Dynamic Tensile Properties of Magnesium Nanocomposite

2012 ◽  
Vol 706-709 ◽  
pp. 780-785 ◽  
Author(s):  
Y.B. Guo ◽  
V.P.W. Shim ◽  
B. W. F. Tan
Keyword(s):  
Yield Stress ◽  
Strain Curve ◽  
Absorption Capacity ◽  
Tensile Behaviour ◽  
Al Alloy ◽  
Compression Tests ◽  
Energy Absorption Capacity ◽  
Dynamic Tension ◽  
Melt Deposition ◽  
Tension Compression Asymmetry

In this study, a Mg-6wt%Al alloy and its composite containing 0.22vol% Al2O3 nanoparticles are fabricated using a disintegrated melt deposition technique, and samples are subjected to quasi-static and dynamic tension. Compared to quasi-static loading, both materials exhibit significantly higher yield stresses and tensile strengths, much better ductility, and thus a higher energy absorption capacity under dynamic tension. In terms of nanoparticle addition, its influence on the mechanical properties are not notable; enhancement of the elastic modulus, yield stress and tensile strength are negligible, and there is a small reduction in ductility. The tensile behaviour obtained in this investigation was compared with results of previous compression tests, and significant tension-compression asymmetry in the response is observed. The tensile yield stress is noticeably larger than that in compression, and the profile of the stress-strain curve for tension differs from that for compression – it is convex upwards for tension, but concave upwards for compression. A possible reason for this asymmetry is the occurrence of twinning in compression and its absence in tension.

Transient Yielding during Compression Tests on ECAP’ed AA1050 Aluminium

2010 ◽  
Vol 667-669 ◽  
pp. 955-960 ◽  
Author(s):  
Bert Verlinden ◽  
En Ze Chen ◽  
Laurent Duchêne ◽  
Anne Marie Habraken
Keyword(s):  
Yield Stress ◽  
Kinematic Hardening ◽  
Strain Curve ◽  
Back Stress ◽  
Tensile Tests ◽  
Compression Tests ◽  
Lower Stress ◽  
Tension And Compression ◽  
Experimental Approaches ◽  
Tension Compression Asymmetry

In most papers dealing with tension and/or compression tests, the conventional yield stress is determined either by an offset method (usually 0.2% strain) or by back extrapolation from the stress-strain curve. In our experiments on ECAP’ed Aluminium a transient hardening saturation (THS) is always observed during the compression tests, but not during the tensile tests. This THS occurs at a significantly lower stress than the conventional yield stress. The aim of the present paper is to determine which the “real” start of yielding is. Two different experimental approaches have been adopted, confirming that the THS stage is exactly the yielding stage. This is not unimportant because it increases the tension-compression asymmetry and hence the back-stress and kinematic hardening. The reason for this different behaviour between tension and compression can be ascribed to a different change in strain path with respect to the ECAP deformation.

Effects of Strain Rate on Energy Absorption of High Strength TRIP Steel

2014 ◽  
Vol 552 ◽  
pp. 308-314
Author(s):  
Fei Xiang Yang ◽  
Chao Qun Zhu ◽  
Jun Jie Zhao ◽  
Yan Lin He ◽  
Lin Li
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
Trip Steel ◽  
Static Condition ◽  
Absorption Capacity ◽  
Gradual Transition ◽  
Absorption Properties ◽  
Energy Absorption Capacity ◽  
Dynamic Tension ◽  
Dp Steel

In this paper, the energy absorption properties of 600 MPa and 800MPa grade TRIP and DP steels under different strain rates were investigated. It was shown that the deformation of dynamic specimens concentrated in parallel section under quasi-static stretching, and the strain rate had nothing to do with the energy absorption of these four steel. In the dynamic tension, the TRIP steel had a better energy absorption capacity than it in the quasi-static condition. However, the energy absorption properties of DP steel were not the case. And with the increasing of the strain rate, the energy absorption of these four steel decreased. It was because that instead of “gradual transition”, the transformation of retained austenite changed to “instantaneous transition” in dynamic tension. It made the energy absorption become smaller than it in static tension. Meanwhile, the ductility and the energy absorption capacity of the DP steel were improved, which effected by the adiabatic temperature rise. Owing to suppression of plastic deformation of these steel in dynamic tension, the energy absorption capacity of these four steel decreased with the increasing of strain rate.

Increasing Initial Yield Stress at Small Length Scales

2003 ◽  
Vol 778 ◽  
Author(s):  
I. Spary ◽  
A.J. Bushby ◽  
N.M. Jennett ◽  
G.M. Pharr
Keyword(s):  
Yield Stress ◽  
Size Effects ◽  
Strain Curve ◽  
Compression Tests ◽  
Small Length ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Length Scales ◽  
Initial Yield Stress ◽  
Initial Yield

AbstractPlasticity size effects are well known in a wide variety of situations where either the material microstructure or a strain gradient exist at small length scales. Several theories have been developed to describe changes in the work hardening behaviour under these conditions but none that predict a change in the initial yield stress. Careful studies by Chaudhri et al and Pharr et al have unambiguously demonstrated plasticity size effects in ductile metals. In those experiments indentation stress-strain curves were generated using spherical indenters with radii ranging from a few micrometres to several hundred micrometres and these were compared to data from conventional compression tests. Large radius indenters produced a single indentation stress-strain curve independent of indenter radius with a power law hardening coefficient equivalent to that in the compression tests. However, the indentation stress-strain curves appeared at progressively higher pressures for smaller radius indenters. In this paper we model those experiments using finite element analysis methods. By inputting the uniaxial stress-strain data to the model (effectively, using von Mises criterion) the indentation stress-strain curves for the macro size indenters are reproduced. However, the model shows no length scale dependence for any size of indenter. We show that by off-setting the compression stress-strain curve by increasing the initial yield stress and inputting this data to the model, the indentation behaviour of the smaller radius indenters can be modelled. The increase in yield stress with decreasing indenter radius is demonstrated for Cu, Wand Ir and is shown to be consistent with the initiation of yielding over a finite volume.

Mechanical Properties and Energy Absorption Capability of Closed-Cell Al Alloy Foam

2012 ◽  
Vol 450-451 ◽  
pp. 325-328 ◽  
Author(s):  
Wei Han Yang ◽  
Zhan Guang Wang ◽  
Ping Cai ◽  
Jing Zhi Hu
Keyword(s):  
Energy Absorption ◽  
Engineering Application ◽  
Strain Curve ◽  
Al Alloy ◽  
Compression Tests ◽  
Theoretical Support ◽  
Closed Cell ◽  
Al Foam ◽  
Collapse Region ◽  
Al Alloy Foam

Based on compression tests of closed-cell Al alloy foam measured, mchanical properties and energy absorption capability had been investigated. The compressive stress-strain curve of closed-cell Al foam consists of three distinct regions, i.e., the linear elasticity region, the plastic collapse region or brittle crushing region, and the densification region. Formula on energy absorption capability of closed-cell Al alloy foam was presented, which could provide theoretical support for its engineering application.

ALUMINUM ALLOY 201.0

Alloy Digest ◽  
1995 ◽  
Vol 44 (7) ◽  
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Physical Properties ◽  
High Strength ◽  
Heat Treating ◽  
Absorption Capacity ◽  
Casting Alloy ◽  
Permanent Mold ◽  
Energy Absorption Capacity ◽  
Temperature Performance

Abstract ALUMINUM ALLOY 201.0 is a structural casting alloy available as sand, permanent mold and investment castings. It is used in structural casting members, applications requiring high tensile and yield strengths with moderate elongation, and where high strength and energy-absorption capacity are needed. This datasheet provides information on composition, physical properties, and elasticity as well as creep and fatigue. It also includes information on high temperature performance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: AL-336. Producer or source: Various aluminum companies.

Quasi-static Compressive Properties and Behavior of Single-cell Miura Origami Column Fabricated by 3D Printed PLA Material

2020 ◽  
Vol 3 (2) ◽  
pp. 66-73
Author(s):  
Farid Triawan ◽  
Geraldy Cahya Denatra ◽  
Djati Wibowo Djamari
Keyword(s):  
Single Cell ◽  
Peak Stress ◽  
Absorption Capacity ◽  
Compression Tests ◽  
Compressive Properties ◽  
Folding Pattern ◽  
Column Structure ◽  
Thin Walled ◽  
And Behavior ◽  
Initial Peak

The study of a thin-walled column structure has gained much attention due to its potential in many engineering applications, such as the crash box of a car. A thin-walled square column usually exhibits high initial peak force, which may become very dangerous to the driver or passenger. To address this issue, introducing some shape patterns, e.g., origami folding pattern, to the column may become a solution. The present work investigates the compressive properties and behavior of a square box column structure which adopts the Miura origami folding pattern. Several test pieces of single-cell Miura origami column with varying folding angle and layer height are fabricated by a 3D printer. The filament is made of Polylactic Acid (PLA), which is a brittle material. Then, compression tests are carried out to understand its compressive mechanical properties and behavior. The results show that introducing a Miura origami pattern to form a thin-walled square column can dramatically lower down the initial peak stress by 96.82% and, at the same time, increase its ductility, which eventually improves the energy absorption capacity by 61.68% despite the brittle fracture behavior.

scholarly journals Electrical Performance of Polymer-Insulated Rail Brackets of DC Transit Subjected to Lightning Induced Overvoltage

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1684
Author(s):  
Farah Asyikin Abd Rahman ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Ungku Anisa Ungku Amirulddin ◽  
Miszaina Osman
Keyword(s):  
Performance Comparison ◽  
Absorption Capacity ◽  
Electrical Performance ◽  
Sensitivity Analyses ◽  
Lightning Strike ◽  
Rail Transit ◽  
Energy Absorption Capacity ◽  
Urban Transit ◽  
Residual Voltage ◽  
Reinforced Plastic

The fourth rail transit is an interesting topic to be shared and accessed by the community within that area of expertise. Several ongoing works are currently being conducted especially in the aspects of system technical performances including the rail bracket component and the sensitivity analyses on the various rail designs. Furthermore, the lightning surge study on railway electrification is significant due to the fact that only a handful of publications are available in this regard, especially on the fourth rail transit. For this reason, this paper presents a study on the electrical performance of a fourth rail Direct Current (DC) urban transit affected by an indirect lightning strike. The indirect lightning strike was modelled by means of the Rusck model and the sum of two Heidler functions. The simulations were carried out using the EMTP-RV software which included the performance comparison of polymer-insulated rail brackets, namely the Cast Epoxy (CE), the Cycloaliphatic Epoxy A (CEA), and the Glass Reinforced Plastic (GRP) together with the station arresters when subjected by 30 kA (5/80 µs) and 90 kA (9/200 µs) lightning currents. The results obtained demonstrated that the GRP material has been able to slightly lower its induced overvoltage as compared to other materials, especially for the case of 90 kA (9/200 µs), and thus serves better coordination with the station arresters. This improvement has also reflected on the recorded residual voltage and energy absorption capacity of the arrester, respectively.

scholarly journals Investigation of Energy-Absorbing Properties of a Bio-Inspired Structure

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 881
Author(s):  
Adrian Dubicki ◽  
Izabela Zglobicka ◽  
Krzysztof J. Kurzydłowski
Keyword(s):  
Absorption Capacity ◽  
Compression Tests ◽  
Element Analysis ◽  
Lightweight Structures ◽  
New Energy ◽  
Absorbing Material ◽  
Lightweight Structure ◽  
3D Printed ◽  
Deformation Force ◽  
Energy Absorbing

Numerous engineering applications require lightweight structures with excellent absorption capacity. The problem of obtaining such structures may be solved by nature and especially biological structures with such properties. The paper concerns an attempt to develop a new energy-absorbing material using a biomimetic approach. The lightweight structure investigated here is mimicking geometry of diatom shells, which are known to be optimized by nature in terms of the resistance to mechanical loading. The structures mimicking frustule of diatoms, retaining the similarity with the natural shell, were 3D printed and subjected to compression tests. As required, the bio-inspired structure deformed continuously with the increase in deformation force. Finite element analysis (FEA) was carried out to gain insight into the mechanism of damage of the samples mimicking diatoms shells. The experimental results showed a good agreement with the numerical results. The results are discussed in the context of further investigations which need to be conducted as well as possible applications in the energy absorbing structures.

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

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