A Review of Generalized Failure Criteria Based on the Plastic Yield Strip Model

Author(s):  
R de Wit
1990 ◽  
Vol 207 ◽  
Author(s):  
T. C. Triantafillou ◽  
L. J. Gibson

AbstractCellular materials are increasingly used in engineering. Proper design requires an understanding of the response of the materials to stress; and, in real engineering design, the stress state is often a complex one. In this paper we model the elastic buckling, plastic yield, and brittle fracture of cellular solids under multiaxial stresses to develop equations describing their failure surfaces. Comparison of the analysis with data shows that the models describe the main features of the multiaxial behavior of foams well.


Author(s):  
JEROME DE SEZE ◽  
Françoise Durand-Dubief ◽  
Elisabeth Maillart ◽  
Elisabeth ['MEKIES'] ◽  
Elisabeth ['papeix'] ◽  
...  

Author(s):  
Luke Jardine ◽  
Kei Lui ◽  
Helen G Liley ◽  
Timothy Schindler ◽  
James Fink ◽  
...  

ObjectiveTo evaluate the safety of an aerosolised surfactant, SF-RI 1, administered via nasal continuous positive airway pressure (nCPAP) and a prototype breath synchronisation device (AeroFact), to preterm infants with respiratory distress syndrome (RDS).DesignMulticentre, open-label, dose-escalation study with historical controls.SettingNewborn intensive care units at Mater Mothers’ Hospital, Brisbane, and Royal Hospital for Women, Sydney, Australia.PatientsInfants 26 weeks through 30 weeks gestation who required nCPAP 6–8 cmH2O and fraction of inspired oxygen (FiO2) <0.30 at <2 hours of age.InterventionsIn part 1, infants received a single dose of 216 mg/kg of aerosolised surfactant. In part 2, infants could receive up to four doses of aerosolised surfactant. Three historical control infants were matched for each enrolled infant.Main outcome measuresTreatment failure was defined as Respiratory Severity Score (FiO2×cmH2O nCPAP) >2.4, nCPAP >8 cmH2O, arterial carbon dioxide >65 mm Hg, pH <7.20 or three severe apnoeas within 6 hours during the first 72 hours of life. Other outcomes included tolerance of the AeroFact treatment and complications of prematurity.Results10 infants were enrolled in part 1 and 21 in part 2 and were compared with 93 historical controls. No safety issues were identified. In part 2, 6 of 21 (29%) AeroFact-treated infants compared with 30 of 63 (48%) control infants met failure criteria. Kaplan-Meier analysis of patients in part 2 showed a trend towards decreased rate of study failure in the AeroFact-treated infants compared with historical controls (p=0.10).ConclusionThe AeroFact system can safely deliver aerosolised surfactant to preterm infants with RDS who are on nCPAP.Trial registration numberACTRN12617001458325.


2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Aleksander Muc

The main goal of building composite materials and structures is to provide appropriate a priori controlled physico-chemical properties. For this purpose, a strengthening is introduced that can bear loads higher than those borne by isotropic materials, improve creep resistance, etc. Composite materials can be designed in a different fashion to meet specific properties requirements.Nevertheless, it is necessary to be careful about the orientation, placement and sizes of different types of reinforcement. These issues should be solved by optimization, which, however, requires the construction of appropriate models. In the present paper we intend to discuss formulations of kinematic and constitutive relations and the possible application of homogenization methods. Then, 2D relations for multilayered composite plates and cylindrical shells are derived with the use of the Euler–Lagrange equations, through the application of the symbolic package Mathematica. The introduced form of the First-Ply-Failure criteria demonstrates the non-uniqueness in solutions and complications in searching for the global macroscopic optimal solutions. The information presented to readers is enriched by adding selected review papers, surveys and monographs in the area of composite structures.


2020 ◽  
Vol 135 ◽  
pp. 105519 ◽  
Author(s):  
Adam Niesłony ◽  
Michał Böhm ◽  
Robert Owsiński

2019 ◽  
Vol 165 ◽  
pp. 102818 ◽  
Author(s):  
Kunpeng Ji ◽  
Bin Liu ◽  
Yongfeng Cheng ◽  
Xueping Zhan ◽  
Ghyslaine McClure

Sign in / Sign up

Export Citation Format

Share Document