Influence of stiffness constraints on optimal design of trusses using morphological indicators

Vandenbergh, Thomas; Ponsaert, Wim; Steirteghem, Jan Van; Wilde, Patrick De; Latteur, Pierre

doi:10.2495/hpsm06004

Cited by 7 publications

(7 citation statements)

References 1 publication

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“…The indicator of displacement allows predicting the maximal static displacement of the structure and can be used to verify if the strength optimised structure does not violate constraints on displacement. When displacements are unacceptable, Vandenbergh et al [26,27] proved that the theory of MI, with sizing based on a fully stressed design, does not necessarily lead to optimal (i.e. lightest) solutions.…”

Section: Benchmarking the Methods By Additional Design Constraintsmentioning

confidence: 99%

Structural optimisation and sustainable design

Wilde¹,

Vandenbergh²,

Debacker³

2015

Int. J. CMEM

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The theory of morphological indicators (MI) provides user-friendly tools guiding the structural designer towards low volume consuming solutions during the exploration and comparison of different structural types. Since a first doctoral thesis published in 1999, a decade of research has refined MI into a benchmarked structural optimisation method for conceptual design. This article surveys the milestones that lead to today's method and contains the published references that contributed to the major evolutions of MI. The article also refers to the work of other researchers in structural and architectural engineering, this time in the quest of optimisation of structures through a more sustainable design, offering the possibility of re-use and recombination of structural components. This technique, called 4D design methodology, was based on a research proposal by Hendrickx and Van Walleghem, which was further developed at Vrije Universiteit Brussel.

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Section: Benchmarking the Methods By Additional Design Constraintsmentioning

confidence: 99%

Structural optimisation and sustainable design

Wilde¹,

Vandenbergh²,

Debacker³

2015

Int. J. CMEM

Self Cite

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“…Initially, the theory on MI only considered design for strength with the volume of used materials as the objective function. This strategy often resulted in a lightweight structure with a questionable lack of stiffness, which implicates a significant increase of material volume in the final design to meet the stiffness criteria [35,36]. Therefore, additional indicators like the indicators of buckling Ψ and displacement ∆ were introduced, improving the results obtained with the volume indicator.…”

Section: Conceptual Design According To Morphological Indicatorsmentioning

confidence: 99%

“…The indicator of volume W allows the designer to compare the necessary material volume for different structures. It is defined as follows: 'The volume of a structure of identical shape with a unity span of 1 m, loaded with a unit force of 1 N with a material of allowable stress of 1 Pa' [35,37]. In its most simple form, only considering design for strength with all elements fully stresses, thus ignoring buckling, the equation for the indicator of volume is: [34].…”

Section: Conceptual Design According To Morphological Indicatorsmentioning

confidence: 99%

Formalising the R of Reduce in a Circular Economy Oriented Design Methodology for Pedestrian and Cycling Bridges

Anastasiades

Lambrechts

Mennes

et al. 2022

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The construction industry consumes over 32% of the annually excavated natural resources worldwide. Additionally, it is responsible for 25% of the annually generated solid waste. To become a more sustainable industry, a circular economy is necessary: resources are kept in use as long as possible, aiming to reduce and recirculate natural resources. In this paper, the investigation focuses on pedestrian truss bridges of the types Warren and Howe. Many pedestrian bridges currently find themselves in their end-of-life phase and most commonly these bridges are demolished and rebuilt, thus needing a lot of new materials and energy. The aim is thus first and foremost to reduce the amount of necessary new materials. For this reason, a design tool will be created, using the software ‘Matlab’, in which truss bridges can be evaluated and compared in the conceptual design stage. The tool is based on the theory of morphological indicators: the volume indicator, displacement indicator, buckling indicator and first natural frequency indicator. These allow a designer to determine the most material efficient Warren or Howe truss bridge design with user-defined constraints concerning deflection, load frequency, buckling and overall dimension. Subsequently, the tool was tested and compared to calculations made in the finite element modelling software Diamonds. In total, 72 steel bridge structures were tested. From these it could be concluded that the manual calculations in Diamonds in general confirmed the results obtained with the automated design tool based on morphological indicators. As such, it allows a designer to converge more quickly towards the best performing structure, thus saving time, materials, and corresponding costs and energy.

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“…As will be shown by Vandenbergh et al [12] in a subsequent paper, the conceptual design of lightweight structures introduces the need for an a priori selection of a design strategy based on the need to satisfy in the first place a SLS or an ULS. This can be achieved through an adequate use of morphological indicators, among which the structural index is also important: it is the only one taking into account the so-called scale effects.…”

Section: Preliminary Conclusionmentioning

confidence: 99%

Conceptual design of lightweight structures: the role of morphological indicators and the structural index

Wilde¹

2006

WIT Transactions on the Built Environment, Vol 85

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Firstly, but in no way exclusively, this paper addresses architectural engineers facing critical design decisions in the phase of so-called "conceptual design". The resulting design must yield a structure showing a sound behaviour in both the serviceability limit state (SLS) and in the ultimate limit state (ULS), also meaning that three essential criteria should be satisfied: strength, stiffness and stability (the latter including, if relevant, an acceptable dynamic behaviour). However, the question very often remains open as to which of the three criteria is overruling the other ones. This paper, a synthesis of the work of a research group headed by the author, tries to show that a conceptual design methodology can be developed, hereby using the concept of morphological indicators (originally developed by P. Samyn, subsequently P. Latteur and within the research group) and a structural index (introduced by Shanley). This methodology also gives an answer to the question that very often arises when designing lightweight structures: "design for strength" or "design for stiffness"? Examples in subsequent papers, presented during this Conference and thus included in these Proceedings, illustrate the methodology nowadays used by our students in

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Influence of stiffness constraints on optimal design of trusses using morphological indicators

Cited by 7 publications

References 1 publication

Structural optimisation and sustainable design

Structural optimisation and sustainable design

Formalising the R of Reduce in a Circular Economy Oriented Design Methodology for Pedestrian and Cycling Bridges

Conceptual design of lightweight structures: the role of morphological indicators and the structural index

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