Investigation on Steel Staggered-Truss System RC Slab

2012 ◽  
Vol 446-449 ◽  
pp. 49-53
Author(s):  
Qing Sheng Guo ◽  
Qing Shan Yang
Keyword(s):  
Response Spectrum ◽  
High Stress ◽  
Shell Element ◽  
3D Models ◽  
Structure Design ◽  
Vertical Load ◽  
Element Analysis ◽  
Design Defect ◽  
Rc Slab ◽  
Rc Slabs

For steel staggered-truss (SST) system, RC slabs are the main structure members to make the whole building work together beside to take the vertical load. There are openings in the RC slabs due to requirement of staircases、lift wells and other services, these openings will reduce the stiffness of RC slab and make stress concentration. Usually, the RC slab is designed under vertical load only, this will lead to the design defect and building calapse for SST structure. There are few research for SST RC slab are presented untill now. In the paper, based on two different 3D models considering or ignoring the stiffness of infilled walls (SIW), a numerical investigation is presented on the structural behaviors of the SST system utilizing the soft ware ETABS. As a finite element analysis method, the shell element is adopted for RC slab & infilled wall, the beam element is adopted for beam、colum and truss members. The structure is asymmetrical due to the SIW, it causes the torsional forces in the building and the extra stresses in the RC slabs, the additional reinforcement need to be provided to strengthen the high stress areas. Comparing with the results of response spectrum analysis under the combination with earth quake load, we make some conclusions, including the capacity of anti-seismic and the effect of the SIW for SST system RC slab，that could be a reference for SST structure design.

Investigation on the Effect of Infilled Walls Utilizing Response Spectrum Analysis for Steel Staggered-Truss System

2012 ◽  
Vol 152-154 ◽  
pp. 34-39
Author(s):  
Qing Sheng Guo ◽  
Qing Shan Yang
Keyword(s):  
Spectrum Analysis ◽  
Earth Quake ◽  
Simulation Analysis ◽  
Response Spectrum ◽  
Steel Structure ◽  
3D Models ◽  
Structure Design ◽  
Seismic Load ◽  
Base Shear ◽  
Response Spectrum Analysis

Considering the structure type of the steel staggered-truss (SST) system, the effect of infilled walls will be major and need to be studied amply, some scientific design regulations need to be found for referrence. Based on two different 3D models considering or ignoring the stiffness of infilled walls (SIW), a numerical investigation is presented on the structural behaviors of the SST system utilizing the finite element 3D simulation analysis soft ware ETABS. The longitudinal structure is asymmetrical due to the SIW, it causes the torsion forces in the building. Comparing to the different results of response spectrum analysis, including storey drift and equivalent base shear under frequent earth quake and rare earth quake, some conclusions were made, including the capacity of the SST system under seismic load and the effect of the SIW for SST system. The increased base shear force factors due to the effect of the SIW were suggested for SST structure design, it is different from the other steel structure types.

scholarly journals Damage mechanism of existing RC slabs with reinforcing steel plate

2019 ◽  
Vol 258 ◽  
pp. 05011
Author(s):  
Kenta Namba ◽  
Chikako Fujiyama ◽  
Tsutomu Niina
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Simulation Models ◽  
Damage Mechanism ◽  
Steel Plates ◽  
Reinforcing Steel ◽  
Wheel Load ◽  
Element Analysis ◽  
Rc Slab ◽  
Rc Slabs

The purpose of this study was to clarify the damage mechanisms of existing reinforced concrete (RC) slabs with reinforcing steel plates through the use of a three-dimensional nonlinear finite element analysis. An actual wheel load running test was simulated. Two panels of RC slab were cut from existing bridges and were used as the test specimens. Simulation models were built for each specimen with different modeling concepts for the rebar; RC elements, and solid elements. After the wheel load running simulations, the strains were examined through use of the strain contours at various cross sections. In the model using solid element for the rebars, the mechanisms for the generation and development of the horizontal cracks were analyzed in detail. Furthermore, the strain components of the referential elements were carefully analyzed for different loading cycles and positions. Although the decisive cause of the horizontal crack has not been clarified yet, the crack development processes were mostly demonstrated through this study.

The Dynamics in Implantation for Patients with Clefts

2006 ◽  
Vol 43 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Tomohisa Nagasao ◽  
Junpei Miyamoto ◽  
Hongmei Jin ◽  
Tamotsu Tamaki ◽  
Yasushige Isshiki ◽  
...  
Keyword(s):  
Finite Element ◽  
Quantitative Difference ◽  
Three Dimensional ◽  
Element Model ◽  
3D Models ◽  
Horizontal Load ◽  
Vertical Load ◽  
Element Analysis ◽  
Stress Patterns ◽  
Implant Treatment

Objective To investigate the stresses and strains of an endosseous dental implant in patients with different types of cleft palate in a finite element model. Materials and Methods Seven three-dimensional (3D) maxillary models were designed on a personal computer according to computed tomography slice data obtained from seven dry skulls. Next, computer-aided modification was performed on each model to produce three other 3D models with different cleft patterns. Thus, four model types with different cleft patterns were designed and termed NORM (without cleft), ALVEOLAR (only alveolar cleft), PALATAL (only palatal cleft), and COMPLETE (complete cleft). An implant was embedded into the molar region of each model, and a 300-N vertical load and 50-N horizontal load were applied to simulate mastication. Under these conditions, the stresses occurring at the implant-bone interface were calculated by finite element analysis. Results Different stress patterns were observed between the models with a palatal cleft (PALATAL and COMPLETE) and those without palatal cleft (NORM and ALVEOLAR). Regarding vertical load application, greater stresses occurred in PALATAL and COMPLETE types than in NORM and ALVEOLAR types. On application of a horizontal load, though the stresses did not show quantitative difference, their vector patterns differed. Conclusion In patients with palatal clefts, characteristic stress patterns occur on the bone-implant interface during mastication. This should be taken into consideration when performing an implant treatment in patients with clefts.

Vibration Behavior of Composite Slab with Precast Ribbed Panels due to Transient Impact

2019 ◽  
Vol 19 (12) ◽  
pp. 1950148
Author(s):  
Jiepeng Liu ◽  
Shu Huang ◽  
Jiang Li ◽  
Y. Frank Chen
Keyword(s):  
Finite Element ◽  
Field Tests ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Composite Slab ◽  
Vibration Behavior ◽  
Floor Vibrations ◽  
Rc Slab ◽  
Rc Slabs ◽  
Floor System

Excessive floor vibrations due to human activities such as heel-drop and jumping can induce annoyance to occupants and cause a serious serviceability problem. Both field tests and finite element analysis were conducted to study the vibration behavior of the composite slab with precast ribbed panels (CSPRP), a relatively new floor system compared with the cast-in-place reinforced concrete (RC) slab. In addition, both heel-drop and jumping impacts were employed to generate the acceleration response of the floor, from which two important vibration characteristics of natural frequencies and damping ratios are obtained. A comparison of the vibration behavior of CSPRPs with RC slabs indicates that the former exhibits more satisfactory perceptibility in terms of vibration. Appropriate coefficients (i.e. [Formula: see text] and [Formula: see text]) with the root-mean-square and peak accelerations subjected to heel-drop and jumping excitations are proposed for both CSPRPs and RC slabs. Lastly, an extensive parametric study considering different boundary conditions, floor types, and floor spans was carried out using the finite element method. It is recommended to use CSPRP under 3.3[Formula: see text]m span in order to keep the fundamental frequency above 3.0[Formula: see text]Hz.

scholarly journals Three-Dimensional Finite Element Analysis of Varying Diameter and Connection Type in Implants with High Crown-Implant Ratio

2018 ◽  
Vol 29 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Sandra Lúcia Dantas de Moraes ◽  
Fellippo Ramos Verri ◽  
Joel Ferreira Santiago Júnior ◽  
Daniel Augusto de Faria Almeida ◽  
Cleidiel Aparecido Araujo Lemos ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Cortical Bone ◽  
High Stress ◽  
Axial Loading ◽  
3D Models ◽  
Element Analysis ◽  
Wide Diameter ◽  
Oblique Loading ◽  
Connection Type

Abstract The aim of this study was to evaluate the effect of varying the diameter, connection type and loading on stress distribution in the cortical bone for implants with a high crown-implant ratio. Six 3D models were simulated with the InVesalius, Rhinoceros 3D 4.0 and SolidWorks 2011 software programs. Models were composed of bone from the posterior mandibular region; they included an implant of 8.5 mm length, diameter Ø 3.75 mm or Ø 5.00 mm and connection types such as external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Models were processed using the Femap 11.2 and NeiNastran 11.0 programs and by using an axial force of 200 N and oblique force of 100 N. Results were recorded in terms of the maximum principal stress. Oblique loading showed high stress in the cortical bone compared to that shown by axial loading. The results showed that implants with a wide diameter showed more favorable stress distribution in the cortical bone region than regular diameter, regardless of the connection type. Morse taper implants showed better stress distribution compared to other connection types, especially in the oblique loading. Thus, oblique loading showed higher stress concentration in cortical bone tissue when compared with axial loading. Wide diameter implant was favorable for improved stress distribution in the cortical bone region, while Morse taper implants showed lower stress concentration than other connections.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

scholarly journals Behavior of Offshore Pile in Calcareous Sand—Case Study

2021 ◽  
Vol 9 (8) ◽  
pp. 839
Author(s):  
Tarek N. Salem ◽  
Nadia M. Elkhawas ◽  
Ahmed M. Elnady
Keyword(s):  
Load Capacity ◽  
High Stress ◽  
Embedment Depth ◽  
Shear Stresses ◽  
Northern Coast ◽  
Compression Tests ◽  
Calcareous Sand ◽  
Element Analysis ◽  
Mixing Ratios

The erosion of limestone and calcarenite ridges that existed parallel to the Mediterranean shoreline forms the calcareous sand (CS) formation at the surface layer of Egypt's northern coast. The CS is often combined with broken shells which are considered geotechnically problematic due to their possible crushability and relatively high compressibility. In this research, CS samples collected from a site along the northern coast of Egypt are studied to better understand its behavior under normal and shear stresses. Reconstituted CS specimens with different ratios of broken shells (BS) are also investigated to study the effect of BS ratios on the soil mixture strength behavior. The strength is evaluated using laboratory direct-shear and one-dimensional compression tests (oedometer test). The CS specimens are not exposed to significant crushability even under relatively high-stress levels. In addition, a 3D finite element analysis (FEA) is presented in this paper to study the degradation offshore pile capacity in CS having different percentages of BS. The stress–strain results using oedometer tests are compared with a numerical model, and it gave identical matching for most cases. The effects of pile diameter and embedment depth parameters are then studied for the case study on the northern coast. Three different mixing ratios of CS and BS have been used, CS + 10% BS, CS + 30% BS, and CS + 50% BS, which resulted in a decrease of the ultimate vertical compression pile load capacity by 8.8%, 15%, and 16%, respectively.

scholarly journals Mechanical Integrity Assessment of Two-Side Etched Type Printed Circuit Heat Exchanger with Additional Elliptical Channel

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4711
Author(s):  
Armanto P. Simanjuntak ◽  
Jae-Young Lee
Keyword(s):  
Heat Exchanger ◽  
Stress Intensity ◽  
Maximum Stress ◽  
High Stress ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Printed Circuit ◽  
Mechanical Integrity ◽  
Finite Element Analysis Simulation ◽  
Maximum Stress Intensity

Printed circuit heat exchangers (PCHEs) are often subject to high pressure and temperature difference between the hot and cold channels which may cause a mechanical integrity problem. A conventional plate heat exchanger where the channel geometries are semi-circular and etched at one side of the stacked plate is a common design in the market. However, the sharp edge tip channel may cause high stress intensity. Double-faced type PCHE appears with the promising ability to reduce the stress intensity and stress concentration factor. Finite element analysis simulation has been conducted to observe the mechanical integrity of double-etched printed circuit heat exchanger design. The application of an additional ellipse upper channel helps the stress intensity decrease in the proposed PCHE channel. Five different cases were simulated in this study. The simulation shows that the stress intensity was reduced up to 24% with the increase in additional elliptical channel radius. Besides that, the horizontal offset channels configuration was also investigated in this study. Simulation results show that the maximum stress intensity of 2.5 mm offset configuration is 9% lower compared to the maximum stress intensity of 0 mm offset. This work proposed an additional elliptical upper channel with a 2.5 mm offset configuration as an optimum design.

Novel Trapezoidal-Loop Piezoelectric Energy Harvester

2014 ◽  
Vol 672-674 ◽  
pp. 402-406
Author(s):  
Bing Jiang ◽  
Shuai Yuan ◽  
Xiao Hui Xu ◽  
Mao Sheng Ding ◽  
Ye Yuan ◽  
...  
Keyword(s):  
Output Voltage ◽  
Energy Harvester ◽  
Research Field ◽  
Structure Design ◽  
Loop Structure ◽  
Element Analysis ◽  
Resonant Frequencies ◽  
First Order ◽  
Microelectronic Devices ◽  
Piezoelectric Energy

In recent years, piezoelectric energy harvester which can replace the traditional battery supply has become a hot topic in global research field of microelectronic devices. Characteristics of a trapezoidal-loop piezoelectric energy harvester (TLPEH) were analyzed through finite-element analysis. The output voltage density is 4.251V/cm2 when 0.1N force is applied to the free end of ten-arm energy harvester. Comparisons of the resonant frequencies and output voltages were made. The first order resonant frequency could reach 15Hz by increasing the number of arms. Meanwhile, the output voltage is improved greatly when excited at first-order resonant frequencies. The trapezoidal-loop structure of TLPEH could enhance frequency response, which means scavenging energy more efficiently in vibration environment. The TLPEH mentioned here might be useful for the future structure design of piezoelectric energy harvester with low resonance frequency.

Design of Oil Injection Quills for Hypercompressors Cylinders

2011 ◽  
Author(s):  
Guido Volterrani ◽  
Carmelo Maggi ◽  
Marco Manetti
Keyword(s):  
Finite Element Analysis ◽  
Fracture Mechanics ◽  
Residual Stresses ◽  
High Stress ◽  
Element Analysis ◽  
Threaded Connection ◽  
Advanced Technologies ◽  
Inner Diameter ◽  
Oil Injection ◽  
Autofrettage Pressure

Fatigue impacts the life of all components subject to alternating loads, including lube oil injection quills. These occurrences are more frequent if a defect (initial flaw) nucleates in the component due to corrosion, high stress, machining imperfections, etc. The design of components undergoing high fluctuating pressures needs advanced technologies, like autofrettage, and design methods, like FEM or fracture mechanics. This component can be identified as a cylinder with different outside diameters and notches deriving from the geometry variation and threaded connection. The inner diameter is the most stressed area and will require an adequate stress analysis. A sensitivity analysis of the autofrettage pressure can be performed to identify the most appropriate residual stresses on the inner diameter and to obtain a threshold defect larger than the minimum detectable. Fracture mechanics allows the analysis the propagation of an initial defect with materials having different properties and considering different autofrettage pressures. Finite Element Analysis is used to validate the residual stresses predicted by calculation for each autofrettage pressure. An optimized solution of the hypercompressor injection quill can be designed.

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