Refined calculations for the strength and stiffness of cold-formed steel diaphragms

1979 ◽  
Vol 6 (2) ◽  
pp. 268-275
Author(s):  
H. K. Ha ◽  
N. El-Hakim ◽  
P. Fazio
Keyword(s):  
Internal Force ◽  
Test Results ◽  
Finite Element Analyses ◽  
Simple Method ◽  
Shear Transfer ◽  
Wide Range ◽  
Cold Formed Steel ◽  
Strength And Stiffness ◽  
Assumed Mode ◽  
Good Agreement

A refined yet simple method is presented for the analysis of cold-formed metal shear diaphragms. Expressions for the deflections and fastener forces are developed based on an assumed mode of deformation in conjunction with a refined set of internal force distributions. The formulas are applicable to both 'direct' and 'indirect' shear-transfer cases. The generality and the accuracy of the derived expressions are illustrated in an application of the method to the analysis of eight diaphragms having a wide range of constructional details. The results of calculations for the diaphragm flexibility and strength are in good agreement with test results and with finite-element analyses.

Piston-Lift Check Valve Flow Verification Using CFD

2018 ◽  
Author(s):  
Matthew Laney ◽  
Ronald Farrell
Keyword(s):  
Flow Characteristics ◽  
Check Valve ◽  
Valve Lift ◽  
Cfd Analysis ◽  
Test Results ◽  
Finite Element Software ◽  
Translational Movement ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Computational Fluid Dynamics (CFD) is increasingly being used as a reliable method for determining flow characteristics of a wide range of flow situations. This paper presents an extension of paper PVP2017-66269, “Check Valve Flow and Disk Lift Simulation Using CFD” [1], and utilizes some of the same concepts to characterize flow through piston-lift check valves. The previous example considered a swing check valve involving rotational movement; this example considers a vertical lift piston check valve involving translational movement. Specifically, CFD was used to determine valve flow coefficients (CV) as a function of disk lift position as well as to determine the flow rate required to achieve full open or predict intermediate disk lift positions. The CFX application, which is part of the ANSYS suite of finite element software, was used to determine the flow characteristics. As presented in PVP2017-66269, balancing flow-induced forces on the check element and considering the disk assembly weight, the valve lift behavior can be predicted. Results from the CFX analysis were compared to recent test results of a skirted disk-piston check valve and previous test results of a standard disk-piston check valve. The results showed good agreement in most cases. This validates that flow characteristics across valves with different types of check elements at different disk lift positions can be reliably predicted using CFD analysis. It is important to note that while the test results and CFD analysis showed good agreement, it was vital that actual testing be performed in order to validate the approach. This follows the recommendation outlined in the previous paper.

Fatiguing of Rubber-Rubber Interfaces

1983 ◽  
Vol 56 (4) ◽  
pp. 838-844 ◽  
Author(s):  
G. S. Fielding-Russell ◽  
R. L. Rongone
Keyword(s):  
Time To Failure ◽  
Test Results ◽  
Mechanical Fatigue ◽  
Wide Range ◽  
Mode Of Failure ◽  
Metal Rubber ◽  
Fracture Theory ◽  
Failure Correlation ◽  
Growth Constants ◽  
Good Agreement

Abstract Mechanical fatigue results of three rubber systems, obtained by using a Painter adhesion testpiece, modified in such a way that it mates rubber-rubber surfaces (rather than metal-rubber surfaces) indicated that the testpiece is capable of fatiguing a rubber-rubber interface and therefore is useful for evaluating rubber-rubber joints. The mode of failure, correlation of the present results with static interfacial results, and the wide range of crack growth constants all indicated interfacial fatiguing. Test results, i.e., time to failure versus applied dynamic load, gave good agreement with established rubber fracture theory.

Design of a 33-Knot Aluminum Catamaran Ferry

2000 ◽  
Vol 37 (02) ◽  
pp. 88-99
Author(s):  
R. G. Latorre ◽  
P. D. Herrington
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Speed ◽  
Frame Structure ◽  
Test Results ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
Floating Frame ◽  
Good Agreement ◽  
Panel Design

This paper presents the results of an investigation on the suitability of using hull panels with alternating fixed and floating frames for a 30–40 knot aluminum catamaran ferry. A prototype 4.6 m × 1.8 m bottom hull panel with alternating frames is analyzed numerically and physically tested. The corresponding finite-element analyses and test results are in good agreement. The results show that the floating frame hull panel design is a feasible structure for an aluminum catamaran. The floating frame structure was then used for a 33-knot, 250-passenger aluminum catamaran ferry designed to meet the ABS High Speed Craft rules. A midship section of the catamaran hull was analyzed using the finite-element method. Catamaran weight estimates, heave and pitch motions, and powering estimates are also provided. The results show that the alternating floating frame structure was within the ABS rules stress allowables.

Testing and Analysis of a New Lead-Extrusion Damper

2002 ◽  
Author(s):  
C. S. Tsai ◽  
W. S. Lai ◽  
C. W. Chang ◽  
M. C. Li
Keyword(s):  
Laboratory Test ◽  
Hysteresis Loop ◽  
Energy Absorption ◽  
Analytical Model ◽  
Internal Force ◽  
Experimental Results ◽  
Test Results ◽  
Wave Type ◽  
Maximum Capacity ◽  
Good Agreement

The purpose of this study is to test and explore the characteristics of the new lead-extrusion damper (LED), which is manufactured in the department of Civil Engineering of Feng-Chia University. The Stroke of the tested damper is ±10 mm and the maximum movement of the laboratory test is ±5mm, which is provided by the MTS (machine with a maximum capacity of 25tons). The test results have proved that the new LED possesses excellent capability for energy absorption. The hysteresis loop behaves like “plastic solids” or “coulomb dampers”. The internal force and the speed of the movement are correlated while the damper is subjected to sin wave type of loadings. By comparing the numerical results obtained from the proposed analytical model with experimental results under various displacements and frequencies, it is concluded that a good agreement between the computational and experimental results has been achieved.

EFFECTS OF VERTICAL SLOTTED HOLE ON COLD FORMED STEEL Z-SHAPE LAPPED PURLINS

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
L. Xu ◽  
J. Liu ◽  
S. Fox ◽  
Y. Liu
Keyword(s):  
Flexural Strength ◽  
Test Results ◽  
Design Practice ◽  
Flexural Behaviour ◽  
Structural Behaviour ◽  
Building Roof ◽  
Current Design ◽  
Cold Formed Steel ◽  
Strength And Stiffness ◽  
Metal Building

Lapped joints of cold-formed steel Z-shaped purlins are extensively used in metal building roof construction to create multi-span purlin systems. Conventionally, round holes are used in the lapped purlin connections. With the advantage of providing extra installation tolerance, vertical slotted holes are widely used in the lapped joints of cold-formed steel Z-shaped purlin systems to simplify and expedite the erection of multi-span purlin roof systems. However, the current design practice is based on the research for the lapped connections with round holes. Almost no research has been conducted to investigate effects of vertical holes on the flexural behaviour of cold-formed steel Z-shaped purlins. To investigate the effects of vertical slotted holes on the structural behaviour of lapped cold-formed steel Z-shaped purlins, tests were performed on the lapped purlins with different lap lengths, purlin depths, thicknesses and spans. The results show that the flexural strength and stiffness of the lapped purlins with vertical slotted holes are primarily influenced by three parameters, i.e., the ratio of lap length to purlin depth, the ratio of lap length to purlin thickness, and the ratio of purlin depth to purlin thickness. Based on the test results, design recommendations are proposed for designing lapped cold-formed steel Z-shaped purlins with vertical slotted holes.

Correlation Between Road Wear of Tires and Computer Road Wear Simulation Using Laboratory Abrasion Data

2004 ◽  
Vol 77 (5) ◽  
pp. 791-814 ◽  
Author(s):  
K. A. Grosch
Keyword(s):  
Computer Program ◽  
Test System ◽  
Wear Testing ◽  
Test Results ◽  
Wear Simulation ◽  
General Validity ◽  
Testing Conditions ◽  
Abrasion Test ◽  
Wide Range ◽  
Good Agreement

Abstract Any laboratory abrasion method has to take account of the well known fact that the ranking and wear rating of tire tread compounds depend strongly on the testing conditions. The severity of road tests, particularly when carried out with customer vehicles is not well defined. Any result obtained in this way is a spot reading which contains no information about its general validity. A road wear computer program was designed which is able to simulate a very wide range of road wear testing severities and the effect which they have on achievable mileage and wear rating of tread compounds. The program uses the laboratory abrasion test system designed to be used with the Laboratory Abrasion Tester designated as LAT 100. It is shown that good agreement is obtained with actual road test results, not only for the rating of compounds but also for the achieved mileages.

A Simple Method for Predicting the Maximum Squat of a High-Speed Displacement Ship

2006 ◽  
Vol 43 (03) ◽  
pp. 146-151
Author(s):  
Tim Gourlay
Keyword(s):  
Satisfactory Agreement ◽  
Model Test ◽  
High Speed ◽  
Simple Formula ◽  
Test Results ◽  
Simple Method ◽  
Wide Range ◽  
Speed Range ◽  
Calm Water ◽  
Hull Forms

A simple formula is developed for predicting the maximum squat of a displacement ship as it passes through the transcritical speed range. This is given in terms of a maximum sinkage coefficient, which is almost constant across a wide range of hull forms. Satisfactory agreement is shown with model test results, and it is shown that large stern sinkages in the order of 3 to 6 meters are predicted for frigate and destroyer type hulls in shallow calm water.

scholarly journals Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy

2020 ◽  
Vol 499 (3) ◽  
pp. 4418-4431 ◽  
Author(s):  
Sujatha Ramakrishnan ◽  
Aseem Paranjape
Keyword(s):  
Dark Matter ◽  
High Precision ◽  
Gaussian Distribution ◽  
Initial Perturbation ◽  
Analytical Framework ◽  
Web Environment ◽  
Wide Range ◽  
Galaxy Assembly ◽  
Very High ◽  
Good Agreement

ABSTRACT We use the Separate Universe technique to calibrate the dependence of linear and quadratic halo bias b1 and b2 on the local cosmic web environment of dark matter haloes. We do this by measuring the response of halo abundances at fixed mass and cosmic web tidal anisotropy α to an infinite wavelength initial perturbation. We augment our measurements with an analytical framework developed in earlier work that exploits the near-lognormal shape of the distribution of α and results in very high precision calibrations. We present convenient fitting functions for the dependence of b1 and b2 on α over a wide range of halo mass for redshifts 0 ≤ z ≤ 1. Our calibration of b2(α) is the first demonstration to date of the dependence of non-linear bias on the local web environment. Motivated by previous results that showed that α is the primary indicator of halo assembly bias for a number of halo properties beyond halo mass, we then extend our analytical framework to accommodate the dependence of b1 and b2 on any such secondary property that has, or can be monotonically transformed to have, a Gaussian distribution. We demonstrate this technique for the specific case of halo concentration, finding good agreement with previous results. Our calibrations will be useful for a variety of halo model analyses focusing on galaxy assembly bias, as well as analytical forecasts of the potential for using α as a segregating variable in multitracer analyses.

scholarly journals Spine Examination during COVID-19 Pandemic via Video Consultation

2021 ◽  
Author(s):  
Tom Jansen ◽  
Martin Gathen ◽  
Amadeo Touet ◽  
Hans Goost ◽  
Dieter Christian Wirtz ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Range Of Motion ◽  
Test Results ◽  
Risk Of Infection ◽  
Face To Face ◽  
Reliable Tool ◽  
Provocation Tests ◽  
Active Range Of Motion ◽  
Video Consultation ◽  
Good Agreement

Abstract Introduction During the current COVID-19 pandemic video consultations are increasingly common in order to minimize the risk of infection for staff and patients. The aim of this study was to evaluate the feasibility of a spine examination via video. Methods A total of 43 patients were recruited. Each participant underwent a video-based (VB) and a conventional face-to-face (FTF) spine examination. Pain intensity, active range of motion, inspection, a neurophysiologic basic exam and provocations tests were evaluated using video-based and face-to-face methods. Results The intra-rater reliability (IRR) was measured between both examinations. Good to very good IRR values were obtained in inspection (Kappa between 0,752 und 0,944), active range of motion and basic neurophysiological examination (Kappa between 0,659 und 0,969). Only moderate matches were found in specific provocation tests (Kappa between 0,407 und 0,938). A video-based spine examination is a reliable tool for measuring pain intensity, active range of motion and a basic neurophysiologic exam. Conclusion A basic spine examination during a video consultation is possible. A good agreement of the test results between video-based and face-to-face examination could be found.

Design of combined brake system for light weight scooters

2021 ◽  
pp. 095440702110240
Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang
Keyword(s):  
Ride Comfort ◽  
Brake System ◽  
Force Distribution ◽  
Test Results ◽  
Systematic Method ◽  
Braking Performance ◽  
Evaluation Indexes ◽  
Low Costs ◽  
Braking Force ◽  
Good Agreement

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.

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