Experimental and Numerical Investigation of Grooved Thin-Walled Steel Cylinders Under Axial Compression

2010 ◽  
Author(s):  
Arshia Pakizehkar ◽  
Mirhamed Sarkarfarshi ◽  
Abolfazl Masomi
Keyword(s):  
Axial Compression ◽  
Peak Load ◽  
Axial Loading ◽  
Element Model ◽  
Displacement Curve ◽  
Fe Model ◽  
Absorbed Energy ◽  
Explicit Finite Element ◽  
Thin Walled ◽  
Load Displacement

In this study, axial compression behavior of grooved thin-walled steel cylinders is investigated using experimental and numerical methods. Circumferential grooves are generated by means of a special forming tools and the effect of interval between the grooves and their total number on the load-displacement curve, energy absorption-displacement curves and initial buckling load are investigated. It is revealed that having circumferential grooves on the tubes can decrease the initial peak load in load-displacement curve and also increase the amount of absorbed energy. Then explicit Finite Element Model of aforementioned grooved tubes under axial loading are generated using ANSYS software and solved utilizing LSDYNA solver. Result of the FE models (containing the amount of absorbed energy, the peak load and the load-displacement curve during axial compression) are validated by comparing them with those of experimental test. The outcome of comparisons confirms the FE model to be in a good agreement with experimental results.

scholarly journals Axial Compression Behavior of Circular Concrete-Filled High-Strength Thin-Walled Steel Tubular Columns with Out-of-Code D/t Ratios

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jun-Xin Li ◽  
Jian-Tao Wang ◽  
Qing Sun ◽  
Yan-Ru Wu ◽  
Shi-Ming Zhou ◽  
...  
Keyword(s):  
Axial Compression ◽  
Full Range ◽  
High Strength ◽  
Displacement Curve ◽  
Fe Model ◽  
Range Analysis ◽  
Cross Sectional ◽  
Compression Behavior ◽  
Thin Walled ◽  
Cfst Columns

This paper systematically investigated the axial compression behavior of circular concrete-filled high-strength thin-walled steel tubular (CFHTST) columns with out-of-code diameter-to-thickness (D/t) ratios. The axial compression test was first conducted to examine the failure mode, load-displacement curves, and composite mechanism effect. The finite element (FE) model was thereafter established to perform full-range analysis on the load versus displacement curve as well as the interaction behavior, where the parametric study was performed to investigate the influences of the material strengths and geometric sizes. Subsequently, the applicability of typical design methods was evaluated, and a revised equation for determining strain εscy corresponding to ultimate strength was established to assess the plastic deformation capacity of CFHTST columns. Finally, a theoretical model for calculating axial bearing capacity was derived based on unified twin-shear strength theory by considering the influence of intermediate principal stress. The research results indicate that a relatively high confine effect can be guaranteed for CFHTST columns under out-of-code D/t ratios, given that the ratio Nu/Nnom between the measured capacity (Nu) and nominal cross-sectional capacity (Nnom) mainly distributes within 1.179∼1.292; the full-range analysis reflects that the axial load-deformation curve can be distinguished by four various loading stages; the scope b = 0.3∼0.55 of intermediate stress coefficient is generally suggested for predicting axial strength of circular CFST columns within an error of ±5%. The abovementioned study can provide the meaningful design reference for the analysis and application of CFHTST columns.

Thermo-mechanical analysis of train wheel-rail contact using a novel finite-element model

2020 ◽  
Vol 72 (5) ◽  
pp. 687-693
Author(s):  
Liuqing Yang ◽  
Ming Hu ◽  
Deming Zhao ◽  
Jing Yang ◽  
Xun Zhou
Keyword(s):  
Finite Element ◽  
Peer Review ◽  
Frictional Heating ◽  
Element Model ◽  
Mechanical Analysis ◽  
Partial Slip ◽  
Computational Time ◽  
Fe Model ◽  
Content Type ◽  
Explicit Finite Element

Purpose The purpose of this paper is to develop a novel method for analyzing wheel-rail (W-R) contact using thermo-mechanical measurements and study the effects of heating on the characteristics of W-R contact under different creepages. Design/methodology/approach This study developed an implicit-explicit finite element (FE) model which could solve both partial slip and full sliding problems by setting different angular velocities on the wheels. Based on the model, four material types under six different creepages were simulated. Findings The results showed that frictional heating significantly affected the residual stress distribution under large creepage conditions. As creepage increased, the temperature of the wheel tread and rail head rose and the peak value was located at the trailing edge of the contact patch. Originality/value The proposed FE model could reduce computational time and thus cost to about one-third of the amount commonly found in previous literature. Compared to other studies, these results are in good agreement and offer a reasonable alternative method for analyzing W-R contact under various conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0298

scholarly journals MODELING OF MONOCRYSTALLINE MAGNESIUM MICROBEAM BENDING

2018 ◽  
Vol 15 ◽  
pp. 69-73
Author(s):  
Jiří Němeček ◽  
Jan Maňák ◽  
Jiří Němeček
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Deformation Energy ◽  
Displacement Curve ◽  
Fe Model ◽  
Cantilever Beams ◽  
Elastoplastic Behavior ◽  
Load Displacement ◽  
Micro Cantilever

This paper presents a numerical simulation of a micro-scale experiment on a magnesium alloy. Micro cantilever beams were fabricated using Focused Ion Beam technology in a single crystal of Mg. The cantilever beams have dimensions in the order of a few micrometers and a pentagonal cross section. Nanoindenter was used for cantilever beam bending and load-displacement curve was received. Cantilevers with two different crystallographic orientations were chosen for the experiment. Three dimensional numerical FE model with elastoplastic behavior respecting crystal anisotropy was used to fit experimental load displacement curves. Strengths and deformation energy were evaluated from the models for each cantilever.

Explicit Finite Element Analyses of Drop Tests With Thin-Walled Steel Sheet Containers for the Konrad Repository

2015 ◽  
Author(s):  
Christian Protz ◽  
Uwe Zencker ◽  
Robert Liebich
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Damage Mechanics ◽  
Steel Sheet ◽  
Assessment Procedure ◽  
Fe Model ◽  
Explicit Finite Element ◽  
Safety Margins ◽  
Drop Tests ◽  
Thin Walled

Alternatively to experimental drop tests, the mechanical safety analyses of containers for final disposal of radioactive waste with negligible heat generation in the German Konrad repository may be carried out by numerical simulations within the safety assessment procedure. In the past, safety assessments for thin-walled steel sheet containers have been done exclusively by prototype tests and unfavorable drop scenarios were determined by engineering judgment. So far, reliable numerical simulations do not exist. Therefore, a research project was started to develop numerical simulation approaches for drop test analyses and to determine existing safety margins. Comparisons of experimental and numerical results confirm that the Finite Element (FE) model represents the general mechanical behavior of the steel sheet container sufficiently. Simulations have been used to determine an unfavorable drop scenario resulting in large deformation and damage. This paper presents the investigations carried out as well as the further development of the FE model in terms of damage mechanics.

Computationally Efficient, Explicit Finite Element Model for Evaluation of Patellofemoral Mechanics

2007 ◽  
Author(s):  
Mark A. Baldwin ◽  
Paul J. Rullkoetter
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Probabilistic Approach ◽  
Element Model ◽  
Relevant Information ◽  
Composite Fiber ◽  
Computational Time ◽  
Patient Specific ◽  
Fe Model ◽  
Explicit Finite Element

Patient-specific finite element (FE) models can provide clinically relevant information about contact mechanics and kinematics that may be difficult or infeasible to obtain otherwise, and have potential to guide pre-operative planning. However, substantial uncertainty in model variables exists in patient-specific modeling, and suggests a probabilistic approach. Although efficient probabilistic methodology has been recently developed, multiple analyses are still required, and computational time for a fully deformable FE model throughout a flexion cycle has typically made this impractical. Therefore, the goal of the present study was to develop an explicit FE model of the patellofemoral joint with deformable cartilage and deformable, wrapping extensor tendons, and to compare kinematic and contact mechanics results with a model modified for computational efficiency. The efficient model incorporated rigid femoral and patellar cartilage representation with an optimized contact pressure–surface overclosure relationship, and composite-fiber tendons.

scholarly journals Explicit Simulation of Circular CFST Stub Columns with External Steel Confinement under Axial Compression

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 23 ◽  
Author(s):  
Faesal Alatshan ◽  
Siti Aminah Osman ◽  
Fidelis Mashiri ◽  
Roszilah Hamid
Keyword(s):  
Failure Modes ◽  
Axial Loading ◽  
Steel Tube ◽  
Fe Model ◽  
Explicit Finite Element ◽  
Steel Ratio ◽  
Short Columns ◽  
Early Loading ◽  
Experimental Findings ◽  
The Impact

Concrete-filled steel tube (CFST) structural members have been widely used in engineering projects for their superior strength and ductility. However, the different lateral dilation characteristics between concrete infill and steel tube have caused imperfect composite interaction during the early loading stage. To overcome this issue, external steel confinements in the form of rings and spiral were previously suggested to minimise the lateral expansion of the steel tube and enhance the concrete confinement effects. This study presented the analytical behaviour of circular CFST short columns with an external ring or spiral confinements which are subjected to axial loading. An explicit finite element (FE) model was developed and verified based on previous experimental findings. Besides that, this study analysed the failure modes, axial load–strain relationship, stress distributions, and bond strength of the composite column components. Parametric analysis was also undertaken to evaluate the impact of material strengths, total steel ratio, and diameter-to-thickness ratio. The results suggest that the use of external steel confinement can enhance the compressive behaviour of CFSTs better than increasing the thickness of the steel tube when using the same steel ratio. Finally, simplified design formulations were developed to accurately calculate the ultimate capacity of CFST columns with and without external steel confinement.

Simulation of Discreet Damage Evolution in Laminated Composite Compact Tension Specimens

2012 ◽  
Author(s):  
T. D. Breitzman ◽  
D. H. Mollenhauer ◽  
E. V. Iarve ◽  
S. Safriet
Keyword(s):  
Damage Mechanics ◽  
Peak Load ◽  
Compact Tension ◽  
Matrix Cracking ◽  
Displacement Curve ◽  
Fiber Fracture ◽  
Modeling Framework ◽  
Damage Extent ◽  
Load Displacement ◽  
Matrix Damage

Damage progression in laminated Overheight Compact Tension specimens was modeled using discrete representations of individual cracks and delaminations. Matrix cracking and delamination initiation, propagation, and interaction, without any prior knowledge and/or meshing of matrix cracking surfaces, is accomplished by combining stress and fracture mechanics-based constitutive modeling within a mesh independent crack-modeling framework. Simulation results including only matrix damage for specimens with [452/902/−452/02]s and [04/904]2s stacking sequences were compared with load-displacement curves and 3D X-ray micro computed tomography results from tested specimens. Excellent correlation was shown between the simulated and experimental load-displacement curves including statistical variations and proper representation of both the curve non-linearity and peak load. Similarly, remarkable correlation between simulated and experimental damage extent was shown. Additionally, a [45/90/−45/0]2s specimen exhibiting significant fiber fracture was modeled and results compared with experiment. Fiber fracture was simulated using a continuum damage mechanics approach in addition to the discrete cracking and delamination damage representations of matrix damage. The simulated load displacement curve and damage extent compared favorably with experimental results.

scholarly journals THE CRASH ENERGY ABSORPTION OF THE VEHICLES FRONT STRUCTURES

Transport ◽  
2003 ◽  
Vol 18 (2) ◽  
pp. 97-101 ◽  
Author(s):  
Paulius Griškevičius ◽  
Antanas Žiliukas
Keyword(s):  
Mechanical Characteristics ◽  
Axial Loading ◽  
Computer Code ◽  
Experimental Investigations ◽  
Fe Model ◽  
Structural Elements ◽  
Crash Analysis ◽  
Absorbed Energy ◽  
Frontal Crash ◽  
Energy Absorbing

During the frontal crash the longerons absorb most energy of all vehicles construction elements. In order to analyse the energy absorbing capabilities of longerons under axial compression loading and to evaluate the influence of longerons geometrical characteristics and materials degradation on the vehicles safety experimental investigations and numerical calculations were performed. To assess the crashworthiness of longerons the main objective was to study the behaviour of thin-walled structural elements under axial loading conditions using the Finite Element (FE) model. The numerical FE models were created using the computer code LS-DYNA. Two models of longerons were investigated with different sections shape and for each of them materials with the four different mechanical characteristics were applied. Validation of created FE model was performed according to the experimental investigation and the results were obtained of validated FE models of vehicles crash analysis [1]. The results of analyses show that the value of absorbed energy by the longerons of new vehides exceeds the value of the oldest cars. The degradation of structures in the old cars has the significant influence on the absorbed energy.

scholarly journals Simulation Research on the Load Transfer Mechanism of Anchoring System in Soft and Hard Composite Rock Strata under Tensile Loading Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Ning Li ◽  
Zhanguo Ma ◽  
Peng Gong ◽  
Fuzhou Qi ◽  
Tuo Wang ◽  
...  
Keyword(s):  
Load Transfer ◽  
Hard Rock ◽  
Peak Load ◽  
Thickness Ratio ◽  
Displacement Curve ◽  
Initial Stiffness ◽  
Bond Slip ◽  
Anchoring System ◽  
Load Displacement ◽  
Rock Strata

Soft and hard composite rock strata are frequently encountered in transportation, geotechnical, and underground engineering. However, most of the current support is designed for homogeneous rock masses, which ignores the different anchoring effect in soft and hard composite rock strata. A numerical study is presented in this paper on the pull-out behavior of fully grouted rock bolts in soft and hard composite rock strata. The nonlinear bond-slip relationship of bolt-grout interface that is anchored in soft rock and hard rock is obtained from laboratory test, respectively. Then, the nonlinear bond-slip relationship is put into the numerical model. The numerical result shows a close match with the experiment tests and the proposed model. Lithological sequence, layer thickness ratio, and layer numbers are taken into consideration in numerical simulation models. Under the same layer number, the shallower-soft and deeper-hard composite rock strata (SHCRS) have a higher bearing capacity and deformation resistance than the shallower-hard and deeper-soft composite rock strata (HSCRS). As the soft-to-hard thickness ratio in SHCRS increases, the initial stiffness of the load-displacement curve and peak load decreases continuously. The load-displacement curve shows the same initial stiffness for different hard to soft thickness ratios in HSCRS. As the hard to soft thickness ratio increases, the load peak and the displacement at the peak load increase. Therefore, the closer the hard rock is to the loading end, the greater the initial stiffness of the load-displacement curve is. The greater the hard rock thickness, the larger the peak load. Under the same anchor length, the peak load and the displacement at the peak load decrease with the increase of layer numbers, but the reduction magnitude decreases. This paper leads to a better understanding of the load transfer mechanism for the anchoring system in soft and hard composite strata and provides a reference for scientific support design and evaluation method.

Parametrical Investigations on Concrete-Jacketed RC Columns with Pre- and Post-Corrosion Damage

2015 ◽  
Vol 1101 ◽  
pp. 368-372
Author(s):  
Sai Sai Wang
Keyword(s):  
Reinforced Concrete ◽  
Axial Compression ◽  
Peak Load ◽  
Axial Loading ◽  
Corrosion Damage ◽  
Rc Columns ◽  
Distinct Effect ◽  
Rc Column ◽  
Parametric Studies ◽  
Rebar Corrosion

The main objective of this study is to parametrically investigate the effect of pre-and post-corrosion and loading damage on concrete-jacketed reinforced concrete (RC) columns under uni-axial loading. A model capable of evaluating the squash load of un-jacketed or jacketed RC columns with and without corrosion damage was induced. The parametric studies based on this model are meant to investigate the effect of rebar corrosion on the axial compression capacity of jacketed RC column. It was concluded that the longitudinal rebar corrosion has more distinct effect on the peak load than that of web rebar. The jacketing rebar corrosion has more distinct effect on the peak load than that of substrate rebar.

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