scholarly journals Change of Specimen Temperature during the Monotonic Tensile Test and Correlation between the Yield Strength and Thermoelasto-Plastic Limit Stress on the Example of Aluminum Alloys

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 13
Author(s):  
Adam Lipski
Keyword(s):  
Yield Strength ◽  
Tensile Test ◽  
Tensile Tests ◽  
Plastic Limit ◽  
Temperature Changes ◽  
Offset Yield Strength ◽  
Specimen Temperature ◽  
Thermographic Camera ◽  
Chatelier Effect ◽  
Limit Stress

This paper presents an attempt to generalize the description of the course of specimen temperature changes during the tensile test and to connect the value of the thermoelasto-plastic limit stress with the value of a clear (physical) or proof strength (offset yield strength) on the example of tests of the following aluminum alloy sheets used in Poland for airplane structures: 2024-T3 and D16 in three grades: D16ATV, D16CzATV, and D16UTV. A thermographic camera was used for specimen surface temperature measurement during the tensile test. The Portevine–Le Chatelier effect (the so-called PLC effect) was observed for tests of specimens cut from sheet plates, which was strongly reflected in the temperature fluctuations. The course of temperature change during tensile tests was divided into four characteristic stages related to the occurrence of a clear or offset yield strength. It was found that if there is a clear yield strength, the value of the thermoelasto-plastic limit stress was greater than this yield strength. If there was an offset yield strength, the value of the thermoelasto-plastic limit stress was lower than this yield strength. The differences in the aforementioned values of individual yield strengths did not exceed several percent. Thus, it can be concluded that the thermoelasto-plastic limit stress determined on the basis of the course of specimen temperature changes during the tensile test is well correlated with the value of the yield strength of the material.

Analysis of the Influence of Injection Process Parameters of Polymer Blends from Printers

2018 ◽  
Vol 930 ◽  
pp. 248-253
Author(s):  
Eduardo Luís Schneider ◽  
José Victor Rebechi Valle Gonçalves ◽  
Ana Paula Adam ◽  
Daniela Muller de Quevedo ◽  
Luiz Carlos Robinson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Tensile Test ◽  
Process Parameters ◽  
Flame Retardants ◽  
Mechanical Characterization ◽  
Tensile Tests ◽  
Injection Process ◽  
The World ◽  
Different Levels

Among the 40 million tons/year of e-waste discarded in the world, the recycling of polymers depends on the correct separation in disassembly as well as control of fluidity during processing. The objective of this study is to analyze the feasibility of HIPS blends recycling with other main polymers present in printers, through the analysis of the influence of pressure and speed parameters of injection to subsequently perform tensile tests for mechanical characterization. For this purpose, post-consumption polymers from disassembled printers were separated for analysis and comparison of HIPS-90%/PS-10% blend with HIPS-100%, which were injected into a mold with geometry of test specimens for tensile test, complying with ASTM standard D638-14, employing variations in pressure and speed and maintaining constant temperature. To identify the influence of levels of pressure between 45 and 60 bar and speed between 45 and 60 mm/min in yield point and elongation of the material a two-way ANOVA without replication was applied. When comparing the different levels of pressure and speed considered and evaluated in relation to the material composition, there were no significant differences between the levels, for both yield strength and for elongation. It was verified a variation on the mechanical properties of the PSHI and PS blend in relation to the pure PSHI, probably due to the amount of brominated flame retardants and elastomers present in PSHI from printers.

Regularities and properties of instrumented indentation diagrams obtained by ball-shaped indenter

2020 ◽  
Vol 86 (5) ◽  
pp. 43-51
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
P. V. Volkov ◽  
D. A. Zhgut
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Elastoplastic Deformation ◽  
Elastic Limit ◽  
Tensile Tests ◽  
Indentation Load ◽  
International Standards ◽  
Instrumented Indentation ◽  
Indentation Methods ◽  
Special Points

The history of appearance and the current state of instrumented indentation are briefly described. It is noted that the materials instrumented indentation methods using a pyramid and ball indenters are actively developing and are currently regulated by several Russian and international standards. These standards provide formulas for calculating the Young’s modulus and hardness at maximum indentation load. Instrumented indentation diagrams «load F – displacement α» of a ball indenter for metallic materials were investigated. The special points on the instrumented indentation diagrams «F – α» loading curves in the area of elastic into elastoplastic deformation transition, and in the area of stable elastoplastic deformation are revealed. A loading curve area with the load above which the dF/dα begins to decrease is analyzed. A technique is proposed for converting «F – α» diagrams to «unrestored Brinell hardness HBt – relative unrestored indent depth t/R» diagrams. The elastic and elastoplastic areas of «HBt – t/R» diagrams are described by equations obtained analytically and experimentally. The materials strain hardening parameters during ball indentation in the area of elastoplastic and plastic deformation are proposed. The similarity of «HBt – t/R» indentation diagram with the «stress σ – strain δ» tensile diagrams containing common zones and points is shown. Methods have been developed for determining hardness at the elastic limit, hardness at the yield strength, and hardness at the ultimate strength by instrumented indentation with the equations for their calculation. Experiments on structural materials with different mechanical properties were carried out by instrumented indentation. The values of hardness at the elastic limit, hardness at the yield strength and hardness at the ultimate strength are determined. It is concluded that the correlations between the elastic limit and hardness at the elastic limit, yield strength and hardness at the yield strength, ultimate tensile strength and hardness at the ultimate strength is more justified, since the listed mechanical characteristics are determined by the common special points of indentation diagrams and tensile tests diagrams.

Shakedown and Limit Analysis of Kinematic Hardening Piping Elbows Under Internal Pressure and Bending Moments

2021 ◽  
Author(s):  
Heng Peng ◽  
Yinghua Liu
Keyword(s):  
Yield Strength ◽  
Internal Pressure ◽  
Limit Analysis ◽  
Kinematic Hardening ◽  
Limit Load ◽  
Bending Moments ◽  
Plastic Limit ◽  
Plastic Limit Load ◽  
Interaction Curves ◽  
Shakedown Limit

Abstract In this paper, the Stress Compensation Method (SCM) adopting an elastic-perfectly-plastic (EPP) material is further extended to account for limited kinematic hardening (KH) material model based on the extended Melan's static shakedown theorem using a two-surface model defined by two hardening parameters, namely the initial yield strength and the ultimate yield strength. Numerical analysis of a cylindrical pipe is performed to validate the outcomes of the extended SCM. The results agree well with ones from literature. Then the extended SCM is applied to the shakedown and limit analysis of KH piping elbows subjected to internal pressure and cyclic bending moments. Various loading combinations are investigated to generate the shakedown limit and the plastic limit load interaction curves. The effects of material hardening, elbow angle and loading conditions on the shakedown limit and the plastic limit load interaction curves are presented and analysed. The present method is incorporated in the commercial finite element simulation software and can be considered as a general computational tool for shakedown analysis of KH engineering structures. The obtained results provide a useful information for the structural design and integrity assessment of practical piping elbows.

Correlation among Microstructure, Texture, and Properties along the Thickness Direction in As-Hot-Rolled and As-Solution-Quenched Al7055 Thick Plates

2021 ◽  
Vol 1026 ◽  
pp. 65-73
Author(s):  
Kai Zhu ◽  
Hong Wei Yan
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Tensile Tests ◽  
Rolled Plate ◽  
Uniaxial Tensile ◽  
Thickness Direction ◽  
Electron Backscattered Diffraction ◽  
Thick Plates ◽  
Aluminum Plates ◽  
Hot Rolled

Both microstructure inhomogeneity and mechanical property diversity along the thickness direction in rolled thick aluminum plates have been considered to have a remarkable impact on the performance and properties of the products made from the plates. In this study, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) characterizations of microstructure and texture types along the thickness directions of Al7055 thick plate specimens prepared using two conditions, hot-rolling and solution-quenching, were performed. To examine the mechanical properties, uniaxial tensile tests were also carried out on specimens machined from both types of thick plates, using a layered strategy along the thickness direction. The results indicate that both the microstructure and mechanical properties are inhomogeneous under the two conditions. Furthermore, it is evident that there is a hereditary relationship between the mechanical properties of the two plates—areas with higher yield strength in the as-hot-rolled plate correspond to areas with the higher yield strength in the as-solution-quenched plate

Study Regarding the Influence of the Printing Orientation Angle on the Mechanical Behavior of Parts Manufactured by Material Jetting

2021 ◽  
Vol 58 (3) ◽  
pp. 198-209
Author(s):  
Vasile Cojocaru ◽  
Doina Frunzaverde ◽  
Dorian Nedelcu ◽  
Calin-Octavian Miclosina ◽  
Gabriela Marginean
Keyword(s):  
Additive Manufacturing ◽  
Rapid Prototyping ◽  
Tensile Test ◽  
Mechanical Behavior ◽  
Process Parameters ◽  
Orientation Angle ◽  
Tensile Tests ◽  
Anisotropic Behavior ◽  
Optimization Of Process Parameters ◽  
Printed Materials

Initially developed as a rapid prototyping tool for project visualization and validation, the recent development of additive manufacturing (AM) technologies has led to the transition from rapid prototyping to rapid manufacturing. As a consequence, increased attention has to be paid to the mechanical, chemical and physical properties of the printed materials. In mechanical engineering, the widespread use of AM technologies requires the optimization of process parameters and material properties in order to obtain components with high, repeatable and time-stable mechanical properties. One of the main problems in this regard is the anisotropic behavior of components made by additive manufacturing, determined by the type of material, the 3D printing technology, the process parameters and the position of the components in the printing space. In this paper the influence of the printing orientation angle on the tensile behavior of specimens made by material jetting is investigated. The aim was to determine if the positioning of components at different angles relative to the X-axis of the printer (and implicitly in relation to the multijet printing head) contributes to anisotropic behavior. The material used was a photopolymer with a mechanical strength between 40 MPa and 55 MPa, according to the producer. Four sets of tensile test specimens were manufactured, using flat build orientation and positioned on the printing table at angles of 0˚, 30˚, 60˚ and 90˚ to the X-axis of the printer. Comparative analysis of the mechanical behavior was carried out by tensile tests and microscopic investigations of the tensile test specimens fracture surfaces.

Influence of Severe Plastic Deformation on the PLC Effect and Mechanical Properties in Al 5XXX Alloy

2006 ◽  
Vol 114 ◽  
pp. 171-176 ◽  
Author(s):  
Joanna Zdunek ◽  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
True Strain ◽  
Tensile Tests ◽  
Size Reduction ◽  
Hydrostatic Extrusion ◽  
Stress Strain ◽  
Chatelier Effect

In this work, Al-Mg-Mn-Si alloy (5483) in the as-received and severe plastically deformed states was used. Plastic deformation was carried out by hydrostatic extrusion, and three different true strain values were applied 1.4, 2.8 and 3.8. All specimens were subjected to tensile tests and microhardness measurements. The investigated material revealed an instability during plastic deformation in the form of serration on the stress-strain curves, the so called Portevin-Le Chatelier effect It was shown that grain size reduction effected the character of the instability.

Tensile Properties and Fracture Behavior of SiCp/AC4CH Composite at Loading Velocities of up to 10m/s

2004 ◽  
Vol 449-452 ◽  
pp. 305-308
Author(s):  
Lei Wang ◽  
Toshiro Kobayashi ◽  
Chun Ming Liu
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Tensile Deformation ◽  
Optical Microscope ◽  
Fracture Elongation ◽  
Before And After

Tensile test at loading velocities up to 10 m·s-1(strain rate up to 3.2x102s-1) was carried out forr SiCp/AC4CH composite and AC4CH alloy. The microstructure of the composite before and after tensile deformation was carefully examined with both optical microscope and SEM. The experimental results demonstrated that the ultimate tensile strength (UTS) and yield strength (YS) increase with increasing loading velocity up to 10 m·s-1. Comparing with AC4CH alloy, the fracture elongation of the composite is sensitivity with the increasing strain rate. The YS of both the composite and AC4CH alloy shows more sensitive than that of the UTS with the increasing strain rate, especially in the range of strain rate higher than 102s-1.

Mechanical Properties of Flat Braided Composites With a Circular Hole

1999 ◽  
Author(s):  
Takeru Ohki ◽  
Shinya Ikegaki ◽  
Ken Kurasiki ◽  
Hiroyuki Hamada ◽  
Masaharu Iwamoto
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Circular Hole ◽  
Fracture Behavior ◽  
Fatigue Property ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Braided Composites ◽  
Static Tensile ◽  
The One

Abstract In this study, fracture behavior and strength in the flat braided bar with a circular hole were investigated by static and fatigue test. Two type of specimens were prepared. They are a braided flat bar with an integrally-formed braided hole and a braided flat bar with a machined hole. Moreover, we also examined a specimen that had a metal pin inserted at the circular hole. This specimen was subjected to a static tensile test. The results of the tensile tests indicate that the strength of the flat bar with a braided hole was larger than that of the one with the machined hole. Furthermore, from the results of the fatigue tests, the flat bar with the braided hole showed higher fatigue property than that of the one with the machined hole.

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