Cold-formed steel channel columns optimization with simulated annealing method

Moacir Kripka,Zacarias Martin Chamberlain Pravia 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.3

Cold-formed profiles have been largely used in the building industry because they can be easily produced and because they allow for a wide range of sections and thus can be utilized to meet different project requirements. Attainment of maximum performance by structural elements with low use of material is a challenge for engineering projects. This paper presents a numerical study aimed at minimizing the weight of lipped and unlipped cold-formed channel columns, following the AISI 2007 specification. Flexural, torsional and torsional–flexural buckling of columns was considered as constraints. The simulated annealing method was used for optimization. Several numerical simulations are presented and discussed to validate the proposal, in addition to an experimental example that qualifies its implementation. The ratios between lips, web width, and flange width are analyzed. Finally, it may be concluded that the optimization process yields excellent results in terms of cross-sectional area reduction.

Cold-formed steel channel columns optimization with simulated annealing method

Kripka, Moacir,Chamberlain Pravia, Zacarias Martin Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.3

Cold-formed profiles have been largely used in the building industry because they can be easily produced and because they allow for a wide range of sections and thus can be utilized to meet different project requirements. Attainment of maximum performance by structural elements with low use of material is a challenge for engineering projects. This paper presents a numerical study aimed at minimizing the weight of lipped and unlipped cold-formed channel columns, following the AISI 2007 specification. Flexural, torsional and torsional-flexural buckling of columns was considered as constraints. The simulated annealing method was used for optimization. Several numerical simulations are presented and discussed to validate the proposal, in addition to an experimental example that qualifies its implementation. The ratios between lips, web width, and flange width are analyzed. Finally, it may be concluded that the optimization process yields excellent results in terms of cross-sectional area reduction.

Optimization of steel-concrete composite beams considering cost and environmental impact

Andréia Fátima Tormen,Zacarias Martin Chamberlain Pravia,Fernando Busato Ramires,Moacir Kripka 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.3

In the optimized structure sizing, the optimization methods are inserted in this context in order to obtain satisfactory solutions, which can provide more economical structures, besides allowing the consideration of the factors related to the environmental impacts in the structural design. This work proposes a mathematical model for the optimization of steel-concrete composite beams aiming to minimize the monetary cost and the environmental impact, using the Harmonic Search optimization method. Discrete variables were the dimensions of the steel profiles and the thickness of the collaborating slab of the composite steel-concrete beam. The proposed model was implemented in Fortran programming language and based on improvements in the structure of the optimization method proposed by Medeiros and Kripka (2017). To prove the effectiveness and applicability of the model, as well as the Harmonic Search method, analyzes were performed with different configurations of steel-concrete composite beams, in order to provide guidelines that make the use of these systems more streamlined. In general, the Harmonic Search optimization method has proved to be efficient in the search for the optimized solutions, as well as important considerations on the optimization of the monetary and environmental costs of steel-concrete composite beams were obtained from the developed examples.

Discrete sizing and layout optimization of steel truss-framed structures with Simulated Annealing Algorithm

Jéssica M. Bresolin,Zacarias M.C. Pravia,Moacir Kripka 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.5

Structural design, in general, is developed through trial and error technique which is guided by standards criteria and based on the intuition and experience of the engineer, a context that leads to structural over-dimensioning, with uneconomic solutions. Aiming to find the optimal design, structural optimization methods have been developed to find a balance between cost, structural safety, and material performance. These methods have become a great opportunity in the steel structural engineering domain since they have as their main purpose is weight minimization, a factor directly correlated to the real cost of the structure. Assuming an objective function of minimum weight with stress and displacement constraints provided by Brazilian standards, the present research proposes the sizing optimization and combined approach of sizing and shape optimization, through a software developed to implement the Simulated Annealing metaheuristic algorithm. Therefore, two steel plane frame layouts, each admitting four typical truss geometries, were proposed in order to expose the difference between the optimal solutions. The assessment of the optimal solutions indicates a notable weight reduction, especially in sizing and shape optimization combination, in which the quantity of design variables is increased along with the search space, improving the efficiency of the optimal solutions achieved.

Existence of Solutions for a Class of p(x)-Kirchhoff Type Equation with Dependence on the Gradient

Lapa, Eugenio Cabanillas,Barros, Juan Benito Bernui,de la Cruz Marcacuzco, Rocio Julieta,Segura, Zacarias Huaringa Department of Mathematics 2018 Kyungpook mathematical journal Vol.58 No.3

The object of this work is to study the existence of solutions for a class of p(x)-Kirchhoff type problem under no-flux boundary conditions with dependence on the gradient. We establish our results by using the degree theory for operators of ($S_+$) type in the framework of variable exponent Sobolev spaces.

Poster Session:PS 0198 ; Endocrinology : Giant Cystic Prolactinoma in a Woman: Do Not Forget the Hook Effect

( Rene Rodriguez Gutierrez ),( Karla V Rodriguez Velver ),( Maria Azucena Zapata Rivera ),( Roberto Monreal Robles ),( Fernando J Lavalle Gonzalez ),( Jose G Gonzalez Gonzalezz ),( Jesus Zacarias Vill 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background and Case Presentation: Cystic prolactinomas correspond to = 1% of all prolactinomas and its association with a giant pituitary macroadenoma in a woman has been seldom reported. A 43-year old woman was evaluated for a suprasellar tumor. She had absence of menses since 2 years. Three months before she started to have progressive headache. She also referred asthenia, adynamia, fatigue, dry hairiness, decreased libido, vaginal atrophy, and chronic constipation. Hair in armpits and pubic area was insignificant and osteotendinous reflex relaxation phase was slow. Galactorrhea was absent and presented bitemporal hemianopsia. Diagnostic and Therapeutic Approach: MRI scan revealed a 5 x 3.5 cm suprasellar mass and a 8.1 x 3.6 cm cystic component (Figures 1-3). Cortisol level 2.2 mg/dl, FSH and LH were low, estradiol < 0.05 pg/mL, IGF-1 normal and a serum prolactin of 125 ng/mL. Serial dilutions 1:10 and 1:100 were made. Diluted prolactine was 12,500 ng/mL (hook effect). Treatment with cabergoline, prednisone and levothyroxine were initiated. At two months follow-up prolactin serum levels decreased to 32.1 ng/mL. Discussion and Conclusion: A systemic research on PubMed, Medline, Embase and MedConsult with the search criteria: “Giant Cystic Prolactinoma”, “prolactin”, “prolactioma and “hook effect” was made. Due to the clinical signs of hypogonadism, the image in the MRI and the low/moderate high serum prolactin levels serial dilutions of prolactin were made. Serum prolactin assays can greatly underestimate extremely high levels of hormone, the so called “hook effect”. In present case, a high level of suspicion along with low/moderate prolactin levels and the MRI image consistent with a pituitary adenoma made us ask for diluted prolactin samples. If missed, this would have delayed the diagnosis and consequently would have changed the treatment plan and prognosis of the patient.

Poster Session:PS 0197 ; Endocrinology : Severe Hypercalcemia: Chronic Tophaceous Gout the Responsible Cause?

( Rene Rodriguez Gutierrez ),( Roberto Monreal Robles ),( Maria Azucena Zapata Rivera ),( Karla V Rodriguez Velver ),( Fernando Jj Lavallegonzalez ),( Jose Gerardo Gonzalez Gonzalez ),( Jesus Zacarias 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background and Description: The association of chronic tophaceous gout with severe hypercalcemia is extremely rare and has been usually associated with calcitriol secretion. PTHrP has never been described as the responsible cause. A 42-year old man with a long stand history of chronic gout initiated a week before admission with polyuria, polypsia and progressive altered mental status. Neurological examination revealed only lethargy. Characteristic, multiple, non-tender tophi were obvious at inspection (Figures 1-3). Initial laboratory work up revealed a uric acid of 14.0 mg/dl, calcium of 14.5 mg/dl, phosphorous of 6.3 mg/dl, creatinine of 5.4 mg/dl, blood nitrogen urea of 56, a MDRD GFR of 16 ml/min. Diagnostic and Therapeutic Approach: PTH was suppressed (< 3.0 pg/ml), 25-dihydroxyvitamin D was normal, PTHrP was elevated 45.0 pg/ml, and calcitriol normal (19.6 pg/ml). Radiographs revealed bone erosions (Figure 1-3). Bone scan and a PET-CT were negative for metastasis and malignancy. Treatment was initiated with calcitonin, hydration and prednisone. PTH, 25-dihydroxyvitamin D, PTHrP, and calcitriol returned to normal values. At 6 months follow-up he referred no pain, tophi had improved and calcium levels were within normal range. Discussion and Conclusion: A systemic research on PubMed, Medline, Embase and MedConsult with the search criteria: “Tophaceous gout”, hypercalcemia”, “calcitriol”, “PTHrP”, was made. The proposed mechanism has being an enhanced 1a-hydroxylation of vitamin D in a proliferative chronic synovitis. In this case calcitriol levels were normal. PTHrP had never been, until now, described as the responsible cause of hypercalcemia in gout. In our case baseline PTHrP and calcium values were elevated and after medical treatment both returned to normal values. Immobilization is another well-known cause of mild calcium elevations. It is likely that in this case this was an exacerbating rather than the primary factor.