Static and cyclic stress distributions in a buckling shear panel

1969 ◽  
Vol 4 (4) ◽  
pp. 278-284 ◽  
Author(s):  
R J Frost ◽  
P P Benham
Keyword(s):  
Stress Ratio ◽  
Cyclic Stress ◽  
Shear Loading ◽  
Stress Conditions ◽  
Accurate Assessment ◽  
Stress Distributions ◽  
Cyclic Shear ◽  
Shear Panel ◽  
Assessment Of Stress ◽  
Static Shear

A panel comprising a thin, square, flat plate of clad copper-aluminium alloy to specification B.S.2L.73, bounded by substantial edge members, was subjected to a range of static shear loadings up to a shear-stress ratio of 3·0. The experimentally determined distributions of strains and stresses within the plate reveal the importance of the stresses due to bending resulting from the formation of diagonal shear buckles. Fair agreement between the results of this study and the work of other investigators was obtained. The work presented is part of an investigation into the fatigue-crack propagation behaviour and residual-strength characteristics of flat panels subjected to shear loading, hence an accurate assessment of stress conditions at least along the two diagonals was required. The strains within the plate when subjected to a range of cyclic shear loadings were determined and a relation between cyclic strains and corresponding static strains was obtained. The use of this relation leads to a simple assessment of stress conditions within the plate due to any magnitude of cyclic shear loading.

Experimental Study on Strength Weakening of Silty Soil of Subaqueous Yellow River Delta Under Cyclic Loadings

2010 ◽  
Author(s):  
Huixin Liu ◽  
Guohui Xu ◽  
Qingpeng Zhao ◽  
Xin Wang ◽  
Yueqian Yu
Keyword(s):  
Stress Ratio ◽  
Yellow River ◽  
Yellow River Delta ◽  
Cyclic Stress ◽  
River Delta ◽  
Engineering Structures ◽  
Cyclic Stress Ratio ◽  
Cyclic Shear ◽  
Silty Soil ◽  
Critical Cyclic Stress Ratio

Silty soil seabed of Yellow River Delta is prone to sliding and liquefaction, which usually leads to geological hazards including landslides of seabed and failures of marine structures. The failure of silty soil is closely correlated with its strength change induced by wave actions. In this paper, silty soil samples of various clay contents were prepared, and cyclic triaxial experiments modeling wave actions were carried out on the samples to study the relationship between cyclic shear stress and number of cycles of silty soil taken from Subaqueous Yellow River Delta. Research results indicated that there existed a critical value in the cyclic stress exerting on the soil; the cyclic stress could cause failure of soil only when it’s value was higher than that of the critical stress; in this paper, critical cyclic stress ratio was defined as Kcr = ((σd+σ1)/σ3)cr, where Kcr is critical cyclic stress ratio, σd is axial pressure, σ1 is cyclic stress, σ3 is confining pressure. For the sake of the safety of design and construction of marine engineering structures, 1.30 was taken as the critical cyclic stress ratio of remolded silty soil in the Yellow River Delta, and 1.40 as that of the undisturbed silty soil. Also the results show that the dynamic strength weakening of silty soil followed the rule of power function attenuation. In addition, cyclic loading vibration experiments in a soil tank were carried out to study the weakening law of shear strength and penetration resistance with the variation of oscillation times.

Behaviour of Marine Clay Under Wave Type of Cyclic Loading

2003 ◽  
Author(s):  
S. Narasimha Rao ◽  
G. Gerald Moses
Keyword(s):  
Cyclic Loading ◽  
Deformation Behaviour ◽  
Cyclic Stress ◽  
Shear Loading ◽  
Load Level ◽  
Marine Clay ◽  
Cyclic Shear ◽  
Coastal Marine ◽  
Storm Wave ◽  
Stress Ratios

This paper presents the results of two series of cyclic triaxial shear tests carried out under both uniform and Varied cyclic shear loading and these bring out the influence of load cycles on strain and undrained strength of a cemented marine clay from East coast of India. The undrained shear strength and deformation behaviour of Indian coastal marine clay have been established through a detailed shear testing carried out. In order to estimate the effect brought in by varied cyclic loading, it becomes necessary to conduct reference standard tests under uniform cyclic loading at various cyclic stress ratios (CSR) on identical soil specimens and these stress levels are chosen in such a way that there is no failure taking place during testing. In field situations, storm wave loading is considered to be irregular cyclic loading in which there is a continuous variation in the load level from one cycle to the other. The results obtained from tests under uniform cyclic loading are compared with the results obtained from tests under varied cyclic loading.

Cyclic loading response of loose air-pluviated Fraser River sand for validation of numerical models simulating centrifuge tests

2005 ◽  
Vol 42 (2) ◽  
pp. 550-561 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Somasundaram Sriskandakumar ◽  
Peter Byrne
Keyword(s):  
Cyclic Loading ◽  
Simple Shear ◽  
Mechanical Response ◽  
Shear Loading ◽  
Shear Stresses ◽  
Fraser River ◽  
River Sand ◽  
Cyclic Shear ◽  
Direct Simple Shear ◽  
Static Shear

Cyclic loading response of loose Fraser River sand was investigated, as input to numerical simulation of centrifuge physical models, using constant-volume direct simple shear tests conducted with and without initial static shear stress condition. Although the observed trends in mechanical response were similar, air-pluviated specimens were more susceptible to liquefaction under cyclic loading than their water-pluviated counterparts. Densification due to increasing confining stress (stress densification) significantly increased the cyclic resistance of loose air-pluviated sand, with strong implications for the interpretation of observations from centrifuge testing. The stress densification effect, however, was not prominent in the case of water-pluviated specimens. The differences arising from the two specimen reconstitution methods can be attributed to the differences in particle structure and highlight the importance of fabric effects in the assessment of the mechanical response of sands. The initial static shear stresses appear to reduce the cyclic shear resistance of loose air-pluviated sand in simple shear loading, in contrast to the increases in resistance reported on the basis of data from triaxial testing. Data from laboratory element tests that closely mimic the soil fabric and loading modes of the centrifuge specimens are essential for meaningful validation of numerical models.Key words: liquefaction of sands, air-pluviation, cyclic loading, direct simple shear testing, specimen preparation, fabric.

The Study of the Influence of Different Drained Conditions for Seabed Stability Under Wave Loading

2009 ◽  
Author(s):  
Lien-Kwei Chien ◽  
Chi-Ling Yang ◽  
Wen-Chien Tseng
Keyword(s):  
Stress Ratio ◽  
Wave Theory ◽  
Cyclic Stress ◽  
Wave Action ◽  
Engineering Practice ◽  
Wave Loading ◽  
Cyclic Stress Ratio ◽  
Cyclic Shear ◽  
Sea Bed ◽  
Seabed Soil

A series of partial drained dynamic triaxial test were performed to understand the seabed stability under wave induced wave loading. In order to evaluate the real behavior of the strength of sea bed soil under wave action, the field sands in Kinhu were adopted in the study. The specimens were prepared by multi-pluviation through water method to simulate the particle aggregation in-situ. The marine soils stress states were simulated by Ko consolidation in laboratory. Moreover, the stability of marine sands is discussed under different drained conditions by using flow valve to control the soil drained states. In this study, the typhoon waves induced loading were simulated in small amplitude wave and Stoke’s 2nd order wave theory to evaluate the cyclic stress ratio in sea bed. From the test results found that the marine soil was liquefaction immediately by using the Stoke’s 2nd order theory. The drained efficiency is defined in this study. The relationship between strain, cyclic numbers, and cyclic stress ratio (CSR) were discussed under different drained efficiency conditions. Under the drained efficiency is 86% and the number cycle is one, the double amplitude strain (DA) of seabed soil will induce 10% by Stoke’s 2nd order wave theory induced the cyclic shear stress ratio. But under the drained efficiency is 100%, the DA of seabed soil will only induce 7%. Combined with the time concept of wave action, when the seabed soil reach to DA = 10% under wave loading, the time of wave action request 1296 sec. From the results indicated that the drained efficiency have significantly influence on deformation resistance of sea bed soil. Therefore, the study analysis could be provided the reference for near shore structure design and engineering practice, and reduce storm induced damages.

Horizontal Connections for Precast Concrete Shear Wall Panels Under Cyclic Shear Loading

PCI Journal ◽  
1996 ◽  
Vol 41 (3) ◽  
pp. 64-80 ◽  
Author(s):  
Khaled A. Soudki ◽  
Jeffrey S. West ◽  
Sami H. Rizkalla ◽  
Bruce Blackett
Keyword(s):  
Precast Concrete ◽  
Shear Wall ◽  
Shear Loading ◽  
Cyclic Shear ◽  
Horizontal Connections ◽  
Wall Panels

Application of the R-Curve Concept to Fatigue Crack Growth

1978 ◽  
Vol 100 (4) ◽  
pp. 416-420 ◽  
Author(s):  
D. P. Wilhem ◽  
M. M. Ratwani
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Extension ◽  
Stress Ratio ◽  
Cyclic Stress ◽  
Crack Growth Resistance ◽  
Resistance Curve ◽  
Cyclic Stress Ratio ◽  
Wide Range

Crack growth resistance for both static (rising load) and for cyclic fatigue crack growth has been shown to be a continuous function over a range of 0.1 μm to 10 cm in crack extension for 2024-T3 aluminum. Crack growth resistance to each fatigue cycle of crack extension is shown to approach the materials ordinary undirectional static crack resistance value when the cyclic stress ratio is zero. The fatigue crack extension is averaged over many cycles and is correlated with the maximum value of the crack tip stress intensity, Kmax. A linear plot of crack growth resistance for fatigue and static loading data shows similar effects of thickness, stress ratio, and other parameters. The effect of cyclic stress ratio on crack growth resistance for 2219 aluminum indicates the magnitude of differences in resistance when plotted to a linear scale. Prediction of many of these trends is possible using one of several available crack growth data correlating techniques. It appears that a unique resistance curve, dependent on material, crack orientation, thickness, and stress/physical environment, can be developed for crack extensions as small as 0.076 μm (3 μ inches). This wide range, crack growth resistance curve is seen of immense potential for use in both fatigue and fracture studies.

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