Geometrically nonlinear simulation of textile membrane structures based on orthotropic hyperelastic energy functions

2019 ◽  
Vol 223 ◽  
pp. 110908 ◽  
Author(s):  
Mehran Motevalli ◽  
Jörg Uhlemann ◽  
Natalie Stranghöner ◽  
Daniel Balzani
Keyword(s):  
Geometrically Nonlinear ◽  
Membrane Structures ◽  
Energy Functions ◽  
Nonlinear Simulation

scholarly journals Orthotropic Hyperelastic Energy Functions for the Geometrically Nonlinear Simulation of Textile Membrane Structures

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mehran Motevalli ◽  
Daniel Balzani ◽  
Jörg Uhlemann ◽  
Natalie Stranghöner
Keyword(s):  
Geometrically Nonlinear ◽  
Membrane Structures ◽  
Energy Functions ◽  
Nonlinear Simulation

scholarly journals A nondestructive method for the pretension detection in membrane structures based on nonlinear vibration response to impact

2017 ◽  
Vol 17 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Chang-Jiang Liu ◽  
Michael D Todd ◽  
Zhou-Lian Zheng ◽  
Yu-You Wu
Keyword(s):  
Nonlinear Vibration ◽  
Membrane Surface ◽  
Nondestructive Method ◽  
Geometrically Nonlinear ◽  
Membrane Structures ◽  
Low Velocity ◽  
Theoretical Idea ◽  
Theoretical Derivation ◽  
Geometrically Nonlinear Vibration ◽  
External Loads

The pretension of building membrane structures may relax over its service lifetime, which may cause engineering failure under external loads. Therefore, the pretension of building membrane structures should be monitored or estimated regularly to compare the actual pretension to its design pretension and then to adopt some strengthening measures to mitigate future problems. Based on the geometrically nonlinear vibration of a rectangular orthotropic membrane structure, a nondestructive detection method for monitoring its pretension is developed in this article. This method is achieved by impacting a low-velocity pellet onto the membrane surface to generate vibration and detecting its response amplitude. Then the detected amplitude is converted into a pretension estimate via a derived formula. In addition, experiments for three kinds of conventional membrane material (Heytex H5573, Xing Yi Da, and ZZF 3010) were carried out according to the theoretical idea. The experimental results proved this method is feasible and verified the theoretical derivation is reasonable.

Unequivocally Nonconservative Results From One Method of Imperfection Quantification in RCC-MR

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Ashok Kumar ◽  
Anindya Chatterjee
Keyword(s):  
External Pressure ◽  
Thin Shells ◽  
Geometrically Nonlinear ◽  
Nonlinear Simulation ◽  
The Third ◽  
Quantification Method ◽  
Post Buckling ◽  
Specific Shape ◽  
Large Material ◽  
Safe Load

Abstract Design against buckling of thin shells at high temperatures often follows the code RCC-MR. RCC-MR allows three methods to quantify shell imperfections for use in safe load calculations, where lower imperfection values raise the safe load estimates. In recent work, we showed that the third of these methods can sometimes yield remarkably low imperfection values, leading to potentially nonconservative designs, but nonconservatism of the method was not proved. Here, we prove nonconservatism in two designs based on the third method. Proving such nonconservatism is difficult using experiments or with large material nonlinearity in simulations. We first discuss these difficulties to motivate our approach. We then present two examples: a spherical shell and a torispherical shell, both under external pressure. The shell walls are thin enough so that plasticity is not encountered before structural collapse. For specific shape imperfections, we show with geometrically nonlinear, purely elastic, highly refined, post-buckling analysis using abaqus that the physical loads at which the imperfect shells collapse are overpredicted via RCC-MR's third method by factors of about 8/7 and 11/10, respectively. We emphasize that code-based design using nonlinear simulation prescribes a further safety factor of 2.5, which we have denied ourselves here in order to give the third method the benefit of doubt. We conclude that the third imperfection quantification method in RCC-MR should be reexamined.

Geometrically Nonlinear Response of Beam and Membrane Structures by Exact Reduction Technique

1998 ◽  
Author(s):  
Cho W. S. To ◽  
Lingchuan Li
Keyword(s):  
Finite Element ◽  
Nonlinear Response ◽  
Large Scale ◽  
Computational Cost ◽  
Free Vibration Analysis ◽  
Structural Systems ◽  
Second Phase ◽  
Geometrically Nonlinear ◽  
Theoretic Approach ◽  
Membrane Structures

Abstract Large scale dynamic finite element analysis of complex nonlinear mechanical or structural systems can be very expensive. To significantly reduce the computational cost various techniques have been developed and presented in the literature. The reduction method based on symmetry group or the so-called group theoretic approach (GTA) of Healey and associates for bifurcation analysis and free vibration analysis of geometrically nonlinear systems with symmetries has been extended by the authors to deal with transient geometrically nonlinear response of structures discretized by the finite element method (FEM). Computed results for two discretized space trusses were obtained with the GTA, and presented by the authors in a previous paper. Application is further made of the GTA for the computation of geometrically nonlinear response of beam and membrane structures during the second phase of the investigation reported here. The obtained numerical results indicate that the GTA can be applied to relatively more complicated structural systems that include symmetry of nodal rotations. It was observed that the results obtained by the GTA are very accurate and the GTA is very efficient compared with technique for the full space problems.

Ultrastructural Changes of the Tissue Thromboplastin after Intravenous Injection in Rabbits

1978 ◽  
Vol 39 (01) ◽  
pp. 201-209 ◽  
Author(s):  
Hiroshi Hasegawa ◽  
Hiroshi Nagata ◽  
Makoto Murao
Keyword(s):  
Intravenous Injection ◽  
Vascular Endothelium ◽  
Model Experiment ◽  
Venous Return ◽  
Ultrastructural Changes ◽  
Membrane Structures ◽  
Tissue Thromboplastin ◽  
Short Time ◽  
Sheet Membrane

SummaryAttempts were made to demonstrate ultrastructural changes of the tissue thromboplastin after intravenous injection, as a model experiment on the pulmonary microthrombi formation induced by the tissue thromboplastin circulating from venous return.Concentrically arranged membrane structures of the injected thromboplastin disappeared in extremely short time after the injection of the thromboplastin in rabbits. The long sheet membrane of the injected thromboplastin was frequently seen as adhered to the vascular endothelium or to the surface of blood corpuscles. Furthermore, fibrin fibres were formed in contact with the long sheet membrane of the thromboplastin. Membrane structures were not found anywhere in the control rabbits.

Ultramicroscopic and Coagulation-Fibrinolytic Findings Induced by Tissue Thromboplastin

1979 ◽  
Author(s):  
H Nagata ◽  
T Seya ◽  
Y Oguma ◽  
M Yamauchi ◽  
T Murakoshi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Hypercoagulable State ◽  
Membrane Structures ◽  
Transmission Electron ◽  
Single Sheet ◽  
Tissue Thromboplastin ◽  
Short Time

We have studied the ultrastructures of tissue thromboplastin (T.Tbp) to demonstrate how It changes during coagulation.[Materials and Methods] T.Tbp from lungs of rabbits was used for these studies. It was injected into ear veins of rabbits. Lungs were resected at several seconds, 10sec, 1 min, 5 min, 24 hrs or 48 hrs after the injection. They were examined by transmission electron microscope.[Results] Concentrically arranged membrane structures of the injected T.Tbp disappeared in extremely short time after the injection. 1 min after the injection, fibrin fibers were seen between single sheet of membrane and endothelial cells of capillaries. In the rabbit which had died suddenly after the injection of T.Tbp, multiple pulmonary thrombi made of fibrin and platelets were seen in capillaries. The endothelial cells of capillaries were destroyed and interstitial tissues were edematous.The hypercoagulable state was seen 10~30sec after the start of the injection, indicating the shortening of r of TEG. Then, it gradually returned the level before injection. Moreover, changes of the measurements of fibrinogen, antiplasmin and prekallikrein were also seen after the injection.

NONLINEAR SIMULATION OF A HIGH-SPEED, VISCOUS LIQUID JET

1998 ◽  
Vol 8 (2) ◽  
pp. 155-178 ◽  
Author(s):  
J. H. Hilbing ◽  
Stephen D. Heister
Keyword(s):  
Viscous Liquid ◽  
High Speed ◽  
Liquid Jet ◽  
Nonlinear Simulation

Static Geometrically Nonlinear Aeroelastic Framework for Multi-Fidelity Analysis

2020 ◽  
Vol 68 (4) ◽  
pp. 142-147
Author(s):  
Natsuki Tsushima ◽  
Masato Tamayama ◽  
Tomohiro Yokozeki
Keyword(s):  
Geometrically Nonlinear
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