A new experimental failure model based on triaxiality factor and Lode angle for X-100 pipeline steel

A modified shear-compression specimen (SCS), for large strain testing over a wide range of strain rates is presented. The original SCS design includes two rectangular slots that are machined at 45°with respect to the longitudinal axis. The modification consists of creating two diametrically opposed semi-circular slots. The new "circular" specimen is first thoroughly investigated numerically under quasi-static and dynamic loading using an elastoplastic material model. The results of the comparison between the two-slot designs confirm the feasibility of the new specimen for larger strain testing and indicates its advantages over the rectangular slot design: larger strain range characterization, failure and fracture within the gauge, and constant Lode parameter during plastic deformation. Both types of SCS as well as cylindrical specimens are used to characterize the flow behavior of steel 1020, in the quasi-static and dynamic regimes using a split Hopkinson pressure bar. Dog-bone specimens are also tested quasi-statically in tension. A very good agreement is achieved for the results of all specimens in both the quasi-static and dynamic regimes. The numerical validation procedure shows that the flow stress of 1020 steel obtained with the new SCS is~3 % lower in the quasistatic regime, and 8 % lower in the dynamic regime with respect to the flow stress of the rectangular SCS. This difference is attributed to effect of the third invariant of the stress deviator (i.e., Lode parameter), which is considerably lower in the new SCS design.

show abstract

“…The reason might be the difference in the triaxiality and/or Lode parameter during the plastic deformation, as reported in [23].…”

Section: Numerical Resultsmentioning

confidence: 96%

“…These two parameters are important since they are known to influence the flow behavior and ductility (equivalent plastic strain to failure) of materials [19][20][21][22][23][24]. Fig.…”

Section: Numerical Resultsmentioning

confidence: 99%

Modification of the Shear-Compression Specimen for Large Strain Testing

2015

View full text Add to dashboard Cite

show abstract

“…They conrmed that the use of the Lode angle is a good way to represent the stress state for low or negative stress triaxiality conditions. Other works realized by (Keshavarz et al, 2014), (Xue and Wierzbicki, 2008) and (Mirone and Corallo, 2010) conrmed that the combination of the stress triaxiality ratio T x and Lode angle θ was necessary to dene the stress state accurately.…”

Section: Introductionmentioning

confidence: 95%

Influence of Lode angle on modelling of void closure in hot metal forming processes

Chbihi

Bouchard

Bernacki

et al. 2017

Finite Elements in Analysis and Design

View full text Add to dashboard Cite

show abstract

“…Erice et al [7] took different specimen types of punch, notch, central hole and smiling face type into account, and the results of notched tension confirmed that the ductility increased with the loading velocity increasing. Keshavarz et al [8] extracted the correlation for the failure strain of the pipeline material as a function of triaxiality and Lode angle. Yu et al [9] found that the constitutive equation is insensitive to the change of stress triaxiality for the pressure-insensitive metal under axisymmetric tensile loading.…”

Section: Introductionmentioning

confidence: 99%

Effect of Stress Triaxiality on Plastic Damage Evolution and Failure Mode for 316L Notched Specimen

Peng

Wang

Dai

et al. 2019

Metals

View full text Add to dashboard Cite

To reveal the effect of stress triaxiality on plastic damage evolution and failure mode, 316L notched specimens with different notch sizes are systematically investigated by digital image correlation (DIC) observation, plastic damage analysis by finite element simulation, and void mesoscopic observation. It was found that the plastic damage evolution and failure mode are closely related with notch radius and stress triaxiality. The greater the stress triaxiality at the root is, the greater the damage value at the root is and the earlier the fracture occurs. Moreover, void distribution by mesoscopic observation agrees well with damage distribution observed by finite element simulation with the Gurson-Tvergaard-Needleman (GTN) damage model. It is worth noting that, with the increase in stress triaxiality, the failure mode of notched specimen changes from ductility fracture with void coalescence at the center position to crack initiation at the notch root, from both mesoscopic observation and damage simulation.

show abstract

A new experimental failure model based on triaxiality factor and Lode angle for X-100 pipeline steel

Cited by 19 publications

References 33 publications

Modification of the Shear-Compression Specimen for Large Strain Testing

Modification of the Shear-Compression Specimen for Large Strain Testing

Influence of Lode angle on modelling of void closure in hot metal forming processes

Effect of Stress Triaxiality on Plastic Damage Evolution and Failure Mode for 316L Notched Specimen

Contact Info

Product

Resources

About