Punching Shear Design Method of Voided Slabs

2017 ◽  
Vol 754 ◽  
pp. 333-336
Author(s):  
Joo Hong Chung ◽  
Hyun Ki Choi ◽  
Chang Sik Choi ◽  
Hyung Suk Jung
Keyword(s):  
Finite Element Analysis ◽  
Shear Strength ◽  
Design Method ◽  
Fe Analysis ◽  
Punching Shear ◽  
Test Results ◽  
Sectional Area ◽  
Element Analysis ◽  
Cross Sectional ◽  
Shear Design

This study presents punching shear design method of voided slab in accordance with arrangement of voids around columns. According to previous studies, the slab-column connection of voided slabs is weaker than that of the solid slab due to the lack of cross-sectional area of concrete by voids. In this study, it is assumed that the arrangement of voids exert influence on the punching shear strength of voided slabs. To verify the assumption, finite element analysis was conducted related with previous test results. The variable of FE analysis was a distance between voids and column face. Based on FE analysis and test results including previous studies, punching shear design method is suggested which can consider the arrangement of voids around columns. The suggested design method is based on the punching shear design method in ACI-318. As a result, it can predict the punching shear strength of voided slabs according to arrangement of voids around column.

Shear Strength of the Perfobond Connection of a Steel-Concrete Composite Slim Floor System

2015 ◽  
Vol 764-765 ◽  
pp. 1134-1138
Author(s):  
Hong C. Rhim ◽  
Kwang Ho Lee ◽  
Won Seok Jang ◽  
Seong Hoon Jeong ◽  
Dae Jin Kim ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Shear Strength ◽  
Structural Behavior ◽  
Test Results ◽  
Analysis Model ◽  
Element Analysis ◽  
Cross Sectional ◽  
Finite Element Analysis Model ◽  
Floor System ◽  
Push Out

The use of steel-concrete composite members has been significantly increased as they have the advantages of the reduction of cross sectional areas, excellent ductility against earthquake loadings and a longer life span than typical steel frame members. In this paper, push-out tests were performed on six specimens to investigate the structural behavior and shear strength of perfobond connection of a steel-concrete composite slim floor system. An equation to theoretically estimate the shear strength of the perfobond connection is proposed, and its accuracy is examined by comparing its predictions with the test results. A finite element analysis model is also developed and used to confirm the effectiveness of the proposed strength equation.

scholarly journals Shear Performance of Optimized-Section Precast Slab with Tapered Cross Section

2018 ◽  
Vol 11 (1) ◽  
pp. 163 ◽  
Author(s):  
Hyunjin Ju ◽  
Sun-Jin Han ◽  
Hyo-Eun Joo ◽  
Hae-Chang Cho ◽  
Kang Kim ◽  
...  
Keyword(s):  
Cross Section ◽  
Design Method ◽  
Precast Concrete ◽  
Bending Moment ◽  
Shear Behaviour ◽  
Element Analysis ◽  
Cross Sectional ◽  
Shear Design ◽  
Shear Performance ◽  
And Performance

The optimized-section precast slab (OPS) is a half precast concrete (PC) slab that highlights structural aesthetics while reducing the quantity of materials by means of an efficient cross-sectional configuration considering the distribution of a bending moment. However, since a tapered cross section where the locations of the top and bottom flanges change is formed at the end of the member, stress concentration occurs near the tapered cross section because of the shear force and thus the surrounding region of the tapered cross section may become unintentionally vulnerable. Therefore, in this study, experimental and numerical research was carried out to examine the shear behaviour characteristics and performance of the OPS with a tapered cross section. Shear tests were conducted on a total of eight OPS specimens, with the inclination angle of the tapered cross section, the presence of topping concrete and the amount of shear reinforcement as the main test variables and a reasonable shear-design method for the OPS members was proposed by means of a detailed analysis based on design code and finite-element analysis.

Design Innovation Size and Shape Optimization of a 1.0mm Multifunctional Forceps-Scissors Surgical Instrument

2008 ◽  
Vol 2 (1) ◽  
Author(s):  
Milton E. Aguirre ◽  
Mary Frecker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shape Optimization ◽  
Optimization Problems ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Element Analysis ◽  
Cross Sectional ◽  
Size And Shape ◽  
The Cross

A size and shape optimization routine is developed for a 1.0mm diameter multifunctional instrument for minimally invasive surgery. The instrument is a compliant mechanism capable of both grasping and cutting. Multifunctional instruments are expected to be beneficial in the operating room because of their ability to perform multiple surgical tasks, thereby decreasing the total number of instrument exchanges in a single procedure. With fewer instrument exchanges, the risk of inadvertent tissue trauma as well as overall surgical time and costs are reduced. The focus of this paper is to investigate the performance effects of allowing the cross-sectional area along the length of the device to vary. This investigation is accomplished by defining various cross-sectional segments in terms of parametric variables and optimizing the dimensions of the instrument to provide a sufficient opening of the forceps jaws while maintaining adequate cutting and grasping forces. Two optimization problems are considered. First, all parametric segments are set equal to one another to achieve size optimization. Second, each segment is allowed to vary independently, thereby achieving shape optimization. Large deformation finite element analysis and optimization are conducted using ANSYS®. Finally, prototypes are fabricated using wire EMD and experiments are conducted to evaluate the instrument performance. As a result of allowing the cross-sectional area to vary, i.e., conducting shape optimization, the forceps and scissors blocked forces increased by as much as 83.2% and 87%, respectively. During prototype evaluations, it is found that the finite element analysis predictions were within 10% of the measured tool performance. Therefore, for this application, it is concluded that performing shape optimization does significantly influence the performance of the instrument.

scholarly journals A Novel Approach to Design Lesion-Specific Stents for Minimum Recoil

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Farhan Khan ◽  
David Brackett ◽  
Ian Ashcroft ◽  
Christopher Tuck ◽  
Ricky Wildman
Keyword(s):  
Finite Element Analysis ◽  
Topology Optimization ◽  
Material Properties ◽  
Sectional Area ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design Concepts ◽  
Novel Approach ◽  
Stenosed Artery ◽  
Stenotic Arteries

Stent geometries are obtained by topology optimization for minimized compliance under different stenosis levels and plaque material types. Three levels of stenosis by cross-sectional area, i.e., 30%, 40%, and 50% and three different plaque material properties, i.e., calcified, cellular, and hypocellular, were studied. The raw optimization results were converted to clear design concepts and their performance was evaluated by implanting them in their respective stenosed artery types using finite element analysis. The results were compared with a generic stent in similar arteries, which showed that the new designs showed less recoil. This work provides a concept that stents could be tailored to specific lesions in order to minimize recoil and maintain a patent lumen in stenotic arteries.

scholarly journals Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

2020 ◽  
Author(s):  
Jingchi Li ◽  
Zhipeng Xi ◽  
Xiaoyu Zhang ◽  
Shenglu Sun ◽  
Lin Xie ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Imaging Data ◽  
Element Analysis ◽  
Cross Sectional ◽  
Fea Model ◽  
Nucleus Position

Abstract Background: As a widely used biomechanical research method, finite element analysis (FEA) is an important tool for investigating the pathogenesis of disc degenerative diseases and optimizing spine surgical methods. However, the definitions of the relative nucleus position and its cross-sectional area ratio do not conform to a uniform standard, thus affecting the accuracy (ACC) of the FEA. Hence, this study aimed to determine a precise definition of the relative nucleus position and its cross-sectional area ratio to increase the ACC of the following FEA studies. Methods: The lumbar relative nucleus position and its cross-sectional area ratio were measured from magnetic resonance imaging data and then calibrated and validated via FEA. Imaging data from patients without disc degeneration were used. The L4-L5 nucleus and disc cross-sectional areas and the distances between the edges of the annulus and nucleus were measured; the ratios between these values were calculated as P1 and P2, respectively. The FEA model was constructed using these measured values, and the relative nucleus position was calibrated by estimating the differences in the range of motion (ROM) between the model, wherein the ligaments, facet joints and nucleus were suppressed, and that of an in vitro study. Then, the ACC was re-estimated in the model with all non-bony structures by comparing the ROM, the intradiscal pressure (IDP), the facet contact force (FCF) and the disc compression (DC) under different sizes and directions of moments magnitudes to validate the measured and calibrated indicators. Results: The interobserver homogeneity was acceptable, and the measured P1 and P2 values were 1.22 and 38%, respectively. Furthermore, an ACC of up to 99% was attained for the model under flexion–extension conditions when the calibrated P1 value (1.62) was used, with a model validation of greater than 90% attained under al most all of the loading conditions considering the different indicators and moment magnitude s. Conclusion: The measured and calibrated relative nucleus position and its cross-sectional area ratio increase the ACC of the FEA model and can therefore be used in subsequent studies.

Shear Strength Characteristics of an Ultrasonic Welded Lap Shear Joint

2002 ◽  
Author(s):  
Samuel Ibekwe ◽  
Patrick F. Mensah ◽  
Amitava Jana ◽  
Guoqiang Li ◽  
Michael A. Stubblefield
Keyword(s):  
Finite Element Analysis ◽  
Shear Strength ◽  
Fiber Composite ◽  
Test Results ◽  
Lap Joint ◽  
Element Analysis ◽  
Lap Shear ◽  
Shear Joint ◽  
Glass Fiber Composite ◽  
Fiber Composite Materials

Experimental attempts were carried out on ultrasonically joining glass fiber composite materials using fiber reinforced adhesive. Two sets of specimens with different energy guides were investigated. All the samples failed by shear at the interface of the lap joint. Finite element analysis was conducted to justify the test results and the effect of adherend surface treatment.

Measurement of pharyngeal cross-sectional area by finite element analysis

2006 ◽  
Vol 100 (1) ◽  
pp. 294-303 ◽  
Author(s):  
Khaled F. Mansour ◽  
James A. Rowley ◽  
M. Safwan Badr
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Eye Movement ◽  
Rem Sleep ◽  
Sectional Area ◽  
Element Analysis ◽  
Cross Sectional ◽  
Pharyngeal Pressure ◽  
Simultaneous Measurements ◽  
The Mean

A noninvasive measurement of pharyngeal cross-sectional area (CSA) during sleep would be advantageous for research studies. We hypothesized that CSA could be calculated from the measured pharyngeal pressure and flow by finite element analysis (FEA). The retropalatal airway was visualized by using a fiber-optic scope to obtain the measured CSA (mCSA). Flow was measured with a pneumotachometer, and pharyngeal pressure was measured with a pressure catheter at the palatal rim. FEA was performed as follows: by using a three-dimensional image of the upper airway, a mesh of finite elements was created. Specialized software was used to allow the simultaneous calculation of velocity and area for each element by using the measured pressure and flow. In the development phase, 677 simultaneous measurements of CSA, pressure, and flow from one subject during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep were entered into the software to determine a series of equations, based on the continuity and momentum equations, that could calculate the CSA (cCSA). In the validation phase, the final equations were used to calculate the CSA from 1,767 simultaneous measurements of pressure and flow obtained during wakefulness, NREM, and REM sleep from 14 subjects. In both phases, mCSA and cCSA were compared by Bland-Altman analysis. For development breaths, the mean difference between mCSA and cCSA was 0.0 mm2 (95% CI, −0.1, 0.1 mm2). For NREM validation breaths, the mean difference between mCSA and cCSA was 1.1 mm2 (95% CI 1.3, 1.5 mm2). Pharyngeal CSA can be accurately calculated from measured pharyngeal pressure and flow by FEA.

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