scholarly journals Mechanical Performance of Built-Up Columns Composed of Four Cold-Formed Square Steel Tubes

2019 ◽  
Vol 9 (6) ◽  
pp. 1204 ◽  
Author(s):  
Xiaomiao Chen ◽  
Junwu Xia ◽  
Bo Xu ◽  
Renwei Ma
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Numerical Analysis ◽  
Axial Load ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Numerical Results ◽  
Finite Element Models ◽  
Good Prediction ◽  
Steel Tubes

This study presents an experimental investigation into the mechanical performance of built-up columns composed of four cold-formed square steel tubes under axial load. The four tubes were assembled together with several C-shaped connectors through two self-tapping screws in each junction. The influence of parameters including spacing between tubes, type of connectors and transverse diaphragm were analyzed based on the failure modes, ultimate loads, load-displacement relationships and load-strain relationships measured in the tests. Moreover, a further numerical analysis was carried out to study the effect of the number of connectors, web height of connectors and installing connectors at column ends by means of the verified finite element models. Finally, the numerical results were compared with the strengths predicted by the AISI-S100-2012 code. Results show that the performance of built-up columns can be influenced by the change in the number of connectors and ratio of web height of connectors to spacing between tubes as well as the installation of connectors at column ends. In addition, the current AISI-S100-12 specifications do not provide a good prediction of the built-up columns composed of four cold-formed square steel tubes.

Validation of a Finite Element Model of the Mechanical Performance of Surgical Knots of Varying Topology

2018 ◽  
Author(s):  
Arz Y. Qwam Alden ◽  
Andrew G. Geeslin ◽  
Peter A. Gustafson
Keyword(s):  
Finite Element ◽  
Laboratory Tests ◽  
Computational Models ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Failure Process ◽  
Finite Element Models ◽  
Stress Concentrations ◽  
Surgical Suture ◽  
Knot Security

Background: Knot tying is considered a basic surgical skill, however, there is no consensus on the best technique. Suture breakage and slippage are failure modes during surgical repair and are related to stress concentrations which cannot be easily established with physical testing. Few computational models exist that describe the effect of knot topology on the failure mechanism. The purpose of this study was to implement the finite element method to analyze the mechanical behavior of surgical sutures according to number of throws and to validate the model against experiments. Methods: Experiments and models of monofilament and multifilament sutures were conducted. Multiple throw knots were tested to failure in a laboratory setting and with corresponding finite element models. Gross loads were compared when the knot reached a localized material yield stress in the model or when failure occurred in laboratory tests that have the same suture topology. Results: The results of laboratory tests and corresponding finite element models of single throw knots were compared and found to be well correlated and consistent with existing literature in strength prediction and failure location. Moreover, single throw knots have reduced failure strengths relative to non-knotted suture approximately by 120 N for both monofilament and multifilament sutures, respectively. Clinical Relevance: This paper describes a model which can describe the initial failure process leading to knot failure. In addition, the model can evaluate the effect of knot topology on the mechanics of surgical suture. Numerically, no assessment has been completed of knot security (i.e., how likely the knot is to untie), therefore, clinical recommendations are premature. In the future, the results may provide a framework for choosing the suture and knot types for soft tissue repairs.

Nonlinear Numerical Analysis of SRC Frame Middle Joints

2013 ◽  
Vol 376 ◽  
pp. 231-235
Author(s):  
Cheng Li ◽  
Yun Zou ◽  
Jie Kong ◽  
Zhi Wei Wan
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Bearing Capacity ◽  
Axial Load ◽  
Load Ratio ◽  
Experimental Results ◽  
Steel Ratio ◽  
Finite Element Software ◽  
Axial Load Ratio ◽  
Hysteretic Performance

Nonlinear numerical analysis for the force performance of frame middle joint is processed in this paper with the finite element software of ABAQUS. Compared with experimental results, numerical analysis results are found to be reasonable. Then the influence of factors such as shaped steel ratio and axial-load ratio are contrastively analyzed. The results show that shaped steel ratio has a greater influence on the bearing capacity and hysteretic performance of the structure, but the axial-load ratio has less influence.

A Numerical Analysis for Cracks Emanating from a Quarter-Spherical Cavity on the Edge of an Elastic Body

2012 ◽  
Vol 499 ◽  
pp. 243-247
Author(s):  
Long Hai Yan ◽  
Bao Liang Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Elastic Body ◽  
Spherical Cavity ◽  
Numerical Results ◽  
Shielding Effect ◽  
Corner Crack ◽  
Element Method

This note is specifically concerned with cracks emanating from a quarter-spherical cavity on the edge in an elastic body (see Fig.1) by using finite element method. The numerical results show that the existence of the cavity has a shielding effect of the corner crack. In addition, it is found that the effect of boundaries parallel to the crack on the SIFs is obvious when.H/R≤3

Experimental and Numerical Plastic Response and Failure of Laterally Impacted Rectangular Plates

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
B. Liu ◽  
R. Villavicencio ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Failure Modes ◽  
Mesh Size ◽  
Plastic Behavior ◽  
Finite Element Models ◽  
Rectangular Plates ◽  
Marine Structures ◽  
Fine Mesh ◽  
The Impact

Experimental and numerical results of drop weight impact test are presented on the plastic behavior and fracture of rectangular plates stuck laterally by a mass with a hemispherical indenter. Six specimens were tested in order to study the influence of the impact velocity and the diameter of the indenter. The impact scenarios could represent abnormal actions on marine structures, such as ship collision and grounding or dropped objects on deck structures. The tests are conducted on a fully instrumented impact tester machine. The obtained force-displacement response is compared with numerical simulations, performed by the LS-DYNA finite element solver. The simulations aim at proposing techniques for defining the material and restraints on finite element models which analyze the crashworthiness of marine structures. The mesh size and the critical failure strain are predicted by numerical simulations of the tensile tests used to obtain the mechanical properties of the material. The experimental boundary conditions are modeled in order to represent the reacting forces developed during the impact. The results show that the critical impact energy until failure is strongly sensitive to the diameter of the striker. The shape of the failure modes is well predicted by the finite element models when a relatively fine mesh is used. Comments on the process of initiation and propagation of fracture are presented.

Two-Dimensional Finite Element Analysis of Laboratory Seawall Model

2014 ◽  
Vol 580-583 ◽  
pp. 2134-2140
Author(s):  
Jian Zhang ◽  
Jian Feng Zhai ◽  
Xian Mei Wang ◽  
Jie Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Numerical Results ◽  
Experimental Results ◽  
Base Layer ◽  
Two Dimensional ◽  
Element Analysis ◽  
Cemented Sand ◽  
Dimensional Finite Element

Two-Dimensional finite element analysis was used to investigate the performance of seawall construction over weak subgrade soil using artificial base layer material consisted of cemented sand cushion comprising geosynthetics materials. Two types of base layer materials pure sand and cemented sand comprising husk rich ash and two types of geosynthetics materials geogrid and geotextile were used. Constitutive models were used to represent different materials in numerical analysis. The competence of two-dimensional numerical analysis was compared with experimental results. Numerical results showed a superior harmony with the experimental results. Finite element analysis model proved to be a great tool to determine the parameters that are difficult to measure in laboratory experiments. In addition, finite element analysis has the benefit of cost and time saving when compared to experimental investigation work. Numerical results showed strain induced in geosynthetics eliminated beyond a distance approximately equal six times of footing width.

Axial impact behaviors of stub concrete-filled square steel tubes

2019 ◽  
Vol 22 (11) ◽  
pp. 2490-2503 ◽  
Author(s):  
YT Zhang ◽  
B Shan ◽  
Y Xiao
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Steel Tube ◽  
Experimental Results ◽  
Parameter Analysis ◽  
Steel Tubes ◽  
Simple Method ◽  
Concrete Filled Steel Tube ◽  
Drop Weight ◽  
The Impact

Existing research on the widely used concrete-filled steel tubes is mainly focused on static or cyclic loading, and the studies on effects of high strain rate are relatively rare. In this article, seven stub concrete-filled steel tubular columns with square section were tested under both static and impact loads, using a large-capacity drop-weight testing machine. The research parameters were variable height of the drop-weight and different load types. The experimental results show that the failure modes of the concrete-filled steel tube columns from the impact tests are similar with those under static load, characterized by the local buckling of the steel tube. The time history curves of impact force and steel strain were investigated. The results indicate that with increasing impact energy, the concrete-filled steel tube stub columns had a stronger impact-resistant behavior. The dynamic analysis software LS-DYNA was employed to simulate the impact behaviors of the concrete-filled steel tube specimens, and the finite element results were reasonable compared with the test results. The parameter analysis on the impact behavior of concrete-filled steel tube columns was performed using the finite element model as well. A simple method was proposed to calculate the impact strength of square concrete-filled steel tube columns and compared favorably with experimental results.

Hysteretic Behavior of Composite Vertical Connection Structures used in Prefabricated Shear Wall Systems

2020 ◽  
Vol 20 (06) ◽  
pp. 2040007
Author(s):  
Limeng Zhu ◽  
Haipeng Yan ◽  
Po-Chien Hsiao ◽  
Jianhua Zhang
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Shear Walls ◽  
High Strength ◽  
Shear Wall ◽  
Hysteretic Behavior ◽  
Design Standards

An innovative composite vertical connecting structure (CVC) with capacity carrying and energy-dissipating ability is proposed in this study, which could be used in prefabricated composite shear wall structural systems to enhance the resilience and seismic performance of structural system. The CVC structure is mainly composed of three parts, including the connecting zone, the capacity bearing zone characterized by high strength and elastic deforming ability, and the energy-dissipating zone assembled by replaceable metal dampers. The low-yield strength steel and high-strength steel are used, respectively, for the metal dampers in the energy-dissipating zone and the concrete-filled high-strength steel tubes in the bearing capacity zone to enhance the energy dissipation and self-centering abilities of CVC structures. The working mechanism is analyzed and validated through finite element models built in ABAQUS. The hysteretic behavior is simulated to evaluate their performance. First, the metal dampers are designed. The theoretical and finite elemental parametric analysis are carried out. According to the simulation results, the “Z-shaped” metal dampers exhibit better energy-dissipating ability than the rectangular shape, in which the “Z-shaped” metal dampers with 45∘ show the best performance. Simultaneously, the results of the models calculated by the finite element method and theoretical analysis work very well with each other. Furthermore, seven FE models of shear walls with CVC structures are designed. Monotonic and cyclic loading simulations are conducted. The failure modes and comprehensive mechanical performance are investigated and evaluated according to their calculated force–displacement curves, skeleton curves, and ductility coefficients. The results indicate that the CVC structure delivered preferable lateral-bearing capacity and displacement ductility. Finally, according to available design standards, the lateral stiffness of CVC structures could be conventionally controlled and some practical design recommendations are discussed.

Influence of Sandwich Damping on the Loss Factor of Multi-Plies Bellows

2010 ◽  
Vol 44-47 ◽  
pp. 2998-3002 ◽  
Author(s):  
Wei Ma ◽  
Yong Chao Lu ◽  
Yong Gang Liu ◽  
Ji Shun Li ◽  
Yu Jun Xue
Keyword(s):  
Finite Element ◽  
Loss Factor ◽  
Strain Energy ◽  
Vibration Isolation ◽  
Mechanical Performance ◽  
Finite Element Models ◽  
Modal Strain Energy ◽  
Modal Strain Energy Method ◽  
Thin Walled ◽  
Strain Energy Method

Multi-plies bellows is a kind of cylindrical thin-walled container with curved shape. It is effective in seal, energy storage and vibration isolation. In the paper, the modal loss factor of multi-plies bellows was analyzed based on the modal strain energy method. Then the finite element models of multi-piles bellows were given by ANSYS. The mechanical performance of bellows was analyzed in detail. The strain energy distribution of multi-plies bellows and viscoelsticity layer were given. According to the strain energy, the influence of sandwich damping on the loss factor was studied. The results show that the loss factor can be improved by employing the sandwich damping with big thickness and elastic modulus 200MPa.

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