Ultimate strength and failure modes for fillet welds in high strength steels

2012 ◽  
Vol 40 ◽  
pp. 36-42 ◽  
Author(s):  
M. Khurshid ◽  
Z. Barsoum ◽  
N.A. Mumtaz
Keyword(s):  
Ultimate Strength ◽  
Failure Modes ◽  
High Strength Steels ◽  
High Strength ◽  
Fillet Welds

scholarly journals Static Strength of Friction-Type High-Strength Bolted T-Stub Connections under Shear and Compression

2020 ◽  
Vol 10 (10) ◽  
pp. 3600 ◽  
Author(s):  
Gangnian Xu ◽  
Youzhi Wang ◽  
Yefeng Du ◽  
Wenshuai Zhao ◽  
Laiyong Wang
Keyword(s):  
Friction Coefficient ◽  
Ultimate Strength ◽  
Compression Ratio ◽  
Failure Modes ◽  
Load Condition ◽  
High Strength ◽  
Shear Capacity ◽  
Displacement Curve ◽  
Clamping Force ◽  
Bolt Diameter

The friction-type high-strength bolted (FHSB) T-stub connection has been widely used in steel structures, due to their good fatigue resistance and ease of installation. While the current studies on FHSB T-stub connections mainly focus on the structural behaviors under both shear and tensile force, no research has been reported on the mechanical responses of the connections under the combined effects of shear and compression. To make up for this gap, this paper presents a novel FHSB T-stub connection, which is simple in structure, definite in load condition, and easy to construct. Static load tests were carried out on 21 specimens under different shear–compression ratios, and the finite-element (FE) models were created for each specimen. The failure modes, initial friction loads and ultimate strengths of the specimens were compared in details. Then, 144 FE models were adopted to analyze the effects of the friction coefficient, shear–compression ratio, bolt diameter and clamping force on the initial friction load and ultimate strength. The results showed that the FHSB T-stub connection under shear and compression mainly suffers from bolt shearing failure. The load–displacement curve generally covers the elastic, yield, hardening and failure stage. If the shear–compression ratio is small and the friction coefficient is large, its curve only contains the elastic and failure stage. The friction coefficient and shear–compression ratio have great impacts on the initial friction load and ultimate strength. For every 1 mm increase in bolt diameter, the initial friction load increased by about 10%, while the ultimate strength increased by about 8.5%. For each 10% increase/decrease of the design clamping force, the initial friction load decreases/increases by 7.8%, while the ultimate load remains basically the same. The proposed formula of shear capacity and self-lock angles of FHSB T-stub connection can be applied to the design of CSS-enhanced prestressed concrete continuous box girder bridges (PSC-CBGBs) and diagonal bracing.

scholarly journals Mechanical properties and corrosion resistance of normal strength and high strength steels in chloride solution

2011 ◽  
Vol 7 (2) ◽  
pp. 94-100 ◽  
Author(s):  
Ahmad Rahbar Ranji ◽  
Amir Hamed Zakeri
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Corrosion Resistance ◽  
Ultimate Strength ◽  
Chloride Solution ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Steels ◽  
Tension Test ◽  
Normal Strength

The corrosion resistance (weight loss) and mechanical properties (i.e. yield strength, ultimate strength and elongation) for three carbon steels, normal strength and high strength steels using tension test are investigated. The specimens are kept in chloride solution (20% NaCl) up to 240 hours. At every 48 hours, thickness and weight loss is measured and tension test is carried out. It was found that the susceptibility of the steels to corrosion based on their weight loss were identical prior to 144 hours, after that is accelerated for high strength steel. In addition, it was found that manganese (Mn) has reduced corrosion rate at early stage of corrosion. The change in mechanical properties by corrosion for all steels are the same, and ultimate strength is reduced, which for limit state design of aged structure should be taken into account.DOI: 10.3329/jname.v7i2.5309

Dissimilar Material Joint Strength and Structure for Friction Stir Forming Process

2014 ◽  
Author(s):  
Kenneth A. Ogata ◽  
Sladjan Lazarevic ◽  
Scott F. Miller
Keyword(s):  
Failure Modes ◽  
Dissimilar Materials ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Process ◽  
Experimental Conditions ◽  
Friction Stir ◽  
Automotive Body ◽  
Neck Fracture ◽  
Ultra High Strength Steels

Mass reduction of automotive body structures is a critical part of achieving reduced CO2 emissions in the automotive industry. There has been significant work on the application of ultra high strength steels and aluminum alloys. However, the next paradigm is the integrated use of both materials, which creates the need to join them together. Friction stir forming is a new environmentally benign manufacturing process for joining dissimilar materials. The concept of this process is stir heating one material and forming it into a mechanical interlocking joint with the second material. In this research the process was experimentally analyzed in a computer numerical controlled machining center between aluminum and steel work pieces. The significant process parameters were identified and their optimized settings for the current experimental conditions defined using a design of experiments methodology. Three failure modes were identified (neck fracture, aluminum sheet peeling, and bonding delamination i.e. braze fracture). The overall joint structure and grain microstructure were mapped along different stages of the friction stir forming process. Two layers were formed within the aluminum, the thermo-mechanical affected zone that had been deformed due to the contact pressure and angular momentum of the tool, and the heat affected deformation zone that deformed into the cavity.

scholarly journals Experimental investigation of two-bolt connections for high strength steel members

2018 ◽  
Author(s):  
Yan-Bo Wang ◽  
Yi-Fan Lyu ◽  
Guo-Qiang Li
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
High Strength Steels ◽  
High Strength ◽  
Double Shear ◽  
Loading Direction ◽  
Steel Members ◽  
Edge Distance ◽  
End Distance ◽  
Bolt Spacing

This paper presents an experimental research on bearing-type bolted connections consisting of two bolts positioned perpendicular to the loading direction. A total of 24 connections in double shear fabricated from high strength steels with yield stresses of 677MPa and 825MPa are tested. Two failure modes as tearout failure and splitting failure are observed in experiments. The effect of end distance, edge distance, bolt spacing and steel grade on the failure mode and bearing behavior are discussed. For connection design with bolts positioned perpendicular to loading direction, it is further found that combination of edge distance and bolt spacing effectively determines the failure mode and ultimate load. The test results are compared with Eurocode3. An optimal combination of edge distance and bolt spacing as well as related design suggestion is thus recommended. 

Behaviour of concrete-filled steel tubular members under pure bending and acid rain attack: Test simulation

2018 ◽  
Vol 22 (1) ◽  
pp. 240-253 ◽  
Author(s):  
Li Xie ◽  
Mengcheng Chen ◽  
Wei Sun ◽  
Fang Yuan ◽  
Hong Huang
Keyword(s):  
Acid Rain ◽  
Ultimate Strength ◽  
Failure Modes ◽  
High Strength ◽  
Recycled Concrete ◽  
Steel Plates ◽  
Concrete Aggregate ◽  
Deformation Curves ◽  
Section Modulus ◽  
Four Point Bending

As infrastructure in China continues to develop rapidly, concrete-filled steel tubular structures are increasingly attracting interest for use in construction engineering owing to their high section modulus, high strength and good seismic performance characteristics. However, acid rain occurs throughout much of China, and the mechanical behaviour of concrete-filled steel tubular members may be affected by the corrosive environment created by acid rain. In this study, a total of 14 circular and square-shaped concrete-filled steel tubular members made of different types of concrete (general and recycled) and with varying corrosion rates (0%, 10%, 20% and 30%) were tested under four-point bending. After testing, the flexural behaviour of the corroded and uncorroded concrete-filled steel tubular beams were analysed in detail in terms of their failure modes, moment versus deformation curves and ultimate strength. The results indicate that the corrosion leads to an evident decrease in yield strength, elastic modulus and tensile strain capacity of steel plates and also to a noticeable deterioration in the ultimate strength of the concrete-filled steel tubular members. The replacement of general concrete aggregate with recycled concrete aggregate has little impact on the flexural performance of corroded and uncorroded concrete-filled steel tubular beams. Finally, comparisons were made between the experimental results and predicted ultimate strengths from four existing codes (GB 50936-2014, DB36/J001-2007, AIJ and EN 1994-1-1:2004).

Influence of Microstructure on Damage in Advanced High Strength Steels

2012 ◽  
Vol 706-709 ◽  
pp. 925-930 ◽  
Author(s):  
Frank Hisker ◽  
Richard Thiessen ◽  
Thomas Heller
Keyword(s):  
Work Hardening ◽  
Tensile Testing ◽  
Failure Modes ◽  
Tensile Elongation ◽  
High Strength Steels ◽  
High Strength ◽  
Body Parts ◽  
Hole Expansion ◽  
Advanced High Strength Steels ◽  
Dp Steels

AHSS (Advanced High Strength Steels) combine high strength and good ductility. Their outstanding forming and work-hardening behavior predestines these steels for fabrication of strength relevant structural elements and automobile body parts. To characterize a material, not only tensile, but also hole-expansion and bending behavior are important and help predict the stretch-flange-formability. In this study, detailed analyses of the correlation between these three tests and the damage mechanisms during forming have been performed for selected steels. The results show that for AHSS one should differentiate between “local” and “global” failure. Furthermore, not only are certain materials more sensitive to local or global damage, but also various testing methods tend to provoke either local or global damage. Tensile testing provokes global failure whereas hole-expansion tends to induce local failure. A specimen fails during bending with a mixture of local and global modes. These failure modes are strongly attributed to the microstructure. DP-steels yield high elongation during tensile testing and poorer hole-expansion values. High-resolution EBSD has revealed that the microstructure of DP-steels is sensitive to localized damage, which is compensated by work-hardening around damaged regions and thus shifts the loading to un-hardened regions. This makes DP-microstructures well-suited to tensile loading but sensitive to hole-expansion. CP-steels of comparable strength show poorer tensile elongation and higher hole-expansion ratios due to a microstructure which is not sensitive to localized failure (but has limited capacity for work-hardening). The failure mode in TRIP-steels exhibits a similar character as in DP-steels, but only after the martensitic transformation of retained austenite.

scholarly journals Bonded CFRP to high strength steels

2019 ◽  
Vol 52 (4) ◽  
pp. 222-235
Author(s):  
Mohsen Amraei ◽  
Lingjia Zong ◽  
Antti Ahola ◽  
Timo Björk
Keyword(s):  
Ultimate Strength ◽  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
High Modulus ◽  
Cfrp Laminates ◽  
Bond Performance ◽  
The Past ◽  
Ultra High Strength Steel ◽  
Series Of Experiments

Research on the bond performance of CFRP-strengthened steel have been done for the past years, but it has mainly focused on lower grades of steel. The performance of the bond between ultra-high modulus (UHM) CFRP and high/ultra-high strength steel (HSS/UHSS) is investigated in this paper. A series of experiments have been conducted, with single/double side-strengthened (SSS/DSS) HSS/UHSS with CFRP laminates using Araldite adhesive. It was found that strengthening up to the ultimate strength of the DSS specimens is feasible. However, debonding happens at the ultimate strength of SSS specimens.

scholarly journals Experimental study of the mechanical strength and the failure of multi-sheet, multi-material spot-welded assemblies under pure and combined loading conditions

2018 ◽  
Vol 183 ◽  
pp. 02009 ◽  
Author(s):  
Rim Chtourou ◽  
Fahmi Chaari ◽  
Gregory Haugou ◽  
Nicolas Leconte ◽  
Eric Markiewicz ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Failure Modes ◽  
High Strength Steels ◽  
High Strength ◽  
The Body ◽  
Combined Loading ◽  
Strength Failure ◽  
Shear Modes ◽  
Multiple Materials ◽  
Spot Welded

Resistance Spot Welding (RSW) is widely used in the automotive industry thanks to its production convenience and cost effectiveness. Around four thousands spot welds are indeed employed to assemble the body-in-white. RSW of multiple sheets and combining multiple materials are increasingly realized. The Ultra-High-Strength Steels (UHSS) are particularly well suited for the entire range of structural parts requiring good crash resistance. However, the mechanical strength and the rupture of such new generation of RSW under multi-axial loadings is not yet well studied. The present work investigates the mechanical strength and the failure of a three-sheet spot welded assembly composed of two sheets of UHSS 22MnB5 and a third sheet of mild steel DX54D. An advanced experimental procedure is proposed for testing this assembly in pure and combined (tensile shear modes) modes I/II. Two types of specimen with different sheet thicknesses have been studied. The obtained results are analyzed to investigate the loading angle effect and the assembly configuration effect on the mechanical strength. Failure modes are also studied in relation with the increasing of the loading angle. Finally, the parameters of a macroscopic force-based failure criterion dedicated for FE crash modeling are identified.

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