Design, analysis and application of innovative connections for optimized steel trusses

Design, analysis and application of innovative connections for optimized steel trusses: Structural behavior of innovative joints based on snap-fit connections

Abad Gonzalez, Jose Antonio (TU Delft Civil Engineering and Geosciences)

van der Linden, L.P.L. (mentor)
Schipper, H.R. (graduation committee)
Messali, F. (graduation committee)

Delft University of Technology

Civil Engineering | Building Engineering - Structural Design

2020-10-16

Steel trusses are the preferred structures when large distances are required to span due to its lightweight, the reduced deflection and its load bearing capacity. Although nowadays with the help of computational tools more efficient designs can be achieved, the geometrical shape of trusses has barely changed. This is mainly due to the ease of the required structural calculations and due to the available standard manufacturing and assembly procedures. Although a standard shape could be seen as an advantage, studies suggest that the relationship between the efficient use of material and design rationalization is not balanced, leading to design-overcapacity of the structure. The use of optimization procedures provides new opportunities to engineers. New design solutions and near-optimal structures can be achieved when implementing optimization processes. Optimization processes could generate economical alternatives in terms of weight reduction. Despite optimization techniques are becoming increasingly available, optimized structures are not commonly used in real practice due to the complex configuration an optimized structure might have, especially when using layout optimization. Due to the non-conventional node-members configuration, realizing these optimized trusses in real practice with conventional joining mechanisms, such as bolted and welded connections, will probably lead to complex designs and higher costs. Therefore, innovative joining technologies are required to be implemented. Snap-fit connections are widely used connecting mechanism for joining plastic components. Due to its simplicity and efficiency while connecting two or more elements together are suitable for different applications. Despite it is not commonly used in the building industry and it is frequently used on small scale applications, the principle based on snap-fit connections could be used to connect the structural members of optimized trusses. First, a literature study provides a clear understanding of truss structures, focusing mainly on the importance of their joints. Structural optimization is also discussed, paying special attention on a new layout-optimization approach, which is based on two steps: first, the less-weight possible layout is obtained (the benchmark) without taking into account any buildable considerations. The second step consists on rationalizing the benchmark contemplating practical and buildable restrictions. Finally, a representative case-study steel truss is presented. The second part of this research explores the structural design and the optimization procedure applied on the case-study truss. Here the layout optimization approach is applied using Peregrine (plugin for Grasshopper). After an optimized layout is generated, it is design structurally using Karamba3D. Finally, the case-study truss and the optimized truss are compared. To explore the opportunity of implementing optimized trusses in practice, the conceptual design of an innovative joint based on snap-fit connections is developed. A representative internal node from the optimized truss is chosen and based on a general concept, three design concepts are created. Extensive Finite Element (FE) analyses are carried out to study the structural behavior of the innovative joint during three main phases. All FE analysis were performed using the FE software Abaqus. To conclude, this research project is an exploratory feasibility study of the use of steel snap-fit joints as internal nodes for optimized steel trusses.

Structural Optimization
Innovative joints
optimized truss
Abaqus
innovative connections
steel structures
Steel Joints
snap-fit

http://resolver.tudelft.nl/uuid:89c7f26e-8190-4f95-bb2c-5f74b2c9b41c

2020-12-10

Student theses

master thesis

© 2020 Jose Antonio Abad Gonzalez