scholarly journals Mechanical Behaviour and Failure Mode of High Interstitially Alloyed Austenite under Combined Compression and Cyclic Torsion

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 157
Author(s):  
Timothy Ngeru ◽  
Dzhem Kurtulan ◽  
Ahmet Karkar ◽  
Stefanie Hanke
Keyword(s):  
Compressive Strain ◽  
Decisive Role ◽  
Axial Direction ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Shear Stresses ◽  
Multiaxial Stress ◽  
Complex Load ◽  
Static Compression ◽  
Stress States

multiaxial stress states frequently occur in technical components and, due to the multitude of possible load situations and variations in behaviour of different materials, are to date not fully predictable. This is particularly the case when loads lie in the plastic range, when strain accumulation, hardening and softening play a decisive role for the material reaction. This study therefore aims at adding to the understanding of material behaviour under complex load conditions. Fatigue tests conducted under cyclic torsional angles (5°, 7.5°, 10° and 15°), with superimposed axial static compression loads (250 MPa and 350 MPa), were carried out using smooth specimens at room temperature. A high nitrogen alloyed austenitic stainless steel (nickel free), was employed to determine not only the number of cycles to failure but particularly to aid in the understanding of the mechanical material reaction to the multiaxial stresses as well as modes of crack formation and growth. Experimental test results indicate that strain hardening occurs under the compressive strain, while at the same time cyclic softening is observable in the torsional shear stresses. Furthermore, the cracks’ nature is unusual with multiple branching and presence of cracks perpendicular in direction to the surface cracks, indicative of the varying multiaxial stress states across the samples’ cross section as cross slip is activated in different directions. In addition, it is believed that the static compressive stress facilitated the Stage I (mode II) crack to change direction from the axial direction to a plane perpendicular to the specimen’s axis.

scholarly journals Calibrating a New Constitutive Tension Model to Extract a Simplified Nonlinear Sectional Analysis of Reinforced Concrete Beams

2021 ◽  
Vol 11 (5) ◽  
pp. 2292
Author(s):  
Alaaeldin Abouelleil ◽  
Hayder A. Rasheed
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Compressive Strain ◽  
Design Criterion ◽  
Reinforced Concrete Beams ◽  
Secondary Outcome ◽  
Shear Stresses ◽  
Structural Members ◽  
Flexural Member ◽  
Smeared Crack

Nonlinear analysis of structural members is vital to understand the behavior and the response of reinforced concrete members. Even though most design procedures concentrate on the ultimate stage of response towards the end of the post-yielding zone as the decisive design criterion, the structural members usually function at the service load levels within the post-cracking zone. Therefore, cracking is a critical aspect of concrete behavior that affects the overall response of reinforced concrete beams. The initiation and the propagation of the cracks are affected directly by the tension and shear stresses in the beam. In flexural beams, the tensile stresses dominate the crack onset and its growth. Cracks in reinforced concrete flexural beams leave non-cracked regions in between the cracked sections. In order to apply a consistent analysis strategy, the smeared crack approach averages the behavior of these different cracked sections and uncracked in between regions to generate an accurate global response of the entire beam. This study presents a numerical constitutive tensile model that captures the complete tensile response of the reinforced concrete flexural member, in terms of averaged/smeared crack response. As a second step, this model was examined against a large pool of experimental data to validate its accuracy. Overall, the main objective of this study is to develop a representative constitutive tensile model for reinforced concrete flexural members and validate its accuracy against experimental results. The full nonlinear sectional response is analytically realized, based on the assumed trilinear moment–curvature response and the assumed trilinear moment–extreme fiber compressive strain response. This is considered as the secondary outcome of the present study.

Cyclic Mechanical Properties of 16MnR Welded Joint under Constant

2011 ◽  
Vol 197-198 ◽  
pp. 1658-1661
Author(s):  
Ying Xiong ◽  
Han Ying Zheng
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Endurance Limit ◽  
Welded Joint ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Test Results ◽  
Control Test ◽  
Strain Control ◽  
Fatigue Endurance

Fatigue tests are carried out for 16MnR welded joint under constant strain control. Test results reveal that 16MnR weld metal exhibits characteristic of cyclic softening and non-masing obviously. The strain–life curve can be best described by the three-parameter equation. It shows the fatigue endurance limit in the heat-affecting zone (HAZ) of welded joint is lower than that in the weld metal.

Mechanical compression alters proteoglycan deposition and matrix deformation around individual cells in cartilage explants

1998 ◽  
Vol 111 (5) ◽  
pp. 573-583
Author(s):  
T.M. Quinn ◽  
A.J. Grodzinsky ◽  
M.D. Buschmann ◽  
Y.J. Kim ◽  
E.B. Hunziker
Keyword(s):  
Morphological Changes ◽  
Dynamic Compression ◽  
Compressive Strain ◽  
Cell Length ◽  
Cartilage Explants ◽  
Proteoglycan Synthesis ◽  
Length Scale ◽  
Mechanical Compression ◽  
Static Compression ◽  
Associated Matrix

We have used new techniques of cell-length scale quantitative autoradiography to assess matrix synthesis, deposition, and deformation around individual chondrocytes in mechanically compressed cartilage explants. Our objectives were to: (1) quantify the effects of static and dynamic compression on the deposition of newly synthesized proteoglycans into cell-associated and further-removed matrices; (2) measure cell-length scale matrix strains and morphological changes of the cell and matrix associated with tissue compression; and (3) relate microscopic physical stimuli to changes in proteoglycan synthesis as functions of compression level and position within mechanically compressed explants. Results indicate a high degree of structural organization in the extracellular matrix, with the pericellular matrix associated with the most rapid rates of proteoglycan deposition, and greatest sensitivity to mechanical compression. Static compression could stimulate directional deposition of secreted proteoglycans around chondrocytes, superimposed on an inhibition of proteoglycan synthesis; these events followed trends for compressive strain in the cell-associated matrix. Conversely, proteoglycan synthesis and pericellular deposition was stimulated by dynamic compression. Results suggest that cell-matrix interactions in the cell-associated matrix may be a particularly important aspect of the chondrocyte response to mechanical compression, possibly involving macromolecular transport limitations and morphological changes associated with fluid flow and local compaction of the matrix around cells.

scholarly journals Multiaxial fatigue study on steel transversal attachments under constant amplitude proportional and non-proportional loadings

2018 ◽  
Vol 165 ◽  
pp. 16007
Author(s):  
Martin Garcia ◽  
Claudio A. Pereira Baptista ◽  
Alain Nussbaumer
Keyword(s):  
Fatigue Life ◽  
High Strength ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Life Assessment ◽  
Experimental Program ◽  
Proportional Loading ◽  
Load Carrying ◽  
Stress States ◽  
Experimental Values

In this study, the multiaxial fatigue strength of full-scale transversal attachment is assessed and compared to original experimental results and others found in the literature. Mild strength S235JR steel is used and an exploratory investigation on the use of high strength S690QL steel and the effect of non-proportional loading is presented. The study focuses on non-load carrying fillet welds as commonly used in bridge design and more generally between main girders and struts. The experimental program includes 33 uniaxial and multiaxial fatigue tests and was partially carried out on a new multiaxial setup that allows proportional and non-proportional tests in a typical welded detail. The fatigue life is then compared with estimations obtained from local approaches with the help of 3D finite element models. The multiaxial fatigue life assessment with some of the well-known local approaches is shown to be suited to the analysis under multiaxial stress states. The accuracy of each models and approaches is compared to the experimental values considering all the previously cited parameters.

Fatigue Capacity of Stiffener to Web Frame Connections

2009 ◽  
Author(s):  
Torbjo̸rn Lindemark ◽  
Inge Lotsberg ◽  
Joong-Kyoo Kang ◽  
Kwang-Seok Kim ◽  
Narve Oma
Keyword(s):  
Fatigue Test ◽  
Test Data ◽  
Large Scale ◽  
Fatigue Tests ◽  
Life Assessment ◽  
Shear Stresses ◽  
Test Model ◽  
The Difference ◽  
Marine Engineering ◽  
Plate Connections

Daewoo Shipbuilding & Marine Engineering Co., Ltd. (DSME), StatoilHydro and DNV established a common project to investigate the reason for the difference between calculated fatigue lives and the in-service experience and to assess the fatigue capacity of stiffener web connections subjected mainly to web frame shear stresses. The main objective of the work was to establish fatigue test data and perform numerical analysis of collar plate connections in order to provide improved confidence in analysis methodology for fatigue life assessment. Large scale fatigue tests of different types of connections were carried out to obtain fatigue test data of collar plate connections. Finite element analyses were carried out for comparison with fatigue test data and with measured stresses on the test model. Based on this work recommendations on fatigue design analysis of connections between stiffeners and web frames have been derived. The background for this is presented in this paper.

Behavior of Concrete under Multiaxial Stress States

1980 ◽  
Vol 106 (6) ◽  
pp. 1383-1403 ◽  
Author(s):  
Kurt Berlin Gerstle ◽  
Roger M. Zimmerman ◽  
Helmut Winkler ◽  
Leonard A. Traina ◽  
Michael A. Taylor ◽  
...  
Keyword(s):  
Multiaxial Stress ◽  
Stress States

Mechanical Behavior of Buried Pipeline Crossing Thaw Settlement Zone

2021 ◽  
Author(s):  
Rui Xie ◽  
Prof. Jie Zhang
Keyword(s):  
Mechanical Behavior ◽  
Axial Strain ◽  
Compressive Strain ◽  
High Stress ◽  
Axial Direction ◽  
Soil Parameters ◽  
Buried Pipeline ◽  
Obvious Effect ◽  
Thaw Settlement ◽  
Pipeline Crossing

Abstract Thaw settlement is one of main reason caused pipeline failure crossing cold region. Mechanical behavior of buried pipeline crossing thaw settlement zone is investigated. Effects of pipeline and soil parameters on the buried pipeline were discussed. The results show that the high stress area and the max axial strain of the pipeline is at the edge of the thaw settlement zone. The upper surface of the pipeline is tensile strain, while the lower surface is compressive strain. The max ovality of pipeline near the edge of thaw settlement zone tends to oval. The pipeline axial strain, ovality and displacement decreases with the increasing of pipeline wall thickness, while the change of high stress area is not obvious. The high stress area and ovality decrease with the increasing of pipeline diameter, while the high stress area is expanded along the axial direction, but axial strain decreases slightly. The high stress area, axial strain, ovality and displacement of pipeline decrease with the buried depth increases. With the internal pressure increases, the stress and axial strain of pipeline increase, but the ovality decreases. The soil`s elasticity modulus has no obvious effect on pipeline`s stress, axial strain and displacement, but it can affect ovality slightly.

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