Evolution of Crack Aspect Ratio in Sheets Under Tension and Bending Cyclic Loading

The applicability of GLARE is restricted due to the frequent delamination of different materials at interlaminar. The previous researches showed that the major parameter to control the delamination of GLARE was a crack (a). On the other hand, it was also shown that a delamination width (b) could strongly effect on the delamination behavior. Therefore, the aim of this research is to define the delamination behavior using the above correlation. In conclusions, it was shown that the delamination aspect ratio (b/a) was slowly decreased and the delamination area rate (ADR) was increased as the normalized crack size (a/W) was increased. The effect of the delamination shape was strong at the beginning of the cyclic loading but it was gradually diminished.

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Analysis of Cyclic Response of Bucket Foundations Based on Simplified Kinematic Hardening Model

Advances in Civil Engineering ◽

10.1155/2020/9324935 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Qing-lai Fan ◽

Guo-feng Xiao ◽

Xiao-di Chen

Keyword(s):

Finite Element ◽

Cyclic Loading ◽

Aspect Ratio ◽

Kinematic Hardening ◽

Interface Condition ◽

Offshore Wind ◽

Combined Loading ◽

In Situ Tests ◽

Aspect Ratios

The response of bucket foundations for offshore wind turbines subjected to cyclic loading in saturated clay is explored through three-dimensional finite element numerical analyses. In the analyses, nonlinear cyclic hysteretic behavior of clay under undrained condition is modeled through a simple kinematic hardening constitutive model embedded in ABAQUS. The finite element model is validated against published in situ tests of bucket foundations under quasistatic cyclic loading in Bothkennar clay. The computed results agreed generally with those from in situ tests. The behavior of bucket foundations with different aspect ratios under displacement-controlled cyclic loading mode is investigated. Then, the evolution of foundation displacement with increasing number of cycles is studied subjected to wind and wave combined loading. The results show that, for the cycles of low-amplitude rotation, dimensionless moment-rotation curve is approximately elastic; however, the curve engenders obvious hysteresis loop, whose shape is influenced by soil-sidewall interface condition, during high-amplitude cycles. Under thousands of loading cycles, for bucket foundations of low aspect ratio, the oscillatory displacement component is smaller; however, the residual component will accumulate gradually until the serviceability rotation is exceeded. For foundations of high aspect ratio, the oscillatory component is relatively larger, but the accumulation rate of residual displacement decreases gradually.

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Perceptual and Emotional Responses as a Function of Film Aspect Ratio as Viewed on a Television Screen

PsycEXTRA Dataset ◽

10.1037/e413782005-390 ◽

1999 ◽

Author(s):

Norman G. Gordon ◽

Michael J. Johnson

Keyword(s):

Aspect Ratio ◽

Emotional Responses ◽

Television Screen

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

Mechanics & Industry ◽

10.1051/meca/2020061 ◽

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.

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Modification of MnS inclusion by tellurium in 38MnVS6 micro-alloyed steel

Metallurgical Research & Technology ◽

10.1051/metal/2020066 ◽

2020 ◽

Vol 117 (6) ◽

pp. 615

Author(s):

Ping Shen ◽

Lei Zhou ◽

Qiankun Yang ◽

Zhiqi Zeng ◽

Kenan Ai ◽

...

Keyword(s):

Fatigue Life ◽

Aspect Ratio ◽

Strong Influence ◽

Experimental Results ◽

Alloyed Steel ◽

Equivalent Diameter ◽

Small Aspect Ratio ◽

Steel Quality ◽

Eds Analysis ◽

Micro Alloyed Steel

In 38MnVS6 steel, the morphology of sulfide inclusion has a strong influence on the fatigue life and machinability of the steel. In most cases, the MnS inclusions show strip morphology after rolling, which significantly affects the steel quality. Usually, the MnS inclusion with a spherical morphology is the best morphology for the steel quality. In the present work, tellurium was applied to 38MnVS6 micro-alloyed steel to control the MnS inclusion. Trace tellurium was added into 38MnVS6 steel and the effect of Te on the morphology, composition, size and distribution of MnS inclusions were investigated. Experimental results show that with the increase of Te content, the equivalent diameter and the aspect ratio of inclusion decrease strikingly, and the number of inclusions with small aspect ratio increases. The inclusions are dissociated and spherized. The SEM-EDS analysis indicates that the trace Te mainly dissolves in MnS inclusion. Once the MnS is saturated with Te, MnTe starts to generate and wraps MnS. The critical Te/S value for the formation of MnTe in the 38MnV6 steel is determined to be approximately 0.075. With the increase of Te/S ratio, the aspect ratio of MnS inclusion decreases and gradually reaches a constant level. The Te/S value in the 38MnVS6 steel corresponding to the change of aspect ratio from decreasing to constant ranges from 0.096 to 0.255. This is most likely to be caused by the saturation of Te in the MnS inclusion. After adding Te in the steel, rod-like MnS inclusion is modified to small inclusion and the smaller the MnS inclusion, the lower the aspect ratio.

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