Experimental Investigations of the Effects of Multiple Heat Straightening Repair on the Structural Properties of Bridge Steels

The effects of multiple damage-heat straightening repair cycles (i.e., multiple cycles of damage followed by heat straightening repair) on the fundamental structural properties of typical bridge steels ASTM A36, A588, and A7 were evaluated. The damage and repair parameters considered in the study are the damage strain (ed), the restraining stress (sr), and the number of multiple damage-repair cycles (Nr). The effects of these parameters on the following structural properties were evaluated: elastic modulus, yield stress, ultimate stress, percent elongation, surface hardness, and fracture toughness. Seventy-five laboratory-scale specimens made from A36, A588, or A7 steel were subjected to multiple damage-repair cycles, and their effects on the structural properties were evaluated. The results indicate that multiple damage-repair cycles have a small influence (±15%) on the elastic modulus, yield stress, and ultimate stress. However, the percent elongation and fracture toughness of the damaged-repaired steel are influenced significantly. On the basis of reductions in the percent elongation and fracture toughness, it is recommended that A7 and A36 steel be limited to three damage-heat straightening repair cycles. A588 steel can be subjected to five damage-heat straightening repair cycles.

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Assessment of Mechanical Properties of Cold Formed Steel Material at Elevated Temperature

Materials Science Forum ◽

10.4028/www.scientific.net/msf.846.27 ◽

2016 ◽

Vol 846 ◽

pp. 27-36

Author(s):

Fadhluhartini Muftah ◽

Mohd Syahrul Hisyam Mohd Sani ◽

Ahmad Rasidi Osman ◽

Mohd Azran Razlan ◽

Shahrin Mohammad

Keyword(s):

Elastic Modulus ◽

Elevated Temperature ◽

Ambient Temperature ◽

Yield Stress ◽

Material Properties ◽

High Efficiency ◽

Strain Curve ◽

Ultimate Stress ◽

Fire Incident ◽

Cold Formed Steel

Fire accident is considered as the one of most severe environmental hazards to building and infrastructure. Cold formed steel (CFS) beam has been used extensively as primary load bearing structural member in many applications in the building construction due to high efficiency in term of production, fabrication, and assembling in construction. This material must be well perform in fire incident in term of its integrity and stability of structural for a period of time. Hence, the assessment of the material properties of this material is greatly important in order to predict the performance of this structure under fire incident. The tensile coupon tests of CFS are according to BS EN 10002-1:2001. The CFS material G450 with 1.9 mm thickness is used in this study. The elastic modulus, yield stress, correspondent percentage strain at yield stress, ultimate stress, and correspondent percentage strain of ultimate stress was 200.3 GPa, 540.5 MPa, 0.478 %, 618.8 MPa, and 8.701 % respectively. The results of the ambient temperature test have been used to assess the mechanical strength of CFS at elevated temperature. The discussion of material properties is based on EC3-1-2 and proposed model from other researchers. The main material properties discussed is the stress-strain curve, elastic modulus, yield strength at elevated temperature was determined. The actual elastic region is slightly lower than the prediction of EC3-1.2 at ambient temperature, but well fit with two other studies. Besides that, the actual material properties experience strain hardening after yielding and reach a maximum stress up to 618 MPa while EC3-1.2 predict the constant value of the yield stress after yield until 15 % strain,other two study was fit the ambient tensile test up to ultimate stress, and fit until 2 % strain level.

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Mechanical characterization of polylactic acid, polycaprolactone and Lay-Fomm 40 parts manufactured by fused deposition modeling, as a function of the printing parameters

ITECKNE Innovación e Investigación en Ingeniería ◽

10.15332/iteckne.v16i2.2354 ◽

2019 ◽

Vol 16 (2) ◽

pp. 25-31 ◽

Cited By ~ 1

Author(s):

Jessica Zuleima Parrado-Agudelo ◽

Carlos Narváez-Tovar

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Yield Stress ◽

Fused Deposition Modeling ◽

Material Selection ◽

Ultimate Tensile Stress ◽

Ultimate Stress ◽

Fused Deposition ◽

Raster Angle ◽

Printing Parameters

This study aims to determine the mechanical properties of parts manufactured by Fused Deposition Modeling (FDM) using three biocompatible polymer materials: Polylactic Acid (PLA), Polycaprolactone (PCL) and Lay-Fomm 40. Also, it was analyzed the influence of different printing parameters, material selection, infill percentage, and raster angle, over the mechanical properties. The samples were subjected to tension and compression tests using a universal testing machine, and elastic modulus, yield stress, and ultimate stress were obtained from the stress-strain curves. PLA samples have the highest elastic modulus, yield stress and ultimate stress for both compression and tension tests, for example, the ultimate tensile stress with infill percentage of 30 % and raster angle of 0-90° has an average value of 41.20 MPa, while PCL samples had an ultimate tensile stress average value of 9.68 MPa. On the other hand, Lay-Fomm40 samples had the highest elongations, with percentage values between 300 and 600 %. Finally, ANOVA analysis showed that the choice of the material is the leading printing parameter that contributes to the mechanical properties, with percentages of 84.20% to elastic modulus, 93.30% to yield stress, and 82.44% to ultimate stress. The second important factor is the raster angle, with higher strengths for the 0-90° when compared to 45-135°. On the other hand, the contribution of the infill percentage to the mechanical properties was no statistically significant. The obtained results could be useful for material selection and 3D printing parameters definition for additive manufacturing of scaffolds, implants, and other structures for biomedical and tissue engineering applications.

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Fundamentals of cutting

Interface Focus ◽

10.1098/rsfs.2015.0108 ◽

2016 ◽

Vol 6 (3) ◽

pp. 20150108 ◽

Cited By ~ 15

Author(s):

J. G. Williams ◽

Y. Patel

Keyword(s):

Fracture Toughness ◽

Elastic Modulus ◽

Fracture Mechanics ◽

Yield Stress ◽

Material Properties ◽

Orthogonal Cutting ◽

Wedge Angle ◽

Tool Geometry ◽

Plastic Shear ◽

Plastic Bending

The process of cutting is analysed in fracture mechanics terms with a view to quantifying the various parameters involved. The model used is that of orthogonal cutting with a wedge removing a layer of material or chip. The behaviour of the chip is governed by its thickness and for large radii of curvature the chip is elastic and smooth cutting occurs. For smaller thicknesses, there is a transition, first to plastic bending and then to plastic shear for small thicknesses and smooth chips are formed. The governing parameters are tool geometry, which is principally the wedge angle, and the material properties of elastic modulus, yield stress and fracture toughness. Friction can also be important. It is demonstrated that the cutting process may be quantified via these parameters, which could be useful in the study of cutting in biology.

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Effects of Imperfections in Heat Straightening Repair of Steel Beam Bridges

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198118780878 ◽

2018 ◽

Vol 2672 (41) ◽

pp. 165-176

Author(s):

Young Moo Sohn ◽

Amit H. Varma ◽

Robert J. Connor

Keyword(s):

Fracture Toughness ◽

Material Properties ◽

Heating Temperature ◽

Steel Bridge ◽

Hydraulic Actuator ◽

Force Magnitude ◽

Steel Material ◽

Damage Repair ◽

Maximum Heating Temperature ◽

Heat Straightening

A 40 ft. long two-span continuous steel bridge with two composite beams was constructed in the laboratory and subjected to damage followed by heat straightening repair. A36 steel section (W30 × 90) was used for the main girders (beams). Four spans (specimens) of the test bridge were statically damaged at each midspan using a hydraulic actuator, and subsequently repaired by applying Vee heats and restraining forces in the damaged region. Restraining force magnitude (corresponding to 0.4 Mp: 6.2 kips and 0.6 Mp: 9.5 kips), maximum heating temperature (800°F, 1200°F, and 1400°F), and the number of multiple damage-repair cycles (one and three cycles) were considered as the test parameters. The steel material properties were measured by taking samples from the repaired areas, and compared with undamaged steel material properties. Samples taken from specimens subjected to overheating (up to 1400°F) had similar structural properties and fracture toughness values as those taken from specimens subjected to normal heating (up to 1200°F). Specimens repaired with overstraining (0.6 Mp) combined with underheating (up to 800°F) required the largest number of heating cycles to fully repair the same damage. The fracture toughness of samples taken from specimens subjected to multiple (three times) damage-repair cycles was lower (decreased to about 84%) than the fracture toughness of samples taken from specimens subjected to only one damage-repair cycle. Therefore, multiple heat straightening repairs of a damaged beam should be performed with caution. With reference to serviceability performance for AASHTO HL-93 live load, the midspan deflections of beam specimens subjected to damage and heat straightening repair were comparable to those of undamaged beam specimens.

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Yielding and Fracture Toughness of Glass Microballoon-Filled Epoxy Composites

Polymers and Polymer Composites ◽

10.1177/096739110100900506 ◽

2001 ◽

Vol 9 (5) ◽

pp. 345-350 ◽

Cited By ~ 3

Author(s):

A.M. Zihlif ◽

G. Ragosta

Keyword(s):

Fracture Toughness ◽

Elastic Modulus ◽

Strain Rate ◽

Yield Stress ◽

Thermal Behaviour ◽

Filler Content ◽

Fracture Behaviour ◽

Rate Dependence ◽

Epoxy Composites ◽

Yielding Process

The yielding and fracture behaviour of epoxy/glass microballoon composites has been studied as a function of filler content, temperature and strain rate. No increase in elastic modulus, yield stress and fracture toughness was observed. The compressive yield stress of the composites showed strain rate dependence with more than one rate-activated yielding process. The fracture toughness parameters Gc and Kc were found to be temperature insensitive. The variations in the measured mechanical quantities are discussed in terms of the observed morphology and thermal behaviour of the epoxy composites.

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DILLIDUR 450V

Alloy Digest ◽

10.31399/asm.ad.sa0638 ◽

2011 ◽

Vol 60 (12) ◽

Keyword(s):

Fracture Toughness ◽

Wear Resistance ◽

Physical Properties ◽

Tensile Properties ◽

Room Temperature ◽

Surface Hardness ◽

Heat Treating ◽

Hot Working ◽

Resistant Steel ◽

Bend Strength

Abstract Dillidur 450V is a water hardened wear-resistant steel with surface hardness at room temperature of 420-480 HB. The steel is easy to weld and bend. Hot working is not recommended. This datasheet provides information on composition, physical properties, hardness, tensile properties, and bend strength as well as fracture toughness. It also includes information on wear resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-638. Producer or source: Dillinger Hütte GTS.

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NITRODUR 8524

Alloy Digest ◽

10.31399/asm.ad.sa0807 ◽

2017 ◽

Vol 66 (12) ◽

Keyword(s):

Fracture Toughness ◽

Fatigue Strength ◽

Tensile Properties ◽

High Temperatures ◽

High Surface ◽

Surface Hardness ◽

Operating Temperatures

Abstract NITRODUR 8524 (8CrMo16, 1.8524) is one of the Nitrodur family of nitriding steels that are used where high surface hardness and good fatigue strength are required and the material is also subjected to high temperatures. Nitrided surfaces maintain their hardness and strength at operating temperatures of up to approximately 500–550 deg C (932–1022 deg F). This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as casting and forming. Filing Code: SA-807. Producer or source: Schmolz + Bickenbach Group.

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Shear modulus and yield stress of foams: contribution of interfacial elasticity

Soft Matter ◽

10.1039/d0sm02246b ◽

2021 ◽

Vol 17 (14) ◽

pp. 3937-3944

Author(s):

Annika R. Völp ◽

Norbert Willenbacher

Keyword(s):

Elastic Modulus ◽

Block Copolymer ◽

Shear Modulus ◽

Yield Stress ◽

Protein Food ◽

General Correlation

A general correlation of foam shear modulus G0 and yield stress τy with the interfacial elastic modulus of foaming solutions in shear and dilation E∞ was found for surfactant, block-copolymer, protein, food, and particle-stabilized foams.

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