A Simplified Method for Estimating the Amount of Energy Dissipated by Flexure-Dominated Reinforced Concrete Members for Moderate Cyclic Deformations

2006 ◽  
Vol 22 (2) ◽  
pp. 459-490 ◽  
Author(s):  
Honggun Park ◽  
Taesung Eom
Keyword(s):  
Reinforced Concrete ◽  
Compressive Force ◽  
Cyclic Behavior ◽  
Dissipated Energy ◽  
Structural Walls ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Concrete Members ◽  
Simplified Method ◽  
Energy Dissipated

In advanced earthquake analysis/design methods, the cyclic behavior of reinforced concrete (RC) members, which is characterized by strength, deformability, and the amount of dissipated energy, must be estimated with reasonable precision. However, presently, the amount of dissipated energy is estimated by either empirical equations, which are not sufficiently accurate, or experiments and sophisticated numerical analysis, which are difficult to use in practice. In the present study, nonlinear finite element analysis was performed to investigate the behavioral characteristics of flexure-dominated RC members subject to moderate plastic displacements. The results showed that flexural pinching can occur due to the effects of axial compressive force and asymmetrical rebar arrangement. However, axial force has little effect on the energy dissipation. The arrangement and ratio of reinforcement have substantial effects. Based on the findings, a simplified method to estimate the energy dissipated by flexure-dominated members was developed, and was verified by comparing its results with those of existing experiments on beams, columns, and structural walls.

Biomechanical Study of Lumbar Spine (L2-L4) Using Hybrid Stabilization Device - A Finite Element Analysis

2020 ◽  
Vol 10 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Pushpdant Jain ◽  
Mohammed Rajik Khan
Keyword(s):  
Finite Element ◽  
Compressive Force ◽  
Element Model ◽  
Biomechanical Study ◽  
Bottom Surface ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Hybrid Stabilization ◽  
Flexion Extension ◽  
Lumbar Segment

Spinal instrumentations have been designed to alleviate lower back pain and stabilize the spinal segments. The present work aims to evaluate the biomechanical effect of the proposed Hybrid Stabilization Device (HSD). Non-linear finite element model of lumbar segment L2-L4 were developed to compare the intact spine (IS) with rigid implant (RI) and hybrid stabilization device. To restrict all directional motion vertebra L4 bottom surface were kept fixed and axial compressive force of 500N with a moment of 10Nm were applied to the top surface of L2 vertebrae. The results of range of motion (ROM), intervertebral disc (IVD) pressure and strains for IVD-23 and IVD-34 were determined for flexion, extension, lateral bending and axial twist. Results demonstrated that ROM of HSD model is higher than RI and lower as compared to IS model. The predicted biomechanical parameters of the present work may be considered before clinical implementations of any implants.

scholarly journals Buckling Knockdown Factors of Composite Cylinders under Both Compression and Internal Pressure

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 346
Author(s):  
Do-Young Kim ◽  
Chang-Hoon Sim ◽  
Jae-Sang Park ◽  
Joon-Tae Yoo ◽  
Young-Ha Yoon ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Axial Compression ◽  
Shell Thickness ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Thickness Ratio ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Thin Walled ◽  
Composite Cylinders

The internal pressure of a thin-walled cylindrical structure under axial compression may improve the buckling stability by relieving loads and reducing initial imperfections. In this study, the effect of internal pressure on the buckling knockdown factor is investigated for axially compressed thin-walled composite cylinders with different shell thickness ratios and slenderness ratios. Various shell thickness ratios and slenderness ratios are considered when the buckling knockdown factor is derived for the thin-walled composite cylinders under both axial compression and internal pressure. Nonlinear post-buckling analyses are conducted using the nonlinear finite element analysis program, ABAQUS. The single perturbation load approach is used to represent the geometric initial imperfection of thin-walled composite cylinders. For cases with the axial compressive force only, the buckling knockdown factor decreases as the shell thickness ratio increases or as the slenderness ratio increases. When the internal pressure is considered simultaneously with the axial compressive force, the buckling knockdown factor decreases as the slenderness ratio increases but increases as the shell thickness ratio increases. The buckling knockdown factors considering the internal pressure and axial compressions are higher by 2.67% to 38.98% compared with the knockdown factors considering the axial compressive force only. The results show the significant effect of the internal pressure, particularly for thinner composite cylinders, and that the buckling knockdown factors may be enhanced for all the shell thickness ratios and slenderness ratios considered in this study when the internal pressure is applied to the cylinder.

Sustainable Reinforced Concrete Design of Structural Walls

2021 ◽  
Vol 891 ◽  
pp. 218-222
Author(s):  
Styliani Papatzani ◽  
Ioannis Giannakis ◽  
Sotirios A. Grammatikos ◽  
Michael D. Kotsovos ◽  
Subrata Chandra Das
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Natural Resources ◽  
Compressive Force ◽  
Transverse Reinforcement ◽  
Structural Walls ◽  
Structural Wall ◽  
Target Values

Sustainability calls for reduction in the use of natural resources and man-made materials. In light of this, the present study demonstrates the potentials of the reduction of transverse reinforcement in structural walls. A structural wall 1.7 m long was designed following the Greek Code for Reinforced Concrete (GCRC). This wall was then constructed and tested under cyclic loading. The theoretical value of the uncracked stiffness was four times greater than the value calculated after the experiment. The wall was also designed according to the Compressive Force Path method (CFP), which allowed for a significant reduction in the transverse reinforcement for the same target values.

Reduced-thickness CVN testing to represent slant failure of pipelines

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Jeroen Van Wittenberghe ◽  
Philippe Thibaux ◽  
Patrick Goes
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Propagation Speed ◽  
High Strength ◽  
Dissipated Energy ◽  
Specimen Thickness ◽  
Absorbed Energy ◽  
Element Analysis ◽  
The Difference ◽  
Energy Dissipated

To avoid longitudinal ductile crack propagation along a gas pipeline, the Batelle Two Curve method is used during pipeline design. This method states that a running crack will be arrested if the gas decompression velocity exceeds the crack propagation speed at the internal gas pressure. The crack propagation curve is scaled by impact energy values obtained through Charpy V-Notch (CVN) testing. However, for high-strength steel grades this scaling leads to unconservative predictions, because the experiment does not sufficiently represent the pipeline failure mode. The CVN specimen exhibits mainly mode I failure, without significant shear lips, while real failure is a combined mode often described as slant failure. In the present study, instrumented CVN tests are carried out on samples with different thickness reduction levels. To get a better insight in the crack initiation and propagation behaviour, the CVN test is simulated by finite element analysis. The dissipated energy and resulting fracture surfaces can be successfully represented. It is observed that slant failure is promoted by reducing the specimen thickness. In addition, the specific absorbed energy is decreased. However, most of the difference of absorbed energy is in crack initiation. This means that the fraction of the total energy dissipated in crack propagation is increased for reduced thickness specimens, making it a possible tool to assess the resistance of a material to crack propagation, provided that brittle fracture is avoided.

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