA printed.

Figure 8. Correct orientation of printing, Javier, Andreu, Alvaro

Figure 9. Incorrect orientation of printing, Javier, Andreu, Alvaro

Figure 10. Lego Joint to connect two pieces of PLA printed, Javier, Andreu, Alvaro

Test

It is expected that the structure resists a nominal load. This load differs for each group, which indicates that every project can be identical (considering together with other problem variables). The predicted deflection and the cause of failure are compared with the corresponding experimental observations. Before testing, the outline shape of the structure is drawn, and it is used as a reference (undeformed shape) for comparison. Figure 11 shows examples of undeformed/deformed shapes of a group in this semester 2023/24 QII of Strength of Materials course.

Figure 11. Undeformed/deformed shapes of structure, Mar, Mireia, Pawel (up) Victor, Guiu (down)

It can be noted that aesthetic aspects have no effect on the grade. But; who does not like to see a final project colored in Red or with a Lion face in its Y-Z plane? (see Figures 10 and 11)

Last but not least, I am very grateful for the opportunity to work with extraordinary students, talented, passionate about Strength of Materials, and creative.

Figure 12. Inverted T, Nicolás, Oliver, María

Figure 13. Lion face in Y-Z plane, Xavier, Berta, Nerea

Figure 14. Wooden beam with variable section, Xavier, Berta, Nerea

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