scholarly journals Effect of Strain Rates on the Stress–Strain Behavior of FRP-Confined Pre-Damaged Concrete

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1078 ◽  
Author(s):  
Yugui Cao ◽  
Muyu Liu ◽  
Yang Zhang ◽  
Jun Hu ◽  
Shengchun Yang
Keyword(s):  
Strain Rate ◽  
Analytical Investigation ◽  
Fiber Reinforced Polymer ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior ◽  
Reinforced Polymer ◽  
Proposed Model ◽  
Concrete Damage ◽  
Strain Model

There are many studies on fiber-reinforced polymer (FRP)-confined pre-damaged concrete under quasi-static strain rates. However, few studies have focused on FRP-confined pre-damaged concrete under high strain rates. Thus, an experimental and analytical investigation was conducted to obtain the mechanical behavior of FRP-confined pre-damaged concrete under different strain rates. The results show that the stress–strain curves, ultimate stress, and strain values were affected by strain rate and the extent of concrete damage. A stress–strain model of FRP-confined pre-damaged concrete considering the strain rate was developed by modifying a stress–strain model of FRP-confined pre-damaged concrete under quasi-static loading. The proposed model was evaluated by using test data. The evaluation results show that the proposed model can predict the stress–strain behavior of FRP-confined pre-damaged concrete under different strain rates.

Novel fiber-reinforced polymer cross wrapping strengthening technique: A comparative study

2019 ◽  
Vol 23 (5) ◽  
pp. 979-996 ◽  
Author(s):  
Jun-Jie Zeng ◽  
Zhi-Jian Duan ◽  
Yong-Chang Guo ◽  
Zhi-Hong Xie ◽  
Li-Juan Li
Keyword(s):  
Comparative Study ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
The Novel ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Strain Behavior ◽  
Reinforced Polymer ◽  
Strengthening Technique ◽  
Strain Model

This article presents a comparative study on behavior of fiber-reinforced polymer–confined concrete in axially loaded circular columns strengthened using three different fiber-reinforced polymer partial wrapping strengthening schemes: the fiber-reinforced polymer ring wrapping, the fiber-reinforced polymer strip helical wrapping, and the novel fiber-reinforced polymer strip cross helical wrapping. The test results show that at an identical confinement ratio, the strength enhancement efficiency of the fiber-reinforced polymer strip helical wrapping is slightly weaker than those of the other two strengthening schemes, while the strain enhancement efficiency of the fiber-reinforced polymer strip helical wrapping is the strongest among the three strengthening schemes. An analysis-oriented stress–strain model is proposed for the confined concrete with fiber-reinforced polymer partial wrapping, and the comparisons show that the model is capable to provide satisfactory predictions on stress–strain behavior of confined concrete with fiber-reinforced polymer partial wrapping.

Understanding Dynamic Recrystallization Behavior through a Delay Differential Equation Approach

2007 ◽  
Vol 558-559 ◽  
pp. 441-448 ◽  
Author(s):  
Jong K. Lee
Keyword(s):  
Differential Equation ◽  
Strain Rate ◽  
Critical Strain ◽  
Strain Curve ◽  
Single Peak ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Behavior ◽  
Delay Differential

During hot working, deformation of metals such as copper or austenitic steels involves features of both diffusional flow and dislocation motion. As such, the true stress-true strain relationship depends on the strain rate. At low strain rates (or high temperatures), the stress-strain curve displays an oscillatory behavior with multiple peaks. As the strain rate increases (or as the temperature is reduced), the number of peaks on the stress-strain curve decreases, and at high strain rates, the stress rises to a single peak before settling at a steady-state value. It is understood that dynamic recovery is responsible for the stress-strain behavior with zero or a single peak, whereas dynamic recrystallization causes the oscillatory nature. In the past, most predictive models are based on either modified Johnson-Mehl-Avrami kinetic equations or probabilistic approaches. In this work, a delay differential equation is utilized for modeling such a stress-strain behavior. The approach takes into account for a delay time due to diffusion, which is expressed as the critical strain for nucleation for recrystallization. The solution shows that the oscillatory nature depends on the ratio of the critical strain for nucleation to the critical strain for completion for recrystallization. As the strain ratio increases, the stress-strain curve changes from a monotonic rise to a single peak, then to a multiple peak behavior. The model also predicts transient flow curves resulting from strain rate changes.

High Strain-Rate Compressive Behavior and Constitutive Modeling of Selected Polymers Using Modified Ramberg-Osgood Equation

2014 ◽  
Vol 566 ◽  
pp. 80-85
Author(s):  
Kenji Nakai ◽  
Takashi Yokoyama
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
Constitutive Modeling ◽  
High Strain ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior ◽  
Least Squares Fit ◽  
Wide Range

The present paper is concerned with constitutive modeling of the compressive stress-strain behavior of selected polymers at strain rates from 10-3 to 103/s using a modified Ramberg-Osgood equation. High strain-rate compressive stress-strain curves up to strains of nearly 0.08 for four different commercially available extruded polymers were determined on the standard split Hopkinson pressure bar (SHPB). The low and intermediate strain-rate compressive stress-strain relations were measured in an Instron testing machine. Six parameters in the modified Ramberg-Osgood equation were determined by fitting to the experimental stress-strain data using a least-squares fit. It was shown that the monotonic compressive stress-strain behavior over a wide range of strain rates can successfully be described by the modified Ramberg-Osgood constitutive model. The limitations of the model were discussed.

Analysis-Oriented Stress-Strain Model for Concrete Confined with Fiber-Reinforced Polymer Spirals

2017 ◽  
Vol 114 (5) ◽  
Author(s):  
Thomas A. Hales ◽  
Chris P. Pantelides ◽  
Priyank Sankholkar ◽  
Lawrence D. Reaveley
Keyword(s):  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Strain Model

scholarly journals Estimation of Stress-Strain behavior of polyethylene terephthalate (PET) at different strain rates by Artificial Neural Network under simultaneous stretch scenario

2021 ◽  
Author(s):  
Fei Teng ◽  
Gary Menary ◽  
Savko Malinov ◽  
Shiyong Yan
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Strain Rate ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain And Strain Rate ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
High Degree

In this paper, an Artificial Neural Network (ANN) is used to predict the stress-strain behavior of PET at conditions relevant to Stretch Blow Moulding i.e. Large equibiaxial deformation at elevated temperature and high strain rate. The input vectors considered are temperature, strain, and strain rate with a corresponding output parameter of stress. In the present work, a feed-forward back backpropagation algorithm was used to train the ANN. The ANN is able to approximate the relationship between stress and strain at various strain rates & temperatures to a high degree of accuracy for all conditions tested.

An extensive study on strain dependence of glass fiber-reinforced polymer-based composites

2021 ◽  
pp. 030932472110437
Author(s):  
Ashkan Farazin ◽  
Afrasyab Khan
Keyword(s):  
Strain Rate ◽  
Glass Fiber ◽  
Glass Fibers ◽  
Experimental Studies ◽  
Fiber Reinforced Polymer ◽  
Strain Rates ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced

Fiber-reinforced polymer-based composites may experience various strain rates under different dynamic loads. As the mechanical behavior of these composites varies with strain rate, their response will be dependent on the strain rate. This paper presents a comprehensive review on glass fibers and composites reinforced with these fibers, as the most practical polymer-based composite, under dynamic loading. First, the properties of long glass fibers under different strain rates will be reviewed in detail. In the following, experimental studies on the effects of strain rate on various types of glass fiber-reinforced polymer-based composites will be categorized and presented. The behavior of thermoset polymers will be also addressed under different strain rates. Finally, various analytical and numerical macromechanical and micromechanical models will be comprehensively described for this type of composites.

Expression of a Generic Full-Range True Stress-True Strain Model for Pipeline Steels Using the Product-Log (Omega) Function

2017 ◽  
Author(s):  
Onyekachi Ndubuaku ◽  
Michael Martens ◽  
J. J. Roger Cheng ◽  
Samer Adeeb
Keyword(s):  
True Strain ◽  
Full Range ◽  
True Stress ◽  
Stress Strain ◽  
Pipeline Steels ◽  
Strain Behavior ◽  
Proposed Model ◽  
Strain Relationship ◽  
Strain Model

Steel pipelines are subjected to a variety of complex, and sometimes difficult to predict, loading schemes during the fabrication, installation and operation phases of their lifecycles. Consequently, the mechanical behavior of steel pipelines is not only influenced by the steel grade but also by the loading history of the pipe segments. Due to the resultant intricacies of the nonlinear load-deformation behavior of pipelines, adequate numerical analysis techniques are usually required for simulation of pipelines under different loading schemes. The validity of such numerical simulations is largely influenced by the accuracy of the true stress-true strain characterization of the pipeline steels. However, existing stress-strain mathematical expressions, developed for the characterization of metallic materials over the full-range of the stress-strain relationship, have been observed to either loose predictive accuracy beyond a limited strain range or, for the more accurate full-range models, are cumbersome due to their requirement of a large number of constituent parameters. This paper presents a relatively accurate and simple true stress-true strain model which is capable of accurately predicting the stress-strain behavior of pipeline steels over the full range of strains. The proposed stress-strain model is characteristically unlike existing stress-strain models as it is essentially defined by a Product-Log function using two proposed parameters, and is capable of capturing a reasonable approximation of the yield plateau in the stress-strain curve. To validate the proposed model, curve-fitting techniques are employed for comparison to experimental data of the stress-strain behavior of different pipeline steel grades (X52 – X100). Excellent agreements are observed between the proposed model and the different pipeline steels over the full-range of the true stress-true strain relationship. Furthermore, the applicability of the proposed model is validated by means of a proposed parametric procedure for predicting the ultimate compressive strength of shell elements.

A Phenomenological Constitutive Model Constructed for PC/ABS Blends

2006 ◽  
Vol 306-308 ◽  
pp. 989-994 ◽  
Author(s):  
M. Nizar Machmud ◽  
Masaki Omiya ◽  
Hirotsugu Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Constitutive Models ◽  
Strain Rates ◽  
Strain Behavior ◽  
Tension Tests ◽  
Proposed Model ◽  
Wide Range ◽  
Different Temperatures ◽  
Prediction Evaluation

Based on previous available constitutive models, a phenomenological constitutive model has been constructed and is proposed to describe the strain, strain rate and temperature dependentdeformation behavior of PC/ABS blends. In this paper, four quasi-static uniaxial tension tests of a specimen tested at different strain rates and temperatures were used to identify the constitutive model constants. By using the proposed constitutive model, predicting the stress-strain behavior of the PC/ABS blend tested at certain strain rate and different temperatures compares well to the behavior exhibited from the tests. From comparison between the DSGZ and the proposed models, proposed model shows a better prediction. Evaluation of the proposed constitutive model was also presented and it has revealed that the proposed model might have a potential to be used for predicting a wide range of temperatures and high strain rates behavior of PC/ABS blends.

Sign in / Sign up

Export Citation Format

Share Document