Shear-moment transfer in flat plates

1986 ◽  
Vol 13 (3) ◽  
pp. 327-334
Author(s):  
Sidney H. Simmonds ◽  
Brian W. Doblanko
Keyword(s):  
Shear Stress ◽  
Flat Plate ◽  
Key Words ◽  
Concrete Slabs ◽  
Shear Stresses ◽  
Flat Plates ◽  
Design Factor ◽  
Critical Design ◽  
Design Charts

For many concrete slabs without beams, the critical design factor is the shear stress in the vicinity of the column–slab junction. This is particularly so near edge and corner columns where the shear stresses due to the unbalanced moments may account for the major portion of these stresses. The determination of these design stresses in accordance with the provisions of Standard CAN3-A23.3-M84 is both time consuming and subject to numerical mistakes. Based on these provisions, design charts were developed, which greatly reduce the amount of calculation required and are suitable for routine use in the design of slabs. The use of the charts is illustrated by examples. Key words: design, flat plate, moment transfer, reinforced concrete, shear, slabs.

scholarly journals A Generalized Method for Flat Plates Impact Detection and Location

2013 ◽  
Vol 543 ◽  
pp. 171-175
Author(s):  
Jose Andrés Somolinos ◽  
Rafael Morales ◽  
Carlos Morón ◽  
Alfonso Garcia
Keyword(s):  
Signal Processing ◽  
Flat Plate ◽  
Acoustic Signal ◽  
Experimental Results ◽  
Piezoelectric Sensors ◽  
Experimental Setup ◽  
Flat Plates ◽  
Impact Detection ◽  
Timing Difference

In the last years, many analyses from acoustic signal processing have been used for different applications. In most cases, these sensor systems are based on the determination of times of flight for signals from every transducer. This paper presents a flat plate generalization method for impact detection and location over linear links or bars-based structures. The use of three piezoelectric sensors allow to achieve the position and impact time while the use of additional sensors lets cover a larger area of detection and avoid wrong timing difference measurements. An experimental setup and some experimental results are briefly presented.

Design Charts for Symmetrical Ring Girders

1957 ◽  
Vol 24 (1) ◽  
pp. 144-147
Author(s):  
G. P. Fisher
Keyword(s):  
Energy Analysis ◽  
Bending Moment ◽  
Bending Moments ◽  
Bending Energy ◽  
Normal Loading ◽  
Critical Design ◽  
Design Charts ◽  
Ring Location

Abstract Charts, based on classical bending-energy analysis, are presented for the determination of critical design moments in symmetrical ring girders varying in shape from circular through round to sharp-cornered rings. The girders are subjected to uniform normal loading in the plane of the ring. Location and magnitude of all critical bending moments are given, from which the maximum bending moment is easily selected.

Trockenumformung strukturierter Halbzeuge aus 16MnCr5 und 42CrMo4*/Dry forming of surface structured workpiece made of 16MnCr5 and 42CrMo4 - Determination of friction shear stress by means of a pin-on-cCylinder Tribometer

2016 ◽  
Vol 106 (10) ◽  
pp. 712-718
Author(s):  
R. Hild ◽  
D. Trauth ◽  
P. Mattfeld ◽  
S. Bastürk ◽  
T. Brögelmann ◽  
...  
Keyword(s):  
Shear Stress ◽  
Metal Forming ◽  
Shear Stresses ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Dry Forming ◽  
Tool Coatings ◽  
Green Factory

Der Einsatz von Schmierstoffen gestattet bisher die Umformung von Massivbauteilen. In der „Green Factory“ wird auf die Verwendung dieser Schmierstoffe verzichtet. Daraus resultieren unbekannte Anforderungen an das trockene Tribosystem. Selbstschmierende Werkzeugbeschichtung und strukturierte Halbzeuge ermöglichen das trockene Tribosystem und reduzieren die Reibschubspannung. Der Fachbeitrag zeigt die Auswirkungen von Oberflächenstrukturen auf Halbzeugen auf die Reibschubspannung.   Solid and liquid lubricants enable bulk metal forming processes. In the “Green Factory”, the application of lubricants is to be avoided. The absence of lubricants results in unknown demands on a dry tribosystem. Possible enablers of the dry tribosystem are self-lubricating tool coatings and structured workpieces that lower the friction shear stresses. This contribution shows how the workpiece structuring influences the friction shear stress.

scholarly journals Shear stress caused by artificial raindrop impact at the soil surface

2017 ◽  
Vol 4 ◽  
pp. 27-36
Author(s):  
Olgarenko G.V. ◽  
Bryl S.V. ◽  
Zverkov M.S.
Keyword(s):  
Shear Stress ◽  
Laboratory Testing ◽  
Strain State ◽  
Soil Surface ◽  
Shear Stresses ◽  
Significance Level ◽  
Rain Erosion ◽  
Raindrop Impact

The purpose of this research is to develop methods of determination of the stress-strain state of the soil due to the drop impact of the artificial rain to increase the accuracy and simplify the research of drop and rain erosion, field and laboratory testing of sprinkler equipment. The calculation of the shear stresses arising at the point of impact drops of art ificial rain on soil, the role of these stresses in the mechanism for the development of drop and rain erosion, the expediency this value for testing irrigation equipment. For impacts of drop with a diameter of 1.73 mm on the basis of the magnitude of the shear stress was 158.44 ± 7.32 kPa (significance level p < 0.001) to 281.76 ± 11.18 kPa (p < 0.001) in the fall drops with a height from 1.0 до 2.5 m, respectively. For the case of hitting the ground drops with a diameter of 2.73 mm shear stress was 196.51 ± 5.72 kPa (p < 0.001) to 339.71 ± 33.35 kPa (p < 0.001) in the fall drops with a height from 1.0 to 2.5 m, respectively. The values of shear stress τ significantly correlated with the values of the drop height h (for drops with a diameter dd = 1.73 mm correlation coefficient r = 0.963 ± 0.029, p < 0.001; for dd = 2.73 mm r = 0.977 ± 0.014, p < 0.001). The median time of impact of drop 1.73 mm by soil was (5.95 ± 0.57) ∙ 10–5 sec., for the drop with a diameter 2.73 mm the time was (6.53 ± 0.67) ∙ 10–5 sec. Weber numbers We for the drop with the diameter of 1.73 mm were 459...1156, for the drop with the diameter of 2.73 mm – 728...1829.

On the Accuracy of Wall Shear Stress Using DPIV

Volume 1 ◽  
2004 ◽  
Author(s):  
Ali Etebari ◽  
Jason Carneal ◽  
Pavlos P. Vlachos
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Moving Boundaries ◽  
Viscous Drag ◽  
Shear Stresses ◽  
Indirect Estimation ◽  
Stress Estimation ◽  
Wall Shear ◽  
Near Wall

Wall shear stress measurements are important for a variety of fluid mechanics phenomena and engineering applications ranging from estimation of viscous drag to the regulation of endothelial cell function in arterial flows [1–5]. Although DPIV has emerged over the past years as the method of choice for global non-invasive optical flow diagnostics [6–13] the issues associated with the indirect estimation of wall shear stresses from DPIV measured velocities have not been sufficiently addressed. The challenge is even more significant in the presence of deformable and dynamically moving boundaries. In particular such measurements require accurate determination of wall position, near-wall velocity measurements using DPIV algorithms, and the indirect estimation of the velocity derivatives in order to evaluate the shear stress. Dynamically moving boundaries, whether rigid or compliant, require special consideration, as the boundary position must be determined accurately as a function of space and time. It is necessary to quantify the accuracy of each measurement that contributes to the error of the wall shear stress estimation. In this work we decompose the problem into the following three aspects: (a) determination of the exact boundary points (b) DPIV velocity measurement uncertainty in the near wall region. (c) velocity derivative error. Methodologies and improvements addressing each aspect individually are proposed and a systematic parametric study of the related error is performed. To our knowledge, this is the first detailed parametric effort to quantify the errors associated with wall shear stress estimation from DPIV velocities.

Rheological Properties of Two Unvulcanized Rubber Compounds as Determined on an Extrusion and a Rotational Viscometer

1964 ◽  
Vol 37 (2) ◽  
pp. 491-502
Author(s):  
F. E. Devine ◽  
J. A. Ross
Keyword(s):  
Shear Stress ◽  
Rheological Properties ◽  
Extrusion Pressure ◽  
Rheological Parameters ◽  
Shear Stresses ◽  
Extrude Material ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
Rubber Compounds

Abstract The viscometer manufactured by A. Macklow-Smith Ltd., which operates at constant rate of extrusion, is a capillary instrument designed for the determination of flow properties of plastics. The instrument has been used for examining the rheological characteristics of rubber compounds and it has been possible to derive the shear stresses required to extrude material at various shear rates between 2 and 1050 sec−1. The general method of operation of the instrument for this purpose is discussed including the determination of preheat time before extrusion and the aspect of incipient vulcanization in the viscometer during extrusion. The effects of various lengths and diameters of dies on rheological parameters and entrance effects are discussed. An important aspect of the work is the observation of a piston height effect in the extruder barrel. Two different compounded polymers have been examined and in one case, the extrusion pressure was found to decrease with piston height whilst in the other highly elastic material, it was found that as the piston descended, the extrusion pressure increased to an equilibrium value. The importance of this effect in obtaining consistent shear stress data is discussed. Results of the work have been expressed in terms of apparent viscosity and also in terms of the parameters which describe a power law relating shear stress and shear rate within the capillary die. Rheological data have been obtained at various temperatures within the range of processing temperatures of the compounds. The effects on rheological properties of mastication and relaxation time after mastication have been examined. Results have been compared with figures obtained on conventional laboratory viscometers such as the Mooney Plastometer and the Wallace Rapid Plastimeter. A biconical, rotational viscometer has also been used at the lower range of shear rates and the results are compared with those obtained from the extrusion viscometer.

scholarly journals Velocity Boundary Layer Analysis of a Flat Plate Heat Exchanger in Laminar Flow: A Case Study

2012 ◽  
Vol 2 (6) ◽  
pp. 310-314
Author(s):  
M. Mirdrikvand ◽  
B. Roozbehani ◽  
S. I. Moqadam ◽  
A. C. Roshan ◽  
Y. Ramezani
Keyword(s):  
Boundary Layer ◽  
Heat Exchanger ◽  
Laminar Flow ◽  
Flat Plate ◽  
Cfd Simulation ◽  
Plate Heat Exchanger ◽  
Shear Stresses ◽  
Flat Plates ◽  
Plate Heat ◽  
Velocity Boundary Layer

In this article, a behavioral analysis of velocity boundary layer in a flat plate heat exchanger in laminar flow condition through CFD simulation using FLUENT software is done. The main objective of this study is to determine the velocity vectors between the flat plates of the heat exchanger. In addition, wake occurrence, differences of velocity at different surfaces between plates, angles of velocity vectors and the effect of wake phenomenon on the shear stresses exerted on the plates are discussed in detail. The study graphically illustrates results based on fluid’s behavior by a 3D and 2D simulation with air and water as cold and hot streams that affect plate’s situation and its hydro dynamical operations. Consequently, some important design features regarding wake point occurrence and pressure loss are investigated. In addition, eddy current and reverse flows in the wake area and the angles of the velocity vectors are described.

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part IV: Laboratory Measurement of Mechanical Properties and Mechanical Actions of Tires Relating to Treadwear

1986 ◽  
Vol 14 (4) ◽  
pp. 264-291
Author(s):  
K. L. Oblizajek ◽  
A. G. Veith
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Contact Zone ◽  
Flexural Rigidity ◽  
Comprehensive Evaluation ◽  
Shear Stiffness ◽  
Shear Stresses ◽  
Lateral Shear ◽  
Band Bending ◽  
Tread Rubber

Abstract Treadwear is explained by specific mechanical properties and actions of tires. Rubber shear stresses in the contact zone between the tire and the road become large at large slip angles. When normal stresses are insufficient to prevent sliding at the rear of the footprint, wear occurs at a rate that depends on test severity. Two experimental approaches are described to relate treadwear to tire characteristics. The first uses transducers imbedded in a simulated road surface to obtain direct measurements of contact stresses on the loaded, freely-rolling, steered tires. The second approach is developed with the aid of a simple carcass, tread-band, tread-rubber tire model. Various tire structural configurations; characterized by carcass spring rate, edgewise flexural band stiffness, and tread rubber shear stiffness; are simulated and lateral shear stress response in the contact zone is determined. Tires featuring high band stiffness and low carcass stiffness generate lower lateral shear stress levels. Furthermore, coupling of tread-rubber stiffness and band flexural rigidity are important in determining level of shear stresses. Laboratory measurements with the described apparatus produced values of tread-band bending and carcass lateral stiffness for several tire constructions. Good correlation is shown between treadwear and a broad range of tire stiffness and test course severities.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

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