Predicting Damping of a Cantilever Beam With a Bolted Joint Using Quasi-Static Modal Analysis

2017 ◽  
Author(s):  
Emily A. Jewell ◽  
Matthew S. Allen ◽  
Robert Lacayo
Keyword(s):  
Modal Analysis ◽  
Three Dimensional ◽  
Lessons Learned ◽  
Effective Stiffness ◽  
Bolt Preload ◽  
Mesh Density ◽  
Three Dimensional Models ◽  
Nonlinear Modal Analysis ◽  
Stiffness And Damping ◽  
2D And 3D

Bolted joints are common in assembled structures and are a large contributor to the damping in these assemblies. The joints can cause the structure to behave nonlinearly, and introduce uncertainty because the effective stiffness and damping at the joint are typically unknown. Consequently, improved modeling methods are desired that will address the nonlinearity of the jointed structured while also providing reasonable predictions of the effective stiffness and damping of the joint as a function of loading. A method proposed by Festjens, Chevallier and Dion addresses this by using a sort of nonlinear modal analysis based on the response of the structure to quasi-static loading. This was further developed by Allen and Lacayo and thoroughly demonstrated for structures with discrete Iwan joints. This work explores the efficacy of quasi-static modal analysis for 2D and 3D finite element models in which the geometry, contact pressure and friction in the joint are modeled in detail. The mesh density, contact laws, and other solver settings are explored to understand what is needed to obtain convergence for this type of problem. For the 2D case study, the effect of bolt preload and coefficient of friction are explored and shown to produce reasonable trends. Three dimensional models prove far more challenging and significant effort was required to obtain convergence and then to obtain results that are physically realistic; these efforts are reported as well as the lessons learned.

Modal Analysis of the Line Inspection Robot's Guide Platform

2014 ◽  
Vol 685 ◽  
pp. 265-270 ◽  
Author(s):  
Xu Dong ◽  
Zhong Cai Zheng ◽  
Yan Gao ◽  
Hai Yong Xiao
Keyword(s):  
Modal Analysis ◽  
High Voltage ◽  
Optimization Design ◽  
Three Dimensional ◽  
Power Lines ◽  
Inspection Robot ◽  
Dimensional Models ◽  
Three Dimensional Models ◽  
High Voltage Power Lines

Line inspection robot detects defects in high-voltage power lines, and it exists the instability of the movement in the process of surmounting obstacles due to its own gravity and vibration. So the robot is easily falling from the lines. The vibration sources of the line inspection robot with double manipulators of antisymmetric structure are mainly from the rotation of the walking motors of holding mechanism, the reversal motors of mechanical arm and driving motors of guide platform. This paper established the three-dimensional models of the line inspection robot's guide platform and conducted the statics and modal analysis. The results concluded the inherent frequencies and vibration modals of the guide platform, and then provided a theoretical guidance for the optimization design of the guide platform.

Arsenic Disulfide Combined with L-Buthionine-(S, R)-Sulfoximine Induces Synergistic Antitumor Effects in Two-Dimensional and Three-Dimensional Models of MCF-7 Breast Carcinoma Cells

2019 ◽  
Vol 47 (05) ◽  
pp. 1149-1170 ◽  
Author(s):  
Yuxue Zhao ◽  
Sachiko Tanaka ◽  
Bo Yuan ◽  
Kentaro Sugiyama ◽  
Kenji Onda ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Antitumor Effects ◽  
Anticancer Efficacy ◽  
Three Dimensional Models ◽  
Novel Strategy ◽  
2D And 3D ◽  
Combinatorial Treatment ◽  
Mcf 7

Three-dimensionally (3D) cultured tumor cells (spheroids) exhibit more resistance to therapeutic agents than the cells cultured in traditional two-dimensional (2D) system (monolayers). We previously demonstrated that arsenic disulfide (As2[Formula: see text] exerted significant anticancer efficacies in both 2D- and 3D-cultured MCF-7 cells, whereas 3D spheroids were shown to be resistant to the As2S2 treatment. L-buthionine-(S, R)-sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, has been regarded to be a potent candidate for combinatorial treatment due to its GSH modulation function. In the present study, we introduced BSO in combination with As2S2 at a low concentration to investigate the possible enhancing anticancer efficacy by the combinatorial treatment on 2D- and 3D-cultured MCF-7 cells. Our results presented for the first time that the combination of As2S2 and BSO exerted potent anticancer synergism in both MCF-7 monolayers and spheroids. The [Formula: see text] values of As2S2 in combinatorial treatment were significantly lower than those in treatment of As2S2 alone in both 2D- and 3D-cultured MCF-7 cells ([Formula: see text], respectively). In addition, augmented induction of apoptosis and enhanced cell cycle arrest along with the regulation of apoptosis- and cell cycle-related proteins, as well as synergistic inhibitions of PI3K/Akt signals, were also observed following co-treatment of As2S2 and BSO. Notably, the combinatorial treatment significantly decreased the cellular GSH levels in both 2D- and 3D-cultured MCF-7 cells in comparison with each agent alone ([Formula: see text] in each). Our results suggest that the combinatorial treatment with As2S2 and BSO could be a promising novel strategy to reverse arsenic resistance in human breast cancer.

Modal analysis of the diaphragm of the semicircular canal

2001 ◽  
Vol 11 (1) ◽  
pp. 43-54
Author(s):  
E. Njeugna ◽  
C.M. Kopp ◽  
J.-L. Eichhorn
Keyword(s):  
Modal Analysis ◽  
Semicircular Canal ◽  
Static Pressure ◽  
Three Dimensional ◽  
Vibration Modes ◽  
Modes Of Vibration ◽  
Crista Ampullaris ◽  
Static Pressure Difference ◽  
Three Dimensional Models ◽  
Internal Viscosity

The aim of this paper is to determine the domain of validity of calculated quasi-static deformations of the cupula and of ciliar deflections on the crista ampullaris. Several three-dimensional models of the isolated ampullar diaphragm of the human semicircular canal and of that of the frog are studied theoretically by modal analysis. The four first modes of vibration are determined for each structure. Numerical simulations prove that for the first mode of vibration, the cupular deformation has the same shape as that obtained by applying a static pressure difference across the ampullar diaphragm. We studied also the effect of the mechanical properties (Young's modulus and Poisson's coefficient) of the components of the ampullar diaphragm on the vibration modes and their frequencies. The condition, which must be satisfied by the cupular internal viscosity, to have resonance near the natural frequency of the ampullar diaphragm is determined.

Modal Analysis of the Line Inspection Robot's Manipulator

2014 ◽  
Vol 681 ◽  
pp. 100-105
Author(s):  
Jian Li ◽  
Xu Dong ◽  
Zhong Cai Zheng ◽  
Yan Gao ◽  
Zhen Ting Jiang ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Theoretical Basis ◽  
Three Dimensional ◽  
Robot Arm ◽  
Overhead Line ◽  
Post Processing ◽  
Low Frequencies ◽  
Overhead Lines ◽  
Inspection Robot ◽  
Three Dimensional Models

The Line Inspection Robot is used to detect the line's defects when it walks on the overhead lines. It will be swinging under its own vibration and the action of wind , due to the robot arms hanging on overhead line alone ,so the dynamic characteristics of robot arm cannot be ignored. In this paper, we establish three-dimensional models of the line inspection robot's manipulator with double manipulators of antisymmetric structure, and conduct solving and post-processing of statics and modal analysis after meshing and applying constraints. The manipulator's low frequencies and vibration modals are drawn, so we can provide a theoretical basis for the reasonable optimization improvements to the line inspection robot's manipulator with double manipulators of antisymmetric structure.

Steam-turbine casing flanges: A three-dimensional photoelastic study

1971 ◽  
Vol 6 (3) ◽  
pp. 193-203 ◽  
Author(s):  
H W McKenzie ◽  
D J White ◽  
S Snell
Keyword(s):  
Pressure Distribution ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Interface Pressure ◽  
Centre Line ◽  
Bolt Preload ◽  
Small Pitch ◽  
Turbine Casing ◽  
Bolt Holes ◽  
Three Dimensional Models

Photoelastic tests have been made on simplified three-dimensional models of a steam-turbine casing subjected to bolt preload and internal pressure. An examination was made of the flange interface-pressure distribution between adjacent bolt holes for two different values of bolt pitch. The results revealed that for both bolt pitches investigated in these tests, the minimum interface pressure at the inner edge occurred at a position corresponding to the bolt centre-line. The maximum interface pressure occurred on the inner edge at the mid-pitch position for the small pitch and on the inner edge at a distance of approximately one-quarter of the pitch from the bolt centre-line for the large pitch. The overall flange interface-pressure distribution had a minimum at a position approximately mid-way between two adjacent bolts and one-third of the flange width from the inner edge. It has been verified from these tests that the determination of flange parameters using the two-dimensional design curves described in an earlier paper is valid for practical designs of flange.

Plastic replicas as three-dimensional models of pulps

1975 ◽  
Vol 39 (8) ◽  
pp. 544-546
Author(s):  
HL Wakkerman ◽  
GS The ◽  
AJ Spanauf
Keyword(s):  
Three Dimensional ◽  
Dimensional Models ◽  
Three Dimensional Models

Validation of a Belt Model for Prediction of Hub Forces from a Rolling Tire4

2009 ◽  
Vol 37 (2) ◽  
pp. 62-102 ◽  
Author(s):  
C. Lecomte ◽  
W. R. Graham ◽  
D. J. O’Boy
Keyword(s):  
Internal Pressure ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Prediction Method ◽  
Analytical Models ◽  
Beam Model ◽  
Impedance Boundary ◽  
Bending Waves ◽  
Tire Rotation ◽  
Three Dimensional Models

Abstract An integrated model is under development which will be able to predict the interior noise due to the vibrations of a rolling tire structurally transmitted to the hub of a vehicle. Here, the tire belt model used as part of this prediction method is first briefly presented and discussed, and it is then compared to other models available in the literature. This component will be linked to the tread blocks through normal and tangential forces and to the sidewalls through impedance boundary conditions. The tire belt is modeled as an orthotropic cylindrical ring of negligible thickness with rotational effects, internal pressure, and prestresses included. The associated equations of motion are derived by a variational approach and are investigated for both unforced and forced motions. The model supports extensional and bending waves, which are believed to be the important features to correctly predict the hub forces in the midfrequency (50–500 Hz) range of interest. The predicted waves and forced responses of a benchmark structure are compared to the predictions of several alternative analytical models: two three dimensional models that can support multiple isotropic layers, one of these models include curvature and the other one is flat; a one-dimensional beam model which does not consider axial variations; and several shell models. Finally, the effects of internal pressure, prestress, curvature, and tire rotation on free waves are discussed.

In Silico Identification and Molecular Characterization of Extracellular Cathepsin L Proteases from Giardia duodenalis

2020 ◽  
Vol 17 (4) ◽  
pp. 342-351
Author(s):  
Sergio A. Durán-Pérez ◽  
José G. Rendón-Maldonado ◽  
Lucio de Jesús Hernandez-Diaz ◽  
Annete I. Apodaca-Medina ◽  
Maribel Jiménez-Edeza ◽  
...  
Keyword(s):  
In Silico ◽  
Cathepsin L ◽  
Three Dimensional ◽  
Giardia Duodenalis ◽  
Evolutionary Genetics ◽  
Extracellular Proteins ◽  
In Silico Identification ◽  
Dimensional Models ◽  
Three Dimensional Models

Background: The protozoan Giardia duodenalis, which causes giardiasis, is an intestinal parasite that commonly affects humans, mainly pre-school children. Although there are asymptomatic cases, the main clinical features are chronic and acute diarrhea, nausea, abdominal pain, and malabsorption syndrome. Little is currently known about the virulence of the parasite, but some cases of chronic gastrointestinal alterations post-infection have been reported even when the infection was asymptomatic, suggesting that the cathepsin L proteases of the parasite may be involved in the damage at the level of the gastrointestinal mucosa. Objective: The aim of this study was the in silico identification and characterization of extracellular cathepsin L proteases in the proteome of G. duodenalis. Methods: The NP_001903 sequence of cathepsin L protease from Homo sapienswas searched against the Giardia duodenalisproteome. The subcellular localization of Giardia duodenaliscathepsin L proteases was performed in the DeepLoc-1.0 server. The construction of a phylogenetic tree of the extracellular proteins was carried out using the Molecular Evolutionary Genetics Analysis software (MEGA X). The Robetta server was used for the construction of the three-dimensional models. The search for possible inhibitors of the extracellular cathepsin L proteases of Giardia duodenaliswas performed by entering the three-dimensional structures in the FINDSITEcomb drug discovery tool. Results: Based on the amino acid sequence of cathepsin L from Homo sapiens, 8 protein sequences were identified that have in their modular structure the Pept_C1A domain characteristic of cathepsins and two of these proteins (XP_001704423 and XP_001704424) are located extracellularly. Threedimensional models were designed for both extracellular proteins and several inhibitory ligands with a score greater than 0.9 were identified. In vitrostudies are required to corroborate if these two extracellular proteins play a role in the virulence of Giardia duodenalisand to discover ligands that may be useful as therapeutic targets that interfere in the mechanism of pathogenesis generated by the parasite. Conclusion: In silicoanalysis identified two proteins in the Giardia duodenalisprotein repertoire whose characteristics allowed them to be classified as cathepsin L proteases, which may be secreted into the extracellular medium to act as virulence factors. Three-dimensional models of both proteins allowed the identification of inhibitory ligands with a high score. The results suggest that administration of those compounds might be used to block the endopeptidase activity of the extracellular cathepsin L proteases, interfering with the mechanisms of pathogenesis of the protozoan parasite Giardia duodenalis.

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

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