Effect of Stress Ratio on the Cumulative Value of Energy Dissipation

2014 ◽  
Vol 598 ◽  
pp. 125-132 ◽  
Author(s):  
Bogdan Ligaj
Keyword(s):  
Energy Dissipation ◽  
Plastic Strain ◽  
Strain Energy ◽  
Stress Ratio ◽  
Constant Amplitude ◽  
Stress Strain ◽  
Similar Nature ◽  
Plastic Strain Energy ◽  
Cumulative Plastic Strain ◽  
The Relationship

Aim of this work is to analyze the stress-strain loops recorded during the study c45 steel under programmable stress for constant amplitude loads of the stress ratio: R = -2.0, R = -1.0 and R = -0.5. The results presented in the paper of cumulative plastic strain energy show that the nature of the relationship ΣΔWpl-N for loads of different values of stress ratio R is similar. Course of changes of relationship ΣΔWpl-N for loads with R = -0.5 and R = -2.0 shows a similar nature and range of changes in the value ΣΔWpl, despite significantly different parameters of load.

Analysis of Hysteresis Loop on the Basis of Variable-Amplitude Loading

2016 ◽  
Vol 250 ◽  
pp. 94-99
Author(s):  
Bogdan Ligaj
Keyword(s):  
Plastic Strain ◽  
Hysteresis Loop ◽  
Strain Energy ◽  
Energy Parameter ◽  
Stress Strain ◽  
Variable Amplitude Loading ◽  
Loading Cycle ◽  
Variable Amplitude ◽  
Plastic Strain Energy

The aim of this paper is to present a method to be used for analysis of stress-strain loops under variable amplitude loading. The method for determination of plastic strain energy parameter ΔWpl consists in determination of envelopes around stress-strain branches (increasing and decreasing) formed in effect of application of a loading program. The method involves development of envelopes to determine energy parameter from the highest (for the highest loading cycle) to the lowest (for the lowest cycle). The paper includes results of stress-strain loop for steel C45.

Performance Evaluation of Buckling-Restrained Braces Installed in a Mid-Rise Steel Structure

2018 ◽  
Vol 763 ◽  
pp. 884-891
Author(s):  
Ryohei Narui ◽  
Kazuhisa Koyano ◽  
Mitsumasa Midorikawa ◽  
Tadao Nakagomi ◽  
Mamoru Iwata
Keyword(s):  
Plastic Strain ◽  
Seismic Performance ◽  
Strain Energy ◽  
High Performance ◽  
Steel Structure ◽  
Basic Type ◽  
Building Structure ◽  
Plastic Strain Energy ◽  
Cumulative Plastic Strain ◽  
Strain Energy Ratio

The authors have continuously studied buckling-restrained braces using steel mortar planks (BRBSM). The performance of energy absorption and fatigue against cyclic loading has been evaluated. Although past studies have clarified the structural performance of BRBSM as single member, it is necessary to study not only the performance of BRBSM as single member but also the performance of BRBSM installed in a building structure. In this paper, a frame model of mid-rise steel structure with BRBSM subjected to earthquake motions with various characteristics is analyzed. Comparing the results of the analysis and the past tests, the seismic behavior of a structure is discussed. Especially, the seismic performance of BRBSM installed in the building structure is evaluated. In addition, the seismic performance of two types of BRBSM; basic and developed high-performance types, is compared and evaluated about cumulative plastic strain energy ratio and cumulative fatigue. As a result, the performance capacities of the both types of BRBSM exceed the required values of BRBSM under severe earthquake motions about cumulative plastic strain energy ratio and cumulative fatigue. The basic-type BRBSM has the fatigue capacity against 2 to 5 times severe earthquake motions. The required values of high-performance-type BRBSM are about a half of accumulated fatigue capacity compared with the basic-type one. The high-performance-type BRBSM is applicable against quite many cyclic loadings of low strain amplitude, and able to be used for long-term service.

scholarly journals Optimum Strength Distribution for Structures with Metallic Dampers Subjected to Seismic Loading

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 127 ◽  
Author(s):  
Jesús Donaire-Ávila ◽  
Amadeo Benavent-Climent
Keyword(s):  
Plastic Strain ◽  
Shear Force ◽  
Strain Energy ◽  
Strength Distribution ◽  
Force Coefficient ◽  
Optimum Yield ◽  
Lateral Strength ◽  
Metallic Dampers ◽  
Plastic Strain Energy ◽  
Cumulative Plastic Strain

A key aspect of the seismic design of structures is the distribution of the lateral strength, because it governs the distribution of the cumulative plastic strain energy (i.e., the damage) among the stories. The lateral shear strength of a story i is commonly normalized by the upward weight of the building and expressed by a shear force coefficient αi. The cumulative plastic strain energy in a given story i can be normalized by the product of its lateral strength and yield displacement, and expressed by a plastic deformation ratio ηi. The distribution αi/α1 that makes ηi equal in all stories is called the optimum yield-shear force distribution. It constitutes a major aim of design; a second aim is to achieve similar ductility demand in all stories. This paper proposes a new approach for deriving the optimum yield-shear force coefficient distribution of structures without underground stories and equipped with metallic dampers. It is shown, both numerically and experimentally, that structures designed with the proposed distribution fulfil the expected response in terms of both damage distribution and inter-story drift demand. Moreover, a comparison with other distributions described in the literature serves to underscore the advantages of the proposed approach.

An analysis based on plastic strain energy for bilinearity in Coffin-Manson plots in an AlLi alloy

1994 ◽  
Vol 30 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
N.Eswara Prasad ◽  
A.G. Paradkar ◽  
G. Malakondaiah ◽  
V.V. Kutumbarao
Keyword(s):  
Plastic Strain ◽  
Strain Energy ◽  
Plastic Strain Energy

scholarly journals Experimental Research on Deformation Characteristics of Using Silty Clay Modified Oil Shale Ash and Fly Ash as the Subgrade Material after Freeze-Thaw Cycles

2019 ◽  
Vol 11 (18) ◽  
pp. 5141 ◽  
Author(s):  
Wei ◽  
Li ◽  
Han ◽  
Han ◽  
Wang ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Stress Ratio ◽  
Dynamic Stress ◽  
Confining Pressure ◽  
Silty Clay ◽  
Loading Frequency ◽  
Axial Deformation ◽  
Cumulative Strain ◽  
Cumulative Plastic Strain ◽  
Shale Ash

To achieve the purposes of disposing industry solid wastes and enhancing the sustainability of subgrade life-cycle service performance in seasonally frozen regions compared to previous research of modified silty clay (MSC) composed of oil shale ash (OSA), fly ash (FA), and silty clay (SC), we identified for the first time the axial deformation characteristics of MSC with different levels of cycle load number, dynamic stress ratio, confining pressure, loading frequency, and F-T cycles; and corresponding to the above conditions, the normalized and logarithmic models on the plastic cumulative strain prediction of MSC are established. For the effect of cycle load number, results show that the cumulative plastic strain of MSC after 1, 10, and 100 cycle loads occupies for 28.72%~35.31%, 49.86%~55.59%, and 70.87%~78.39% of those after 8000 cycle loads, indicating that MSC possesses remarkable plastic stability after 100 cycles of cycle loads. For the effect of dynamic stress ratio, confining pressure, loading frequency, and F-T cycles, results show that dynamic stress ratio and F-T cycles are important factors affecting the axial deformation of MSC after repeated cycle loads; and under the low dynamic stress ratio, increasing confining pressure and loading frequency have insignificant effect on the axial strain of MSC after 8000 loads. In term of the normalized and logarithmic models on the plastic cumulative strain prediction of MSC, they have a high correlation coefficient with testing data, and according to the above models, the predicted result shows that the cumulative plastic strain of MSC ranges from 0.38 cm to 2.71 cm, and these predicted values are within the requirements in the related standards of highway subgrades and railway, indicating that the cumulative plastic strain of MSC is small and MSC is suitable to be used as the subgrade materials.

Plastic Strain Energy Model for Rock Salt Under Fatigue Loading

2018 ◽  
Vol 31 (3) ◽  
pp. 322-331 ◽  
Author(s):  
M. M. He ◽  
N. Li ◽  
B. Q. Huang ◽  
C. H. Zhu ◽  
Y. S. Chen
Keyword(s):  
Plastic Strain ◽  
Rock Salt ◽  
Strain Energy ◽  
Fatigue Loading ◽  
Energy Model ◽  
Plastic Strain Energy

Influence of Elastic-Plastic Bending on the Relationship Between Applied Load and Maximum Bending Stress for Straight and Curved Bars

2020 ◽  
Author(s):  
Don Metzger
Keyword(s):  
Plastic Strain ◽  
Plastic Zone ◽  
Yield Point ◽  
Cross Section ◽  
Applied Load ◽  
Bending Stress ◽  
Stress Strain ◽  
Bending Load ◽  
Bending Capacity ◽  
The Relationship

Abstract Bending capacity in excess of the load required to cause yielding is due to a combination of work hardening and the effect of the plastic zone spreading toward the neutral axis. For materials of sufficiently high ductility, a fully developed plastic zone is achieved and the bulk of the section is stressed beyond yield. For lower ductility materials, failure may occur prior to full development of the plastic zone such that only a fraction of the cross section is at or above the yield stress. In such cases, the relationship between applied load and maximum bending stress becomes sensitive to the shape of the stress-strain curve near the yield point. This relationship is examined for straight and curved bars of rectangular and trapezoidal cross-section for tensile stress-strain curves characterized by nonlinear functions. The stress distribution as a function of applied load is determined analytically by enforcing moment equilibrium across the section. The strain distribution is determined through the classical condition of “planes remain plane” during deformation. The solutions provide analytically smooth load curves such that maximum stress can be directly plotted as a function of applied load. These plots exhibit three distinct regimes of response: 1) elastic, 2) development of plastic zone, and 3) fully developed plastic zone. Since the response is analytically smooth, the detailed relationship through the knee of the tensile curve can be examined. The results indicate that bending capacity is influenced significantly by the development of small amounts of plastic strain prior to reaching a yield point defined by the usual 0.2% plastic strain offset method. The results also show how loss of ductility with respect to tensile elongation translates into reduced bending load capacity in a non-linear relationship.

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