scholarly journals Instrumentação da pista circular experimental do IPR/DNER

TRANSPORTES ◽  
1999 ◽  
Vol 7 (2) ◽  
Author(s):  
Prepredígna D. E. Almeida da Silva ◽  
Laura Maria Goretti da Motta
Keyword(s):  
Flexible Pavements ◽  
Computer Programs ◽  
Strain Gages ◽  
Load Cells ◽  
Circular Track ◽  
Pavement Layers ◽  
Pavement Instrumentation

<p>Faz-se uma breve abordagem sobre as principais experiências brasileiras em instrumentação de pavimentos no campo. Apresenta-se ainda, a instrumentação da Pista Circular Experimental do IPR/DNER, realizada em 1998 através de convênio firmado entre o DNER e a ABCP, para estudar o recapeamento de pavimentos flexíveis com concreto - <em>whitetopping. </em>Esta instrumentação foi composta de seis extensômetros e duas células de carga embutidos nas camadas do pavimento e os registros das medições destes sensores foram comparados com valores calculados utilizando os programas computacionais: EL5YM5, DIPLOMAT, ILSL2 e KENSLABS, obtendo resultados aproximados nesta comparação, principalmente com os programas EL5YM5 e DIPLOMAT (com aderência).</p><p>ABSTRACT</p><p>This work consists of a brief summary about the main Brazilian experiences in field pavement instrumentation. It also presents the IPR/DNER Experimental Circular Track, accomplished in 1998 through agreement between DNER and ABCP, to study the overlay of flexible pavements with concrete - whitetopping. This instrumentation was composed of six strain gages and two load cells embedded within the pavement layers. Recorded measurements of these sensors were compared to calculated values using the following computer programs: ELSYM5, DIPLOMAT, ILSL2 and KENSLABS, obtaining approximate results in this comparison, mainly with the programs ELSYM5 and DIPLOMAT (with adherence).</p>

Improvements in Data Acquisition for Propulsion Shaft Alignment

2015 ◽  
Author(s):  
W. David Joiner ◽  
Charles J. Cook
Keyword(s):  
Data Acquisition ◽  
Strain Gage ◽  
Strain Gages ◽  
Construction Process ◽  
Crucial Step ◽  
Ship Construction ◽  
Shaft Line ◽  
Load Cells ◽  
Shaft Alignment

Propulsion shaft alignment is a necessary and crucial step in the ship construction process, with manning and schedule constraints requiring accurate results as efficiently as possible. There are two methods for measuring the bearing loading along the shaft line: strain gages and load cells. The legacy method for using strain gages required a lot of man power and the legacy method for using load cells was dependent on the quality of machinist made available. Strain gages are the transducers of choice for measurement; however the data acquisition, especially for ships with long shafting systems, can require many strain gage positions and personnel to conduct tests. Load cells are used to validate the accuracy of the strain gage method and to calculate the shaft runout at each bearing location.

Smart Fasteners and Their Application in Flanged Joints

2011 ◽  
Author(s):  
Babak Eslami ◽  
Randy Ganye ◽  
Chris Bunai ◽  
Chandrasekhar Thamire
Keyword(s):  
Experimental Studies ◽  
Accurate Method ◽  
Industrial Applications ◽  
Current Paper ◽  
Strain Gages ◽  
Color Intensity ◽  
Tightening Torque ◽  
Load Cells ◽  
Torque Values

Fasteners are widely used in many industrial applications. Their function in many cases is to provide a leak-proof joint at the flange interface. To accomplish this function, fasteners must be clamped with appropriate force. In practice, it is difficult to measure such forces, intermittently or continuously. While measurement using load cells or strain gages is an available option, it tends to be expensive or infeasible due to the constraints imposed by the application. When tightening the fasteners initially or during maintenance, a less accurate method of specifying the bolt-tightening torque for achieving the necessary bolt force is widely followed in industry. These torque values are calculated using published design correlations [1]. Many factors affect such calculations: friction between the threads and collar and flange, age of the fasteners, assumptions about rigidity of the clamped components, being a few among those. Since specific values applicable for individual application are not always be known, fasteners are often over-tightened, resulting in increased stresses in the assembly elements or under tightened, resulting in leakages at the flange interfaces. In the current paper, we introduce the concept of smart fasteners that can visually indicate the tension they are subjected to, and validate it for a widely used industrial fastener size. Results from numerical and experimental studies conducted are presented for UNC 1/2 -13 × 4 1/4″ smart fasteners. Lastly, relationship between bolt-tightening torque and color intensity of the smart fasteners is provided.

Shortening Afloat of a Very Large Crude Carrier

1988 ◽  
Vol 25 (03) ◽  
pp. 163-171
Author(s):  
Carlo Podenzana-Bonvino ◽  
Rodolfo Tedeschi ◽  
Dario Boote ◽  
Marco Ferrando
Keyword(s):  
Weight Distribution ◽  
Shear Force ◽  
Theoretical Calculations ◽  
Bending Moment ◽  
Strain Gages ◽  
Initial Approach ◽  
Load Cells ◽  
Actual Load ◽  
Bending Stresses ◽  
Underwater Structures

A method for shortening afloat a very large crude carrier by means of a watertight transverse cofferdam is described. The method permits completely dry operations both when cutting the ship into three parts (while disconnecting the bottom plates and stiffeners) and when joining together the end sections (welding of the underwater structures). During the initial approach to the problem it became obvious, on the basis of theoretical calculations, that it would be impossible to eliminate the shear force and bending moment acting on the two sections to be cut; therefore, a series of linking means was designed to bear the residual shear and bending stresses which, to the authors' knowledge, were unavoidable in view of the uncertainties existing as to the longitudinal weight distribution. In order to ensure correct loading of these linking means, proper ballast transfers were arranged so that the ship was maintained in a slightly hogging condition while the bottom was being cut, and then in a slightly sagging condition while the deck was being cut. These linking devices were equipped with strain gages, so that they worked as actual load cells.

Shaft Alignment Methods with Strain Gages and Load Cells

1980 ◽  
Vol 17 (01) ◽  
pp. 8-15
Author(s):  
Robert B. Grant
Keyword(s):  
Reduction Gear ◽  
Bending Moments ◽  
Strain Gages ◽  
Direct Bearing ◽  
Load Cells ◽  
Shaft Alignment

The paper presents methods of aligning propulsion shafting using load cells for direct bearing reaction measurement and procedures for shafting alignment by measurement of shaft bending moments with strain gages. Additionally, a unique means of measuring reduction gear and stern tube bearing reactions is described.

Developing Large Slab Airport Runways for the Next Century

2019 ◽  
Vol 2673 (6) ◽  
pp. 524-535
Author(s):  
Stephen J. Roswurm ◽  
Chris Ramseyer
Keyword(s):  
Drying Shrinkage ◽  
Early Age ◽  
Strain Gages ◽  
Vibrating Wire ◽  
Type K ◽  
Wire Strain ◽  
Load Cells ◽  
Mineral Additive ◽  
Shrinkage Compensation ◽  
Airport Runway

The purpose of this research was to determine whether shrinkage-compensating concrete (SCC) made with Type K cement can create durable airport runways with fewer joints and reduced maintenance costs. The primary criterion examined was the ability of SCC to offset the effects of early-age drying shrinkage when the concrete is acted upon by external restraint. The interaction of restraint with SCC is important because restraint resists the expansive behavior that provides shrinkage compensation. Four sets of experiments were conducted, with increasing levels of Type K expansive mineral additive in each set. A set of test specimens consisted of four-inch diameter restrained columns. Each set consisted of three columns with varying degrees of stiffness in the restraint frame, including low, medium, and high-restraint stiffness. The medium-restraint column provides the theoretical response of new pavement cast against a mature slab, whereas the other two bracket the problem. The column specimens were instrumented using vibrating wire strain gages, which were embedded in the concrete, and load cells, which were affixed to the top of the columns. This research concludes that SCC can be effective even with a stiff boundary condition, and that SCC provides the potential for much longer-lasting airport runway slabs, as a result of reduced shrinkage and therefore fewer cracks.

scholarly journals Comparative analysis of stress distributions and displacements in rigid and flexible pavements via finite element method

2021 ◽  
Vol 20 (2) ◽  
pp. 321-331
Author(s):  
Sercan Serin ◽  
◽  
Muhammet Ahmet Oğuzhanoğlu ◽  
Cafer Kayadelen ◽  
◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Coating Layer ◽  
Flexible Pavements ◽  
Vertical Displacement ◽  
Stress Distributions ◽  
Empirical Formulas ◽  
Rigid Pavements ◽  
Pavement Layers ◽  
Element Method

In many countries of the world, rigid and flexible pavements are widely used. Some of the external factors such as stresses and displacements play major role in the design of pavement layers such as coating, base and sub-base. Although empirical formulas and methods were used in the calculation and design of the pavement layers, complexity of today's transportation engineering demands effectiveness of the empirical formulas were diminished. Nowadays complex problems can be easily simulated and solved thanks to the higher analysis capabilities of the computer-aided softwares. In this study, the stress distributions and displacements were examined under traffic loads in rigid and flexible pavements with different coating layer thicknesses (30 mm, 50mm, 70mm, 100 mm, and 150 mm) by using finite element method. As a result, the vertical displacement in the flexible pavements were obtained as 5% higher than the vertical displacement in the rigid pavements. Based on the stress distribution results, the stress values of flexible pavements were 60% lower than the stress values of the rigid pavements. Moreover, It was determined that the stresses in the rigid pavements remain in the coating layer, while the stresses in the flexible pavements reach the base and sub-base. In addition, regression models have been developed to predict stress and displacements by using layer thicknesses. High correlation and determination coefficient values (> 0.90) were achieved based on the regression analysis both in flexible and rigid pavements.

The Computational Sublime in Nick Montfort's ‘Round’ and ‘All the Names of God’

CounterText ◽  
2015 ◽  
Vol 1 (3) ◽  
pp. 348-365 ◽  
Author(s):  
Mario Aquilina
Keyword(s):  
Computer Code ◽  
Computer Programs ◽  
Literary Text ◽  
Text Generation ◽  
Mathematical Concepts ◽  
Literary Space

What if the post-literary also meant that which operates in a literary space (almost) devoid of language as we know it: for instance, a space in which language simply frames the literary or poetic rather than ‘containing’ it? What if the countertextual also meant the (en)countering of literary text with non-textual elements, such as mathematical concepts, or with texts that we would not normally think of as literary, such as computer code? This article addresses these issues in relation to Nick Montfort's #!, a 2014 print collection of poems that presents readers with the output of computer programs as well as the programs themselves, which are designed to operate on principles of text generation regulated by specific constraints. More specifically, it focuses on two works in the collection, ‘Round’ and ‘All the Names of God’, which are read in relation to the notions of the ‘computational sublime’ and the ‘event’.

Experimental Characterization of Mechanical Behavior of Cord-Rubber Composites

1982 ◽  
Vol 10 (1) ◽  
pp. 37-54 ◽  
Author(s):  
M. Kumar ◽  
C. W. Bert
Keyword(s):  
Response Characteristic ◽  
Cord Compression ◽  
Complete Characterization ◽  
Strain Response ◽  
Strain Gages ◽  
Experimental Characterization ◽  
Rubber Composites ◽  
Stress Strain ◽  
Strain Data

Abstract Unidirectional cord-rubber specimens in the form of tensile coupons and sandwich beams were used. Using specimens with the cords oriented at 0°, 45°, and 90° to the loading direction and appropriate data reduction, we were able to obtain complete characterization for the in-plane stress-strain response of single-ply, unidirectional cord-rubber composites. All strains were measured by means of liquid mercury strain gages, for which the nonlinear strain response characteristic was obtained by calibration. Stress-strain data were obtained for the cases of both cord tension and cord compression. Materials investigated were aramid-rubber, polyester-rubber, and steel-rubber.

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