Analysis of multiple stiffened barrel shell structures by strain-based finite elements

In this paper strain-based rectangular cylindrical shell and curved arch finite elements are coupled to straight beam finite elements to analyse multiple stiffened barrel shell structures. The first two finite elements are based on assumed strains rather than displacement fields. The results obtained with this analysis are successfully compared with values derived from several commercial computer codes. (C) 1999 Elsevier Science Ltd. All rights reserved.35423325

ANALYSIS OF CRACKED CYLINDRICAL-SHELLS BY A STRAIN-BASED FINITE-ELEMENT

In this paper, parameters necessary to implement the Strip Yield Zone Model (Dugdale, D.S., J. Mech. Phys. Solids 1960 8, 100-4)a in the analysis of pressurized cylindrical shells are evaluated using a strain-based finite element. The shell finite element employed is a strain-based bidimensional cylindrical circular element with four nodes and five degrees of freedom for each node. Two types of crack orientation are considered: axial and circumferential, and results are presented relating the ratios of remote stress/yield stress and the opening displacements to the ratios of yield zone length/crack length.171394

2019 European League Against Rheumatism/American College of Rheumatology classification criteria for systemic lupus erythematosus

Objective: To develop new classification criteria for systemic lupus erythematosus (SLE) jointly supported by the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR). Methods: This international initiative had four phases. (1) Evaluation of antinuclear antibody (ANA) as an entry criterion through systematic review and meta-regression of the literature and criteria generation through an international Delphi exercise, an early patient cohort and a patient survey. (2) Criteria reduction by Delphi and nominal group technique exercises. (3) Criteria definition and weighting based on criterion performance and on results of a multi-criteria decision analysis. (4) Refinement of weights and threshold scores in a new derivation cohort of 1001 subjects and validation compared with previous criteria in a new validation cohort of 1270 subjects. Results: The 2019 EULAR/ACR classification criteria for SLE include positive ANA at least once as obligatory entry criterion; followed by additive weighted criteria grouped in seven clinical (constitutional, haematological, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal) and three immunological (antiphospholipid antibodies, complement proteins, SLE-specific antibodies) domains, and weighted from 2 to 10. Patients accumulating ≥10 points are classified. In the validation cohort, the new criteria had a sensitivity of 96.1% and specificity of 93.4%, compared with 82.8% sensitivity and 93.4% specificity of the ACR 1997 and 96.7% sensitivity and 83.7% specificity of the Systemic Lupus International Collaborating Clinics 2012 criteria. Conclusion: These new classification criteria were developed using rigorous methodology with multidisciplinary and international input, and have excellent sensitivity and specificity. Use of ANA entry criterion, hierarchically clustered and weighted criteria reflect current thinking about SLE and provide an improved foundation for SLE research