ELASTIC SHEAR STIFFNESS OF COLUMNS WITH WING WALLS AND BEAMS WITH SPANDREL WALLS

2020 ◽  
Vol 85 (769) ◽  
pp. 367-372
Author(s):  
Susumu TAKAHASHI
Keyword(s):  
Shear Stiffness ◽  
Wing Walls ◽  
Elastic Shear

scholarly journals Effective elastic shear stiffness of a periodic fibrous composite with non-uniform imperfect contact between the matrix and the fibers

2014 ◽  
Vol 51 (6) ◽  
pp. 1253-1262 ◽  
Author(s):  
Juan C. López-Realpozo ◽  
Reinaldo Rodríguez-Ramos ◽  
Raúl Guinovart-Díaz ◽  
Julián Bravo-Castillero ◽  
J.A. Otero ◽  
...  
Keyword(s):  
Fibrous Composite ◽  
Shear Stiffness ◽  
Imperfect Contact ◽  
The Matrix ◽  
Elastic Shear

Consolequip Steering Bogie for the Société Nationale Industrielle et Minière ‘SNIM’ de la Mauritanie

2000 ◽  
Author(s):  
Varoujan Khatchadourian
Keyword(s):  
Dynamic Response ◽  
Shear Stiffness ◽  
Design Engineering ◽  
Unique Combination ◽  
Heavy Duty ◽  
Wheel Wear ◽  
Damping Characteristics ◽  
Stiffness Characteristics ◽  
Hunting Stability ◽  
Elastic Shear

Abstract This paper describes in detail the design, engineering and testing conducted for 260 self-steering bogies in response to a bid from SNIM (Société Nationale Industrielle et Minière), in Mauritania, Africa. Severe environmental conditions in Mauritania, caused by the presence of sand, contribute to accelerated wheel tread wear. This in combination with asymmetric wheel wear typically experienced with the standard three-piece bogie, results in poor wheel life. A steering bogie improves wheel life by allowing the axles to self-align, thus reducing asymmetric wheel wear occurrence. Bogie behavior is explained by comparing the stiffness characteristics of self-steering bogies and standard three-piece bogies. High bogie stiffness keeps a truck square as it travels on the track, thus improving its dynamic response on tangent track. Split type friction wedges are used together with heavy-duty suspension system to obtain high bogie shear stiffness and vertical damping characteristics. An elastic shear pad between the roller bearings and the side frame pedestal roof allows the axles to self-align in curves, giving the truck its self-steering characteristic. The truck design is unique as the standard AAR unit guide bracket construction point and angle were changed to provide the alignment for the unique combination of axle spacing and wheel diameter. It utilizes 1000 mm diameter wheels and a wheel base of 1800 mm. The Consolequip steering bogie has been engineered to improve dynamic response on tangent track. This is done by increasing bogie interaxle shear stiffness which increases the threshold of truck hunting. Stability tests with service worn wheels confirmed stability speed to exceed operating speeds used by SNIM network. Preliminary projections have estimated an improvement of up to 50% in wheel life by reducing asymmetric wheel wear and the number of times they are re-profiled.

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.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

scholarly journals Nonlinear modelling of the seismic response of masonry structures: Calibration strategies

2021 ◽  
Author(s):  
Antonio Maria D’Altri ◽  
Francesco Cannizzaro ◽  
Massimo Petracca ◽  
Diego Alejandro Talledo
Keyword(s):  
Mechanical Properties ◽  
Numerical Models ◽  
Shear Stiffness ◽  
Model Material ◽  
National Standards ◽  
National Standard ◽  
Masonry Structures ◽  
Nonlinear Modelling ◽  
Various Boundary Conditions ◽  
Panel Stiffness

AbstractIn this paper, a simple and practitioners-friendly calibration strategy to consistently link target panel-scale mechanical properties (that can be found in national standards) to model material-scale mechanical properties is presented. Simple masonry panel geometries, with various boundary conditions, are utilized to test numerical models and calibrate their mechanical properties. The calibration is successfully conducted through five different numerical models (most of them available in commercial software packages) suitable for nonlinear modelling of masonry structures, using nonlinear static analyses. Firstly, the panel stiffness calibration is performed, focusing the attention to the shear stiffness. Secondly, the panel strength calibration is conducted for several axial load ratios by attempts using as reference the target panel strength deduced by well-known analytical strength criteria. The results in terms of panel strength for the five different models show that this calibration strategy appears effective in obtaining model properties coherent with Italian National Standard and Eurocode. Open issues remain for the calibration of the post-peak response of masonry panels, which still appears highly conventional in the standards.

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