scholarly journals The Mechanical Fracture of a Railway Bogie under Cyclic Loading by Ansys

2015 ◽  
Vol 28 ◽  
pp. 03002 ◽  
Author(s):  
Redouan Zellagui ◽  
Ahmed Bellaouar ◽  
Mohammed Lachi
Keyword(s):  
Cyclic Loading ◽  
Mechanical Fracture ◽  
Railway Bogie

Fracture and Fatigue Crack Propagation in Graded Composites

2005 ◽  
Vol 492-493 ◽  
pp. 573-580 ◽  
Author(s):  
Matthew Tilbrook ◽  
Lyndal Rutgers ◽  
Robert J. Moon ◽  
Mark Hoffman
Keyword(s):  
Cyclic Loading ◽  
Crack Propagation ◽  
Crack Growth ◽  
Crack Extension ◽  
Element Model ◽  
Crack Growth Resistance ◽  
Fatigue Properties ◽  
Mechanical Fracture ◽  
Propagation Resistance ◽  
Crack Propagation Resistance

The propagation of cracks in graded materials under monotonic and cyclic loading was investigated via experiment and simulation. Graded alumina/epoxy composite specimens exhibiting a variation in composition from 5% to 65% epoxy, representing a twenty-fold variation in Young’s modulus, across a region of width between 6 and 20 mm, were produced by a multistep infiltration technique. Crack initiation and propagation under monotonic and cyclic four-point bend loading was monitored and crack trajectories and growth rates were measured. Initial crack deflection was observed, in agreement with theoretical and computational predictions in the literature. Cracks exhibited further deviation as they traversed the graded region. Higher deflection angles were observed for specimens with steeper gradients, and for those with cracks initially located closer to the compliant side of the gradient. Homogeneous specimens in the composition range 5% to 55% epoxy were also produced to investigate the composition dependence of mechanical, fracture and fatigue properties for aluminaepoxy composites. Crack propagation resistance appeared to differ between monotonic and cyclic loading, though an increase with crack extension was observed in both cases. The significant variation in measured crack-propagation resistance, for cracks in graded specimens, was accordingly interpreted as a combination of crack-extension effect and spatial variation of both intrinsic and extrinsic crack-growth resistance. A finite element model has been developed to simulate the propagation process, with particular attention paid to crack propagation and deflection criteria. Results from homogeneous specimens were utilised for estimating spatial property distribution and crack-extension effects in the graded specimens. Experimental results for crack path and crack-growth resistance profile show good agreement with modeling predictions.

scholarly journals Headless Screw Fixation of Metacarpal Neck Fractures: A Mechanical Comparative Analysis

Hand ◽  
2017 ◽  
Vol 14 (2) ◽  
pp. 187-192 ◽  
Author(s):  
Christopher M. Jones ◽  
Eric M. Padegimas ◽  
Nicole Weikert ◽  
Samuel Greulich ◽  
Asif M. Ilyas ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Fracture Fixation ◽  
Kirschner Wire ◽  
Testing Machine ◽  
Fourth Generation ◽  
Mechanical Fracture ◽  
Fixation Methods ◽  
Load To Failure ◽  
Neck Fracture ◽  
Material Testing Machine

Background: The purpose of this study was to compare the mechanical properties of metacarpal neck fracture fixation by headless compression screw (HCS) with that of Kirschner wire (KW) cross-pinning and locking plate (LP) fixation. Methods: A metacarpal neck fracture was created in 30 fourth-generation composite Sawbones metacarpal models. A volar-based wedge was removed using a custom jig to simulate a typical apex dorsal fracture, unstable in flexion. The models were divided into 3 equal groups based on the method of fixation: retrograde cross-pinning with two 1.2-mm KWs, 2.0-mm dorsal T-plate with six 2.0-mm locking screws (LP), and a 3.0-mm retrograde HCS. Models were fixed at the proximal end, mounted in a material testing machine, and loaded through a cable tensioned over the metacarpal head, simulating grip loading. Cyclic loading from 0 to 40 N was performed, followed by loading to failure. Load, displacement, and failure mode were recorded. Results: Stiffness of the HCS (7.3 ± 0.7 N/m) was significantly greater than the KW (5.8 ± 0.5 N/m) but significantly less than the LP (9.5 ± 1.9 N/m). With cyclic loading to 40 N, the LP exhibited significantly less displacement (0.2 ± 1.3 mm) compared with the HCS (2.5 ± 2.3 mm) and KW (2.8 ± 1.0 mm). Load to failure for the HCS (215.5 ±3 9.0 N) was lower than that of the KW (279.7 ± 100.3 N) and of the LP (267.9 ± 44.1 N), but these differences were not statistically significant. Conclusions: The HCS provided mechanical fracture fixation properties comparable with KW fixation. The LP construct allowed significantly less displacement and had the highest strength of the 3 fixation methods.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

On The Dynamic Behaviour of Automobile Pulleys Under Cyclic Loading

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Haval Kamal Asker ◽  
Thaker Saleh Dawood
Keyword(s):  
Cyclic Loading ◽  
Dynamic Behaviour

Evaluation of System Effectiveness of Multifunctional Hydrogen Complex at Nuclear Power Plants

2019 ◽  
pp. 24-39
Author(s):  
R. Z. Aminov ◽  
A. N. Bayramov ◽  
M. V. Garievskii
Keyword(s):  
Cyclic Loading ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Frequency Control ◽  
Economic Effect ◽  
Current Frequency ◽  
Main Equipment ◽  
Primary Frequency ◽  
Primary Frequency Control

The paper gives the analysis of the problem of the primary current frequency regulation in the power system, as well as the basic requirements for NPP power units under the conditions of involvement in the primary regulation. According to these requirements, the operation of NPPs is associated with unloading and a corresponding decrease in efficiency. In this regard, the combination of nuclear power plants with a hydrogen complex is shown to eliminate the inefficient discharge mode which allows the steam turbine equipment and equipment of the reactor facility to operate in the basic mode at the nominal power level. In addition, conditions are created for the generation and accumulation of hydrogen and oxygen during the day, as well as additionally during the nighttime failure of the electrical load which allows them to be used to generate peak power.  The purpose of the article is to assess the systemic economic effect as a result of the participation of nuclear power plants in combination with the hydrogen complex in the primary control of the current frequency in the power sys-tem, taking into account the resource costs of the main equipment. In this regard, the paper gives the justification of cyclic loading of the main equipment of the hydrogen complex: metal storage tanks of hydrogen and oxygen, compressor units, hydrogen-oxygen combustion chamber of vapor-hydrogen overheating of the working fluid in the steam turbine cycle of a nuclear power plant. The methodological foundations for evaluating the working life of equipment under cyclic loading with the participation in the primary frequency control by the criterion of the growth rate of a fatigue crack are described. For the equipment of the hydrogen complex, the highest intensity of loading is shown to occur in the hydrogen-oxygen combustion chamber due to high thermal stresses.  The system economic effect is estimated and the effect of wear of the main equipment under cyclic loading is shown. Under the conditions of combining NPP power units with a hydrogen complex, the efficiency of primary reg-ulation is shown to depend significantly on: the cost of equipment subjected to cyclic loading; frequency and intensity of cyclic loading; the ratio of the tariff for peak electricity, and the cost of electricity of nuclear power plants.  Based on the developed methodology for assessing the effectiveness of the participation of nuclear power plants with a hydrogen complex in the primary frequency control, taking into account the damage to the equipment, the use of the hydrogen complex is shown to provide a tangible economic effect compared with the option of unloading nuclear power plants with direct participation in frequency control.

Behavior of HPFRC Connections for Precast Concrete Frames Under Reversed Cyclic Loading

PCI Journal ◽  
1998 ◽  
Vol 43 (6) ◽  
pp. 58-71 ◽  
Author(s):  
Rosa M. Vasconez ◽  
Antoine E. Naaman ◽  
James K. Wight
Keyword(s):  
Cyclic Loading ◽  
Precast Concrete ◽  
Concrete Frames ◽  
Reversed Cyclic Loading ◽  
Reversed Cyclic

Effect of Structural Anisotropy on Deformation Properties of Granite under Cyclic Loading.

1997 ◽  
Vol 46 (9) ◽  
pp. 1029-1034 ◽  
Author(s):  
Harushige KUSUMI ◽  
Yukihisa MINE ◽  
Kazuhiko NISHIDA
Keyword(s):  
Cyclic Loading ◽  
Structural Anisotropy ◽  
Deformation Properties
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