scholarly journals An Applicability of Vyalov’s equations to ice wall strength estimation

2020 ◽  
Vol 14 (53) ◽  
pp. 394-405
Author(s):  
Anastasiya Kostina ◽  
Maxim Zelnin ◽  
Oleg Plekhov ◽  
Ivan Panteleev ◽  
Lev Levin ◽  
...  
Keyword(s):  
Wall Strength

scholarly journals Axial compression behavior of concrete masonry wallettes strengthened with cement mortar overlays

2008 ◽  
Vol 1 (2) ◽  
pp. 158-170 ◽  
Author(s):  
F. L. De Oliveira ◽  
J. B. De Hanai
Keyword(s):  
Axial Compression ◽  
Cement Mortar ◽  
High Strength ◽  
Concrete Block ◽  
Masonry Wall ◽  
Compression Tests ◽  
Steel Mesh ◽  
Mortar Strength ◽  
Theoretical Approaches ◽  
Wall Strength

This paper presents the results of a series of axial compression tests on concrete block wallettes coated with cement mortar overlays. Different types of mortars and combinations with steel welded meshes and fibers were tested. The experimental results were discussed based on different theoretical approaches: analytical and Finite Element Method models. The main conclusions are: a) the application of mortar overlays increases the wall strength, but not in a uniform manner; b) the strengthening efficiency of wallettes loaded in axial compression is not proportional to the overlay mortar strength because it can be affected by the failure mechanisms of the wall; c) steel mesh reinforced overlays in combination with high strength mortar show better efficiency, because the steel mesh mitigates the damage effects in the block wall and in the overlays themselves; d) simplified theoretical methods of analysis as described in this paper can give satisfactory predictions of masonry wall behavior up to a certain level.

Passive Safety Analysis for the Commercial Vehicle Cab after Weight-Reduction Design

2015 ◽  
Vol 798 ◽  
pp. 48-52 ◽  
Author(s):  
Jing Chen ◽  
Hong Yin Wang ◽  
Qian Wang ◽  
Xiong Long Tao
Keyword(s):  
Weight Reduction ◽  
Strength Test ◽  
Commercial Vehicles ◽  
Finite Element Program ◽  
Explicit Finite Element ◽  
Wall Strength ◽  
Element Program ◽  
Roof Strength ◽  
Front Impact ◽  
Crash Tests

Lighter weight commercial vehicles facilitate faster transport, higher mobility and fuel conservation. Weight reduction and safety are mutually competing objectives. And the safety should not be compromised after weight reduction. Full size crash tests are expensive and time consuming to organize. Using a numerical simulation for predicting crash to the occupants’ safety can minimize the number of such trials. In this paper three virtual crash simulations for the three load cases: Front impact test, Roof strength test and Rear wall strength test are performed according to the European regulation ECE-R29. The explicit finite element program LS-DYNA is used for that purpose. The comparisons between simulation results and test data available in the literature are also presented in this paper.

Computerized Model of Transition in Circular Pipe Flows: Part 2 — Calculation of the Minimum Critical Reynolds Number

1999 ◽  
Author(s):  
Hidesada Kanda
Keyword(s):  
Reynolds Number ◽  
Critical Reynolds Number ◽  
Radial Component ◽  
Entrance Region ◽  
Wall Strength ◽  
Normal Wall ◽  
Acceleration Force ◽  
Profile Changes ◽  
Grid Points ◽  
Pipe Inlet

Abstract From the conclusions of the previous paper, Part 1, it is clear that the transition occurs in the entrance region and the critical Reynolds number takes the minimum value of about 2000 for the case of a straight pipe. In the entrance region, the velocity profile changes from a uniform distribution at the pipe inlet to a parabolic one at the entrance length. Kanda and Oshima (1998b) found that in the entrance region, the radial component of the curl of vorticity multiplied by (2/Re), which we call the normal wall strength, works as an acceleration force together with the continuity equation, and that the normal wall strength decreases inversely as the Reynolds number increases. Hence, the onset of the transition should depend on whether or not the acceleration power provided by the normal wall strength exceeds a required value. In this study the author calculated the acceleration power via finite difference calculations, and thus obtained the minimum critical Reynolds number of 2040 when using J0 = 101 grid points, and 2630 when using J0 = 51.

scholarly journals Modelling of confined masonry structure and its application for the design of multi-story building

2019 ◽  
Vol 276 ◽  
pp. 01034
Author(s):  
Made Sukrawa ◽  
Gede Pringgana ◽  
Putu Ayu Ratih Yustinaputri
Keyword(s):  
Maximum Stress ◽  
Residential Building ◽  
Shell Element ◽  
Reinforced Concrete Beams ◽  
Seismic Load ◽  
Confined Masonry ◽  
Shell Elements ◽  
Wall Strength ◽  
Story Building ◽  
Better Than

The confined masonry (CM) structure has been commonly used in the construction of one-story buildings in Indonesia. Its application for multi-story buildings however, is not yet as popular as the alternative options. This research numerically investigated the behavior of confined masonry and its application for use as the main structure of multi-story buildings subjected to seismic loading. From the validation models it was revealed that, using shell element for masonry walls, reinforced concrete beams and tie-columns, the CM model mimic the load deformation curve of tested specimen better than that using frame and shell elements. The application of the modeling technique for the design of 3-story residential building using wall density index less than that suggested in the literature resulted in a safe and stiff structure. The wall stresses under design seismic load were still less than the wall strength and the drift ratio of the model was 0.06% much smaller than the limit of 0.2%. The maximum stress observed at the corners of wall opening justify the need for confinement along the opening.

scholarly journals Ethanol and H2O2 stresses enhance lipid production in an oleaginous Rhodotorula toruloides thermotolerant mutant L1-1

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Chih-Chan Wu ◽  
Takao Ohashi ◽  
Ryo Misaki ◽  
Savitree Limtong ◽  
Kazuhito Fujiyama
Keyword(s):  
Stress Tolerance ◽  
Membrane Lipids ◽  
Lipid Production ◽  
Industrial Applications ◽  
Stress Conditions ◽  
Lipid Productivity ◽  
Ethanol Stress ◽  
Wall Strength ◽  
Thermotolerant Strain ◽  
A Cell

Abstract Stress tolerance is a desired characteristic of yeast strains for industrial applications. Stress tolerance has been well described in Saccharomyces yeasts but has not yet been characterized in oleaginous Rhodotorula yeasts even though they are considered promising platforms for lipid production owing to their outstanding lipogenicity. In a previous study, the thermotolerant strain L1–1 was isolated from R. toruloides DMKU3-TK16 (formerly Rhodosporidium toruloides). In this study, we aimed to further examine the ability of this strain to tolerate other stresses and its lipid productivity under various stress conditions. We found that the L1–1 strain could tolerate not only thermal stress but also oxidative stress (ethanol and H2O2), osmotic stress (glucose) and a cell membrane disturbing reagent (DMSO). Our results also showed that the L1–1 strain exhibited enhanced ability to maintain ROS homeostasis, stronger cell wall strength and increased levels of unsaturated membrane lipids under various stresses. Moreover, we also demonstrated that ethanol-induced stress significantly increased the lipid productivity of the thermotolerant L1–1. The thermotolerant L1–1 was also found to produce a higher lipid titer under the dual ethanol-H2O2 stress than under non-stress conditions. This is the first report to indicate that ethanol stress can induce lipid production in an R. toruloides thermotolerant strain.

The Damage Tolerance of a Sandwich Panel Containing a Cracked Honeycomb Core

2009 ◽  
Vol 76 (6) ◽  
Author(s):  
I. Quintana Alonso ◽  
N. A. Fleck
Keyword(s):  
Finite Element ◽  
Sandwich Panel ◽  
Finite Element Simulations ◽  
Analytical Models ◽  
Tensile Fracture ◽  
Linear Elastic ◽  
Statistical Variation ◽  
Wall Strength ◽  
Elastic Fracture ◽  
Weibull Theory

The tensile fracture strength of a sandwich panel, with a center-cracked core made from an elastic-brittle diamond-celled honeycomb, is explored by analytical models and finite element simulations. The crack is on the midplane of the core and loading is normal to the faces of the sandwich panel. Both the analytical models and finite element simulations indicate that linear elastic fracture mechanics applies when a K-field exists on a scale larger than the cell size. However, there is a regime of geometries for which no K-field exists; in this regime, the stress concentration at the crack tip is negligible and the net strength of the cracked specimen is comparable to the unnotched strength. A fracture map is developed for the sandwich panel with axes given by the sandwich geometry. The effect of a statistical variation in the cell-wall strength is explored using Weibull theory, and the consequences of a stochastic strength upon the fracture map are outlined.

Abdominal Aortic Aneurysm Growth: The Association of Aortic Wall Mechanics and Geometry

2011 ◽  
Author(s):  
Christopher B. Washington ◽  
Judy Shum ◽  
Satish C. Muluk ◽  
Ender A. Finol
Keyword(s):  
Wall Stress ◽  
Abdominal Ultrasound ◽  
Aneurysm Rupture ◽  
Computational Method ◽  
Maximum Diameter ◽  
Patient Specific ◽  
Element Analysis ◽  
Wall Strength ◽  
Aneurysm Growth ◽  
Peak Wall Stress

In an effort to prevent rupture, patients with known AAA undergo periodic abdominal ultrasound or CT scan surveillance. When the aneurysm grows to a diameter of 5.0–5.5 cm or is shown to expand at a rate greater than 1 cm/yr, elective operative repair is undertaken. While this strategy certainly prevents a number of potentially catastrophic ruptures, AAA rupture can occur at sizes less than 5 cm. From a biomechanical standpoint, aneurysm rupture occurs when wall stress exceeds wall strength. By using non-invasive techniques, such as finite element analysis (FEA), wall stress can be estimated for patient specific AAA models, which can perhaps more carefully predict the rupture potential of a given aneurysm, regardless of size. FEA is a computational method that can be used to evaluate complicated structures such as aneurysms. To this end, it was reported earlier that AAA peak wall stress provides a better assessment of rupture risk than the commonly used maximum diameter criterion [1]. What has yet to be examined, however, is the relationship between wall stress and AAA geometry during aneurysm growth. Such finding has the potential for providing individualized predictions of AAA rupture potential during patient surveillance. The purpose of this study is to estimate peak wall stress for an AAA under surveillance and evaluate its potential correlation with geometric features characteristic of the aneurysm’s morphology.

Ascending Thoracic Aorta Exhibits Anisotropic Failure Behavior in Shear Lap Testing

2013 ◽  
Author(s):  
Colleen Witzenburg ◽  
Sachin Shah ◽  
Hallie P. Wagner ◽  
Janna Goodrich ◽  
Victor H. Barocas
Keyword(s):  
Arterial Pressure ◽  
Mechanical Behavior ◽  
Thoracic Aorta ◽  
Ascending Aorta ◽  
Aortic Aneurysms ◽  
Failure Behavior ◽  
Thoracic Aortic Aneurysms ◽  
Wall Strength ◽  
Imminent Death ◽  
Aneurysm Dissection

Aneurysm dissection and rupture, resulting in imminent death, is the primary risk associated with thoracic aortic aneurysms (TAA). Nearly 60% of TAA involves the ascending aorta [1]. Dissection and rupture occur when the remodeled tissue is no longer able to withstand the stresses generated by the arterial pressure. As the ascending TAA grows, however, changes in its mechanical behavior, particularly wall strength, are unknown.

scholarly journals RESPON SEISMIK STRUKTUR RANGKA DINDING PENGISI YANG DIMODEL DENGAN ELEMEN SHELL PENUH DAN PARSIAL

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Putu Ratna Suryantini ◽  
M. Sukrawa ◽  
I. A. M Budiwati
Keyword(s):  
Shell Model ◽  
3D Structure ◽  
Shell Element ◽  
Maximum Load ◽  
3D Models ◽  
Frame Structure ◽  
Natural Period ◽  
Shell Elements ◽  
Frame Model ◽  
Wall Strength

Abstract: Research on the seismic response of in-filled frame structure has been done with in-filled frame model as full and partial shell elements. The wall is considered active until the maximum load on the full shell models, while the partial shell model using the gradual load with the strength of the wall is considered inactive if the stress of the wall exceeded the wall strength The 4 storey hotel building with full wall in x-direction and wall with opening in y-direction were modeled in SAP 2000 as 3D infilled-frame using full and partial shell element. In Mxy models, both wall were included in the model, while in My models, only the wall in y-direction included. Therefore, 4 models were obtained, there are full shell model MxyShPn and MyShPn and partial shell model MyShPar and MyShPar. In addition, 2 diagonal strut models MxyS and MyS  and an open frame model MOF were made as comparison. Prior to model 3D structure, validation models were created using test result condited by other as reference. For that purphose 5 2D models were created there are open frame model MOF, single strut model MST, multiple strut model MSG, full shell model MShPn and  partial shell model MShPar. From validation models, it is apparent that the MxyShPar model mimic the behavior of tested structure better than the other models. From the 3D models analysis result show that the displacement in x-direction of MxyShPn, MxyShPar, MxyS were 89%, 85%, 84% smaller than those of MOF, respectively inclusion of wall in the models, also reduce the internal forces and reduse the natural period of the sctructure.

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