scholarly journals Analytical Models for Effective Flexural Rigidity of Concrete Segments and Joints

2017 ◽  
Author(s):  
Shouju Li ◽  
Zhiyun Wang ◽  
Yutao Li
Keyword(s):  
Flexural Rigidity ◽  
Analytical Models

Rigidity of telescopic boom equipment

2021 ◽  
Keyword(s):  
Horizontal Plane ◽  
Flexural Rigidity ◽  
Hydraulic Cylinder ◽  
Analytical Models ◽  
Dynamic Coefficient ◽  
Stiffness Coefficient ◽  
Uneven Wear

As a result of the study, analytical models of the rigidity of the telescopic boom equipment in the vertical and horizontal planes were developed, which take into account: the influence of uneven intersectional vertical and horizontal gaps, the flexibility of the sliding supports, the flexural rigidity of the sections, the rigidity of the telescoping hydraulic cylinder and the lifting hydraulic cylinder. The dynamic coefficient is determined, taking into account the presence of intersectional gaps, with unsteady movement in the vertical and horizontal plane. The influence of intersectional gaps on the coefficient of dynamism and rigidity of the boom equipment taking into account the uneven wear of the sliding supports is established. Keywords telescopic boom, railway crane, stiffness coefficient, dynamic coefficient

Shear in Flexure of Fiber Composites with Different End Supports

2003 ◽  
Vol 82 (4) ◽  
pp. 262-266 ◽  
Author(s):  
K.A. Eckrote ◽  
C.J. Burstone ◽  
M.A. Freilich ◽  
G.E. Messer ◽  
A.J. Goldberg
Keyword(s):  
Flexural Rigidity ◽  
Fiber Composites ◽  
Experimental Results ◽  
Analytical Models ◽  
Beam Deflection ◽  
Fiber Reinforced Composite ◽  
Simply Supported ◽  
Aspect Ratios ◽  
Reinforced Composite ◽  
D Values

The integrity of fiber-reinforced composite (FRC) prostheses is dependent, in part, on flexural rigidity. The object of this study was to determine if the flexure behavior of uniform FRC beams with restrained or simply supported ends and various length/depth (L/d) aspect ratios could be more accurately modeled by correcting for shear. Experimental results were compared with three analytical models. All models were accurate at high L/d ratios, but the shear-corrected model was accurate to the lowest, more clinically relevant, L/d values. In this range, more than 40% of the beam deflection was due to shear.

The influence of strain history and strain gradient on confined concrete

1987 ◽  
Vol 14 (3) ◽  
pp. 336-341
Author(s):  
U. Ersoy ◽  
A. T. Tankut ◽  
M. Uzumeri
Keyword(s):  
Reinforced Concrete ◽  
Strain Gradient ◽  
Flexural Rigidity ◽  
Confined Concrete ◽  
Analytical Models ◽  
Repeated Loading ◽  
Strain History ◽  
Test Results ◽  
Ultimate Capacity ◽  
Concrete Confinement

This paper outlines the results of tests performed to study the effect of strain gradient, strain history, and initial precracking on the efficiency of confinement in reinforced-concrete columns. To this end, five reinforced-concrete specimens with closely spaced ties have been tested under combined flexure and axial load.Two of the specimens were used as control specimens, subjected only to a strain gradient. The remaining three specimens were precracked using different loading schemes and then tested under a combination of flexure and axial load. Two of these specimens were tested with repeated loading.The test results revealed that precracking lowered both the flexural rigidity and the ultimate capacity of the specimens. No significant differences were observed due to the type of loading used to initially crack the specimens. Repetition of loading did not seem to affect the ultimate capacity of the specimens.Comparison of the test results with four analytical models for confined concrete showed that the models that predicted the behaviour of the control specimens accurately, overestimated the capacities of the precracked specimens. The Thompson and Park concrete model accurately predicted the behaviour of the specimens tested with repeated loading. Key words: reinforced concrete, confined concrete, confinement, columns, cyclic loading, precracked column, experimental.

Mechanism of irregular crack-propagation in thermal controlled fracture of ceramics induced by microwave

2020 ◽  
Vol 21 (6) ◽  
pp. 610
Author(s):  
Xiaoliang Cheng ◽  
Chunyang Zhao ◽  
Hailong Wang ◽  
Yang Wang ◽  
Zhenlong Wang
Keyword(s):  
Crack Propagation ◽  
Industrial Application ◽  
Ceramic Materials ◽  
Advanced Technology ◽  
Analytical Models ◽  
Propagation Mechanism ◽  
Unstable Crack ◽  
Fracture Simulation ◽  
Initial Stage ◽  
Controlled Fracture

Microwave cutting glass and ceramics based on thermal controlled fracture method has gained much attention recently for its advantages in lower energy-consumption and higher efficiency than conventional processing method. However, the irregular crack-propagation is problematic in this procedure, which hinders the industrial application of this advanced technology. In this study, the irregular crack-propagation is summarized as the unstable propagation in the initial stage, the deviated propagation in the middle stage, and the non-penetrating propagation in the end segment based on experimental work. Method for predicting the unstable propagation in the initial stage has been developed by combining analytical models with thermal-fracture simulation. Experimental results show good agreement with the prediction results, and the relative deviation between them can be <5% in cutting of some ceramics. The mechanism of deviated propagation and the non-penetrating propagation have been revealed by simulation and theoretical analysis. Since this study provides effective methods to predict unstable crack-propagation in the initial stage and understand the irregular propagation mechanism in the whole crack-propagation stage in microwave cutting ceramics, it is of great significance to the industrial application of thermal controlled fracture method for cutting ceramic materials using microwave.

Classifying the Past: Discriminant Analysis and its Application to Medieval Farming Systems

1996 ◽  
Vol 8 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ken Bartley
Keyword(s):  
Cluster Analysis ◽  
Discriminant Analysis ◽  
Processing Time ◽  
Farming Systems ◽  
Frame Of Reference ◽  
Analytical Models ◽  
Successful Implementation ◽  
Medieval Period ◽  
The Past ◽  
Livestock Management

This paper discusses the need for nationally based analytical models of the medieval period. The use of cluster analysis as a method for classifying demesne farms, by the crops they grew and their livestock management, is explained. Successful implementation of cluster analysis requires both the existence of a large base sample, to permit isolation of specific groupings within the data, and access to considerable processing time. The paper concludes by demonstrating how discriminant analysis can provide an efficient and systematic way of classifying even a single manor within a national frame of reference.

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.

Investigations of Road Wear Caused by Studded Tires

2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies
Keyword(s):  
Traffic Safety ◽  
Test Bench ◽  
Operating Conditions ◽  
Test Method ◽  
Analytical Models ◽  
The Road ◽  
Driving Speed ◽  
Major Factors ◽  
Tire Friction ◽  
Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

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.

Carbonate Rock Physics: Analytical Models and Validations Using Computational Approaches and Lab/Log Measurements

2007 ◽  
Author(s):  
Shiyu Xu ◽  
Ganglin Chen ◽  
Yaping Zhu ◽  
Jie Zhang ◽  
Michael Payne ◽  
...  
Keyword(s):  
Carbonate Rock ◽  
Rock Physics ◽  
Analytical Models ◽  
Computational Approaches
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