Shape Optimisation of Cold-Formed Steel Profiles with Manufacturing Constraints - Part I: Algorithm

This paper presents a Genetic Algorithm optimisation method with manufacturing constraints for shape optimisation of cold-formed steel (CFS) profiles. Previous studies on unconstrained shape optimization of CFS crosssections, where the sole aim was to optimise the weight-to-capacity ratio of the profiles, yielded cross-sections that cannot be manufactured. Current coldforming processes, such as roll-forming and brake-pressing, have limited ability to form continuously curved surfaces without discrete bends. This paper defines simple manufacturing rules and introduces them into the evolutionary algorithm. Augmented Lagrangian constraint-handling technique, with equality and inequality constrained violations, is used to avoid ill-conditioned problems. The ability and accuracy of the algorithm to handle the defined manufacturing constraints are verified by implementing it to optimise the section capacity of bisymmetric closed thin-walled profiles, for which an analytical solution is known

Shape Optimisation of Cold-Formed Steel Profiles with Manufacturing Constraints - Part II: Applications

This paper uses the Genetic Algorithm (GA)-based optimisation method for cold-formed steel (CFS) profiles with manufacturing constraints, developed in the companion paper, to shape-optimise simply-supported and singly-symmetric open-section columns. Having a uniform wall thickness of 0.047 inch (1.2 mm), the columns are subjected to a compressive axial load of 16,860 lbf (75kN) and optimised for yielding and global buckling. Column lengths ranging from 3.28 ft (1,000 mm) to 9.84 ft (3,000 mm) are investigated. The algorithm is run with and without considering the manufacturing constraints. Differences between the two types of cross-sections, i.e. manufacturable and non-manufacturable, are evaluated. The influence of the number of manufacturable flat segments on the optimised cross-sectional area is also investigated. Future developments of the method for strength optimisation under combined actions and practical applications are discussed

Shape optimisation of cold-formed steel profiles with manufacturing constraints - Part I: algorithm

This paper presents a Genetic Algorithm optimisation method with manufacturing constraints for shape optimisation of cold-formed steel (CFS) profiles. Previous studies on unconstrained shape optimisation of CFS cross- sections, where the sole aim was to optimise the weight-to-capacity ratio of the profiles, yielded cross-sections that cannot be manufactured. Current cold- forming processes, such as roll-forming and brake-pressing, have limited ability to form continuously curved surfaces without discrete bends. This paper defines simple manufacturing rules and introduces them into the evolutionary algorithm. Augmented Lagrangian constraint-handling technique, with equality and inequality constrained violations, is used to avoid ill-conditioned problems. The ability and accuracy of the algorithm to handle the defined manufacturing constraints are verified by implementing it to optimise the section capacity of bisymmetric closed thin-walled profiles, for which an analytical solution is known

Successful Thrombectomy Improves Functional Outcome in Tandem Occlusions with a Large Ischemic Core

International audienceBackground: Emergent stenting in tandem occlusions and mechanical thrombectomy (MT) of acute ischemic stroke related to large vessel occlusion (LVO-AIS) with a large core are tested independently. We aim to assess the impact of reperfusion with MT in patients with LVO-AIS with a large core and a tandem occlusion and to compare the safety of reperfusion between large core with tandem and nontandem occlusions in current practice. Methods: We analyzed data of all consecutive patients included in the prospective Endovascular Treatment in Ischemic Stroke Registry in France between January 2015 and March 2023 who presented with a pretreatment ASPECTS (Alberta Stroke Program Early CT Score) of 0–5 and angiographically proven tandem occlusion. The primary end point was a favorable outcome defined by a modified Rankin Scale (mRS) score of 0–3 at 90 days. Results: Among 262 included patients with a tandem occlusion and ASPECTS 0–5, 203 patients (77.5%) had a successful reperfusion (modified Thrombolysis in Cerebral Infarction grade 2b-3). Reperfused patients had a favorable shift in the overall mRS score distribution (adjusted odds ratio [aOR], 1.57 [1.22–2.03]; P < 0.001), higher rates of mRS score 0–3 (aOR, 7.03 [2.60–19.01]; P < 0.001) and mRS score 0–2 at 90 days (aOR, 3.85 [1.39–10.68]; P = 0.009) compared with nonreperfused. There was a trend between the occurrence of successful reperfusion and a decreased rate of symptomatic intracranial hemorrhage (aOR, 0.5 [0.22–1.13]; P = 0.096). Similar safety outcomes were observed after large core reperfusion in tandem and nontandem occlusions. Conclusions: Successful reperfusion was associated with a higher rate of favorable outcome in large core LVO-AIS with a tandem occlusion, with a safety profile similar to nontandem occlusion