On Utilization of Material Failure Criterion in Modeling Pull-Out Failure of Spot-Welded Joints

2013 ◽  
Author(s):  
Long Zeng ◽  
Yong Xia ◽  
He Zhao ◽  
Qing Zhou
Keyword(s):  
Test Data ◽  
Failure Criterion ◽  
Welded Joints ◽  
Failure Modes ◽  
Failure Criteria ◽  
Spot Weld ◽  
Test Results ◽  
Pull Out ◽  
Metal Sheets ◽  
Spot Welded

Two distinct failure modes of spot welds, interfacial and pull-out failure, are observed in impact of spot-welded structures. Automotive industries prefer pull-out as the predominant failure mode since it makes more use of load-bearing capacity of a joint. For the time being, finite element models for predicting pull-out failure of spot weld have not been well developed. The dependence of failure on the stress state, i.e., a locus in the space of failure strain and stress triaxiality, needs to be known for base metal sheets when modeling spot weld pull-out. Existing failure criteria, with or without physical base, were formulated to provide an effective way to utilize a limited number of tests to reconstruct the failure locus. This paper is aimed to evaluate influence of failure criterion form for identifying failure parameters on modeling spot weld pull-out. As for material tests, various specimen configurations of metal sheets were designed to obtain stress states around a number of typical stress triaxialities. These test results constructed a set of test data for calibrating failure criterion. The spot-welded joints were also tested two different coupon configurations. The force-displacement curves were obtained, and the deformation fields around the spot weld nugget were achieved with DIC. These test results of joints were utilized to validate the model of spot weld pull-out. Two prevailing failure criteria, shear-modified Gurson model and Modified Mohr-Coulomb model, were selected to predict the complicated spot weld pull-out failure. Parameters in each of the two failure criteria were identified with material test data. Various simulation results were thereafter obtained based on different failure criteria. The two criteria were evaluated in terms of their predictive capabilities for spot weld pull-out failure.

scholarly journals Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1021
Author(s):  
Yunzhao Li ◽  
Huaping Tang ◽  
Ruilin Lai
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Strong Dependence ◽  
High Strength ◽  
Weld Nugget ◽  
Resistance Spot ◽  
Pull Out ◽  
Cross Tension ◽  
Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

PULL OUT STRENGTH FOR DIFFERENT SIZE OF DOWEL AND GRAIN DIRECTION OF GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Mohamad Iswandi Jinne ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Experimental Program ◽  
Drilling Process ◽  
Test Results ◽  
Bond Behaviour ◽  
Pull Out ◽  
Timber Joints ◽  
Different Thickness ◽  
Pull Out Strength

This paper presents an experimental program for testing glued-in dowel glulam timber joints. Hundred thirty glulam specimens, each with a single glued-in rebar parallel to the grain and perpendicular to grain with different size of dowels 12mm, 16mm and 20mm were tested to evaluate the effects of anchorage length and different dowel diameter for parallel and perpendicular to the grain on pull-out strength and bond behaviour of glued-in rebar timber joints. The test results showed that the maximum load for specimen with dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction. Failure modes were characterized by pull out failure in the mode of adhesive-dowel, yet one sample failed in timber-adhesive mode. This might happened because the surface of the timber was burned by drilling machine during the drilling process. The pull-out was tested with different thickness grain direction with different dowel size with a rate of 2mm/min and the failure modes were observed after the testing of pull-out test. PRF is the adhesive used for the strengthening purposes. Resistance to the withdrawal of dowels glued-in perpendicularly was 44.2% to 53.5 % lower than that obtained for dowels glued-in parallel to the grain direction. The result shows that the dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction.

A strain energy criterion for failure of floating ice sheets

1978 ◽  
Vol 5 (3) ◽  
pp. 352-361 ◽  
Author(s):  
S. Beltaos
Keyword(s):  
Failure Criterion ◽  
Strain Energy ◽  
Unit Volume ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Energy Criterion ◽  
Failure Criteria ◽  
Test Results ◽  
Practical Limit ◽  
Loading Tests

A failure criterion for floating ice sheets under stationary loads is presented, based on the concept of strain energy per unit volume and the results of some 40 prototype loading tests. The practical requirement for a time-independent failure criterion for ice, which is a viscoelastic material and thus subject to creep, is noted. Existing failure criteria are reviewed and shown to be unable to handle many practical situations. Subsequently, the concept of strain energy per unit volume is formulated and shown to provide a satisfactory failure criterion under varied loading histories. Analysis of the test results indicated the existence of a distinct instant marking the onset of failure of a loaded ice sheet. Because the behaviour of a loaded ice sheet between this instant and the final breakthrough of the load is partially random, it is suggested that the former be used as the practical limit of safety.

Studies on Soil Resistance to Pipelines Buried in Sand

2011 ◽  
Vol 243-249 ◽  
pp. 3151-3156 ◽  
Author(s):  
Run Liu ◽  
Lin Ping Guo ◽  
Shu Wang Yan ◽  
Yu Xu
Keyword(s):  
Failure Modes ◽  
Model Tests ◽  
Soil Resistance ◽  
Test Results ◽  
Buried Pipe ◽  
Pull Out ◽  
Soil Failure ◽  
Pipe Segment ◽  
Force Displacement ◽  
Peak Value

A series of model tests were carried out to investigate the soil resistance when the buried pipe segment moved in the sand. In the tests, the pipe segments were pulled out in vertical, lateral and axial directions and the pipe segments movement and soil resistance were recorded. Observed data show that the soil resistance depends on the pipe diameters and the depth of cover. According to the uplift test results, the force-displacement relationships with smaller depth of cover are greatly different from those with larger depth of cover. The results of the lateral sliding and axial pull out tests show that the soil resistance initially increases before a peak value is reached and then keeps the same level. For the same covered depth, the lateral soil resistance is more than twice that for uplift. According to the uplift test results, the soil failure modes with smaller depth of cover are greatly different from those with larger covered depth.

Properties and characteristics of cold spot welded joints of metal sheets

1997 ◽  
Vol 33 (4) ◽  
pp. 456-459
Author(s):  
É. É. Kol'man-Ivanov ◽  
I. V. Bel'tyukova
Keyword(s):  
Welded Joints ◽  
Cold Spot ◽  
Metal Sheets ◽  
Spot Welded

scholarly journals Experimental Analysis and Failure Criterion of Plain Concrete Subjected to Biaxial Loading under Fixed Lateral Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Zhenpeng Yu ◽  
Xue Sun ◽  
Furong Li
Keyword(s):  
Principal Stress ◽  
Failure Criterion ◽  
Failure Modes ◽  
Biaxial Loading ◽  
Plain Concrete ◽  
Failure Criteria ◽  
Lateral Loading ◽  
Biaxial Compression ◽  
Proportional Loading ◽  
Stress Ratios

By using a rock true triaxial apparatus hydraulic servo machine, biaxial loading experiments including biaxial compression-compression and biaxial compression-tension with fixed lateral loading on plain concretes were conducted and the stress-strain curves of plain concrete under various stress ratios were obtained. After determining the peak principal stress, the damage modes of plain concrete under various stress ratios were analyzed and the law of strength in the principal stress direction was studied as well. The experimental findings show that, under the fixed lateral loading, the failure modes of plain concrete under biaxial compression-compression and biaxial compression-tension are very similar to those under the equal proportional loading, but with higher amplitude of variation. In this paper, Kupfer’s classical failure criterion was applied to verify the experimental data and the predicted biaxial loading on plain concrete under fixed lateral loading and was regarded as relatively conservative. Meantime, based on Kupfer’s failure criterion and octahedral stress space, two different failure criteria had been proposed and verified. The results show that the proposed failure criteria have good applicability. The failure mechanism under fixed lateral loading was discussed and compared with that under the equal proportional loading method. This research is meaningful to plain concrete engineering application and calculation.

scholarly journals Experimental and Parametric Study on the Pull-Out Resistance of a Notched Perfobond Shear Connector

2019 ◽  
Vol 9 (4) ◽  
pp. 764 ◽  
Author(s):  
Shuangjie Zheng ◽  
Yuqing Liu ◽  
Yangqing Liu ◽  
Chen Zhao
Keyword(s):  
Failure Modes ◽  
Concrete Strength ◽  
Shear Connector ◽  
Test Results ◽  
Explicit Finite Element ◽  
Shear Connectors ◽  
Pull Out ◽  
Cutting Out ◽  
Circular Holes ◽  
Alternative Equation

To ease the installation of perforating rebars through multi-holes, an alternative notched perfobond shear connector was proposed by cutting out the hole edge. This paper presents the test results of six pull-out specimens with conventional and notched perfobond shear connectors. The objective was to compare the failure modes and pull-out behaviors of perfobond shear connectors using circular holes and notched holes. Furthermore, the explicit finite element method was introduced and validated to generate parametric results for pull-out tests of notched perfobond shear connectors. A total of 33 parametric simulations were performed to further study the influences of several variables, including the hole diameter, the cut width, the perfobond thickness, the concrete strength, the diameter and strength of the rebar, and the strength of the structural steel. The experimental and numerical results were used to evaluate the previous equations for perfobond shear connectors. Finally, an alternative equation was proposed to estimate the pull-out resistance of notched perfobond shear connectors.

Dynamic bearing capacity of point fixed corrugated metal profile sheets subjected to blast loading

2021 ◽  
pp. 204141962110592
Author(s):  
Kai Fischer ◽  
Jan Dirk van der Woerd ◽  
Wilfried Harwick ◽  
Alexander Stolz
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Load Transfer ◽  
Structural Response ◽  
Blast Loading ◽  
Risk And Resilience ◽  
Structural Members ◽  
Pull Out ◽  
Metal Sheets ◽  
Corrugated Metal

Blast loading scenarios and the corresponding hazards have to be evaluated for infrastructure elements and buildings especially at industrial sites for safety and security issues. Point fixed corrugated metal sheets are often applied as façade elements and can become a hazard for humans if they are pulled off. This paper investigates the dynamic bearing capacity of such structural members in terms of their general bending behavior in the middle of the span and pull-out behaviors at the fixing points. The elements are fixed at two sides and the load transfer is uniaxial. An experimental series with static and dynamic tests forms the basis to identify the predominant failure modes and to quantify the maximum stress values that can be absorbed until the investigated structural members fail. The experimental findings are applied to create and to optimize an engineering model for the fast and effective assessment of the structural response. The aim is the derivation of a validated model which is capable to predict the blast loading behavior of metal sheets including arbitrary dimensions, material properties, and screw connections. Results of this study can be integrated into a systematic risk and resilience management process to assess expected damage effects and the evaluation of robustness.

Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

2011 ◽  
Vol 25 (3) ◽  
pp. 647-653 ◽  
Author(s):  
Soran Hassanifard ◽  
Mohammad Zehsaz ◽  
Firooz Esmaeili
Keyword(s):  
Welded Joints ◽  
Fatigue Behavior ◽  
Spot Weld ◽  
Spot Welded

scholarly journals Effects of Al-Si Coating on Static and Dynamic Strength of Spot-Welded Hot-Stamping Steel Joints

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 976
Author(s):  
Ali Afzal ◽  
Mohsen Hamedi ◽  
Chris Valentin Nielsen
Keyword(s):  
Tensile Strength ◽  
Welded Joints ◽  
Dynamic Force ◽  
Dynamic Tests ◽  
Tensile Shear ◽  
Resistance Spot ◽  
Pull Out ◽  
Static And Dynamic Tests ◽  
Hot Stamped Steel ◽  
Spot Welded

Al-Si is the most popular coating used to prevent oxidation on the surfaces of hot-stamped steel sheets during the heating process. However, like other coatings, it affects the strength of the spot welds in joining the hot-stamped steel parts. In this study, the effects of Al-Si coating on the tensile strength of the resistance spot-welded joints in hot-stamped steel are discussed. Two types of 1.8 mm hot-stamped steel, in uncoated and Al-Si coated forms, were resistance spot-welded, and the tensile shear behavior of the welded joints was studied in both static and dynamic tests. To do this, a special fixture for impact tensile shear tests was designed and fabricated. In the case of the Al-Si coated steel, the presence of the molten Al-Si over the fusion zone, especially its aggregation in the edge of the weld nugget, caused a decrease in the maximum tensile load capacity and a failure of energy absorption in static and dynamic tests, respectively. Additionally, it increased the probability of changing its failure mode from pull out to interfacial fracture in the dynamic test. This study shows that the tensile strength behavior of the welded joints for the Al-Si coated hot-stamped steel is lower than the uncoated steel during static, and especially dynamic, force.

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