scholarly journals Material Behavior Description for a Large Range of Strain Rates from Low to High Temperatures: Application to High Strength Steel

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 795 ◽  
Author(s):  
Pierre Simon ◽  
Yaël Demarty ◽  
Alexis Rusinek ◽  
George Voyiadjis
Keyword(s):  
High Strength Steel ◽  
Constitutive Relations ◽  
High Strength ◽  
Numerical Approach ◽  
Complex Stress ◽  
Material Behavior ◽  
Experimental Results ◽  
Large Field ◽  
Strain Rates ◽  
Behavior Description

Current needs in the design and optimization of complex protective structures lead to the development of more accurate numerical modelling of impact loadings. The aim of developing such a tool is to be able to predict the protection performance of structures using fewer experiments. Considering only the numerical approach, the most important issue to have a reliable simulation is to focus on the material behavior description in terms of constitutive relations and failure model for high strain rates, large field of temperatures and complex stress states. In this context, the present study deals with the dynamic thermo-mechanical behavior of a high strength steel (HSS) close to the Mars® 190 (Industeel France, Le Creusot, France). For the considered application, the material can undergo both quasi-static and dynamic loadings. Thus, the studied strain rate range is varying from 10−3–104 s−1. Due to the fast loading time, the local temperature increase during dynamic loading induces a thermal softening. The temperature sensitivity has been studied up to 473 K under quasi-static and dynamic conditions. Low temperature measurements (lower than the room temperature) are also reported in term of σ − ε | ε ˙ , T curves. Experimental results are then used to identify the parameters of several constitutive relations, such as the model developed initially by Johnson and Cook; Voyiadjis and Abed; and Rusinek and Klepaczko respectively termed Johnson–Cook (JC), Voyiadjis–Abed (VA), and Rusinek–Klepaczko (RK). Finally, comparisons between experimental results and model predictions are reported and compared.

scholarly journals Mechanical behaviour modelling under dynamic conditions: Application to structural and high strength steels

2018 ◽  
Vol 183 ◽  
pp. 01056
Author(s):  
Pierre Simon ◽  
Yaël Demarty ◽  
Alexis Rusinek
Keyword(s):  
Strain Rate ◽  
Dynamic Loading ◽  
High Strain ◽  
Constitutive Relations ◽  
High Strength Steels ◽  
Rate Sensitivity ◽  
High Strength ◽  
Numerical Approach ◽  
Large Field ◽  
Dynamic Conditions

Current needs in the design and optimization of complex ballistic protection structures lead to the development of more and more accurate numerical modelling for high impact velocity. The aim of developing such a tool is to be able to predict the protection performance of structures using few experiments. Considering only numerical approach, most important issue to have a reliable simulation is to focus on material behaviour description in term of constitutive relation and failure model for high strain rates, large field of temperatures and complex stress states. In this context, the study deals with the behaviour of two steels including a high strength steel and a structural steel. For this application, the materials can undergo both quasi-static and dynamic loading. Thus the strain rate range studied is varying from 10−3 to more than 103 s−1. Although the high strength steels do not exhibit high strain rate sensitivity, the temperature increases during dynamic loading is inducing thermal softening. Thus, temperature sensitivity is defined up to 500 K under quasi-static and dynamic conditions. Then, experiments are used to define the parameters of several constitutive relations like the Johnson-Cook model or the Rusinek Klepaczko model.

scholarly journals FEM Study of a Steel Corrugated Web Plate Girder Subjected to Fire

2021 ◽  
Vol 26 (2) ◽  
pp. 201-218
Author(s):  
D. Sokołowski ◽  
M. Kamiński
Keyword(s):  
High Strength Steel ◽  
Constitutive Relations ◽  
High Strength ◽  
Experimental Tests ◽  
Physical Parameters ◽  
Bottom Flange ◽  
Gas Temperature ◽  
Temperature Dependent ◽  
Corrugated Web ◽  
Plate Girder

Abstract The main aim of this work is a computational nonlinear analysis of a high strength steel corrugated-web plate girder with a very detailed and realistic mesh including vertical ribs, all the fillet welds and supporting areas. The analysis is carried out to verify mechanical structural response under transient fire temperature conditions accounting for an efficiency and accuracy of three various transient coupled thermo-elastic models. All the resulting stress distributions, deformation modes and their time variations, critical loads and eigenfrequencies as well as failure times are compared in all these models. Nonlinearities include material, geometrical and contact phenomena up to the temperature fluctuations together with temperature-dependent constitutive relations for high strength steel. They result partially from steady state and transient experimental tests or from the additional designing rules included in Eurocodes. A fire scenario includes an application of the normative fire gas temperature curve on the bottom flange of the entire girder for a period of 180 minutes. It is computed using sequentially coupled thermo-elastic Finite Element Method analyses. These account for heat conductivity, radiation and convection. The FEM model consists of a combination of 3D hexahedral and tetrahedral solid finite elements and uses temperature-dependent material and physical parameters, whose values are taken after the experiments presented in Eurocodes. Numerical results presented here demonstrate a fundamental role of the lower flange in carrying fire loads according to this scenario and show a contribution of the ribs and of the welds to the strength of the entire structure.

scholarly journals The effect of mean axial and torsional stresses on the fatigue strength of 34CrNiMo6 high strength steel

2019 ◽  
Vol 300 ◽  
pp. 16004
Author(s):  
Luis Pallarés-Santasmartas ◽  
Joseba Albizuri ◽  
Nelson Leguinagoicoa ◽  
Nicolas Saintier ◽  
Jonathan Merzeau
Keyword(s):  
High Strength Steel ◽  
Fatigue Behavior ◽  
High Strength ◽  
Fatigue Loading ◽  
Experimental Results ◽  
Shear Stresses ◽  
Mean Stress ◽  
Theoretical Predictions ◽  
Loading Case ◽  
Fracture Appearance

The present study consists of a theoretical, experimental and fractographic investigation of the effect of superimposed static axial and shear stresses on the high cycle fatigue behavior of a 34CrNiMo6 high strength steel in quenched and tempered condition (UTS = 1210 MPa), commonly employed in highly stressed mechanical components. The Haigh diagrams for the axial and torsional cases under different values of mean stress were obtained. In both cases, experimental results showed that increasing the mean stress gradually reduces the stress amplitude that the material can withstand without failure. The results of the present tests are compared with the theoretical predictions from Findley, based on the maximum damage critical plane; and the methods of Marin and Froustey, which are energetic based criterions. Froustey’s method shows the best agreement with experimental results for torsional fatigue with mean shear stresses, showing a non-conservative behaviour for the axial fatigue loading case. Macro-analyses and micro-analyses of specimen fracture appearance were conducted in order to obtain the fracture characteristics for different mean shear stress values under torsion fatigue loading.

Compressive Properties of High Strength Steel Fiber Reinforced Concrete with Different Fiber Volume Fractions

2013 ◽  
Vol 372 ◽  
pp. 215-218 ◽  
Author(s):  
Hye Ran Kim ◽  
Seung Ju Han ◽  
Hyun Do Yun
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Strength Steel ◽  
Steel Fiber ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Experimental Results ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Volume Fractions

This paper describes the experimental results of 70 MPa high strength steel fiber reinforced concrete (SFRC) with different steel fiber volume fractions in compression. The effect of steel fiber on fresh properties, compressive strength, toughness index, cracking procedure of high strength steel fiber concrete is also investigated. The steel fibers were added as the volume fractions of 0%, 0.5%, 1.0%, 1.5% and 2.0%. The cylindrical specimens with Φ100 x 200 for compressive tests were manufactured in accordance with ASTM C 39[. The experimental results showed that the slump of fresh SFRC was inversely proportional to the fiber volume fraction added to high strength concrete. As the addition of steel fiber increased, compressive strength of SFRC decreased. Inclusion of steel fiber improves compressive toughness of high strength SFRC.

Forming Limits of Several High-Strength Steel Sheets under Proportional/Non-Proportional Deformation Paths

2014 ◽  
Vol 939 ◽  
pp. 260-265 ◽  
Author(s):  
Ryutaro Hino ◽  
Satoki Yasuhara ◽  
Yutaka Fujii ◽  
Atsushi Hirahara ◽  
Fusahito Yoshida
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Experimental Results ◽  
Forming Limit ◽  
Type Analysis ◽  
Forming Limits ◽  
Steel Sheets ◽  
Path Dependent ◽  
Forming Limit Curves ◽  
Good Agreement

Forming limits of several high-strength steel (HSS) sheets under non-proportional deformation paths were examined experimentally and predicted analytically. Forming limit curves (FLCs) for 590MPa, 780MPa and 980MPa grade HSS sheets were obtained by performing stretch forming tests under proportional deformation and two types of non-proportional deformation. The experimental results showed strong path-dependent characteristics of FLCs of HSS sheets. Forming limits of equi-biaxially prestrained HSS sheets became markedly lower compared to the original FLCs under proportional deformation, while forming limits of uniaxially prestrained HSS sheets became partially higher than the original FLCs. It was confirmed that Marciniak-Kuczyński type analysis gave reasonably good predictions of forming limits under non-proportional deformation paths. Especially forming limit predictions of equi-biaxially-prestrained sheets showed good agreement with the corresponding experimental results.

Application of 3D digital image correlation for the measurement of the tensile mechanical properties of high-strength steel

2021 ◽  
Vol 63 (4) ◽  
pp. 303-310
Author(s):  
Feipeng Zhu ◽  
Xiaoxia Gu ◽  
Pengxiang Bai ◽  
Dong Lei
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Digital Image Correlation ◽  
Yield Strength ◽  
Digital Image ◽  
High Strength Steel ◽  
High Strength ◽  
Experimental Results ◽  
Image Correlation ◽  
3D Digital Image Correlation

Abstract High-strength steel plays an important role in engineering fields such as infrastructure. For this reason, an accurate determination of its mechanical properties is of critical importance. Considering the inconvenience of conventional mechanical extensometers for the deformation measurement of small-scale specimens, 3D digital image correlation (3D-DIC) was used to measure the deformation of Grade 8.8 bolts and Q690 high-strength steel specimens by means of a uniaxial tensile test, and in this way, stress–strain curves, elastic modulus, yield strength, tensile strength, percentage elongation after fracture, and percentage reduction of area were obtained. Experimental results show that Grade 8.8 bolts and Q690 steel result in higher yield strength and tensile strength than common steel. Moreover, owing to the phenomenon that stress remains constant with strain increase in the yielding stage, the evolution process from elastic deformation to plastic deformation of the specimens during the yielding stage could be studied. Experimental results show that the axial strain of Grade 8.8 bolts increases from 0.3 to 1 % during the yielding stage and for Q690 specimens the corresponding strain increases from 0.4 to 1.8 %.

Sign in / Sign up

Export Citation Format

Share Document