scholarly journals Prediction of Damage Level of Slab-Column Joints under Blast Load

2020 ◽  
Vol 10 (17) ◽  
pp. 5837
Author(s):  
Kwang Mo Lim ◽  
Do Guen Yoo ◽  
Bo Yeon Lee ◽  
Joo Ha Lee
Keyword(s):  
Numerical Analysis ◽  
Prediction Equation ◽  
General Purpose ◽  
Blast Loads ◽  
Joint Region ◽  
Element Analysis ◽  
Scaled Distance ◽  
Damage Level ◽  
Disturbed Zone ◽  
Column Joint

The behavior of a slab-column joint subjected to blast loads was studied by numerical analysis using a general-purpose finite element analysis program, LS-DYNA. Under the explosive load, the joint region known as the stress disturbed zone was defined as a region with a scaled distance of 0.1 m/kg1/3 or less through comparison with ConWep’s empirical formula. Displacement and support rotation according to Trinitrotoluene (TNT) weight and scaled distance were investigated by dividing in and out of the joint region. In addition, fracture volume was newly proposed as an evaluation factor for blast-resistant performance, and it was confirmed that the degree of damage to a member due to blast loads was well represented by the fracture volume. Finally, a prediction equation for the blast-resistant performance of the slab-column joint was proposed, and the reliability and accuracy of the equation were verified through additional numerical analysis.

scholarly journals Numerical Simulation on Dynamic Behavior of Slab–Column Connections Subjected to Blast Loads

2021 ◽  
Vol 11 (16) ◽  
pp. 7573
Author(s):  
Kwang Mo Lim ◽  
Taek Hee Han ◽  
Joo Ha Lee
Keyword(s):  
Numerical Analysis ◽  
Blast Resistance ◽  
Mesh Size ◽  
Material Model ◽  
Simulation Method ◽  
Blast Load ◽  
Blast Loads ◽  
Element Analysis ◽  
Model And Simulation ◽  
Resistance Performance

Although many studies on the blast-resistant performance of structures have focused mainly on single members such as beams and columns, there is little research on the behavior of joints that are subjected to blast loads. In this study, the structural behavior of a slab–column connection subjected to blast load was investigated using a numerical analysis method. LS-DYNA was used as a finite element analysis program, and in order to improve the accuracy of numerical analysis, mesh size, material model, and simulation method of blast load were determined through preliminary analysis. The effect of different restraints of the joints, depending on the position of the columns in the slab, on the blast resistance performance was investigated. As a result, the highly confined slab-interior column connection showed better behavior than other edge and corner columns. The drop panel installed between the lower column and the slab was effective in improving the blast-resistance performance of the slab–column connection. For a more accurate evaluation of blast resistance performance, it was suggested that various evaluation factors such as ductility ratio, reinforcing stress, and concrete fracture area can be considered along with the support rotation, which is an important evaluation factor suggested by many standards.

Rubber Composition–Properties Relationships during Tire Numerical Simulation and Design Optimization

2017 ◽  
Vol 45 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Alexey Mazin ◽  
Alexander Kapustin ◽  
Mikhail Soloviev ◽  
Alexander Karanets
Keyword(s):  
Numerical Simulation ◽  
Design Optimization ◽  
Strain Tensor ◽  
General Purpose ◽  
Orthogonal Functions ◽  
Element Analysis ◽  
Time Investment ◽  
Footprint Analysis ◽  
Composition Properties ◽  
Nonlinear Elastic

ABSTRACT Numerical simulation based on finite element analysis is now widely used during the design optimization of tires, thereby drastically reducing the time investment in the design process and improving tire performance because it is obtained from the optimized solution. Rubber material models that are used in numerical calculations of stress–strain distributions are nonlinear and may include several parameters. The relations of these parameters with rubber formulations are usually unknown, so the designer has no information on whether the optimal set of parameters is reachable by the rubber technological possibilities. The aim of this work was to develop such relations. The most common approach to derive the equation of the state of rubber is based on the expansion of the strain energy in a series of invariants of the strain tensor. Here, we show that this approach has several drawbacks, one of which is problems that arise when trying to build on its basis the quantitative relations between the rubber composition and its properties. An alternative is to use a series expansion in orthogonal functions, thereby ensuring the linear independence of the coefficients of elasticity in evaluation of the experimental data and the possibility of constructing continuous maps of “the composition to the property.” In the case of orthogonal Legendre polynomials, the technique for constructing such maps is considered, and a set of empirical functions is proposed to adequately describe the dependence of the parameters of nonlinear elastic properties of general-purpose rubbers on the content of the main ingredients. The calculated sets of parameters were used in numerical tire simulations including static loading, footprint analysis, braking/acceleration, and cornering and also in design optimization procedures.

Column Moment Demands from Orthogonal Beam Twisting

2018 ◽  
Vol 763 ◽  
pp. 259-269
Author(s):  
George Webb ◽  
Kanyakon Kosinanonth ◽  
Tushar Chaudhari ◽  
Saeid Alizadeh ◽  
Gregory A. MacRae
Keyword(s):  
Lateral Displacement ◽  
Frame Structure ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Element Analysis ◽  
Soft Storey ◽  
Simply Supported ◽  
Composite Frame ◽  
Explicit Consideration ◽  
Column Joint

Beam column joint subassemblies in steel moment frames often have simply-supported gravity beams framing into the joint in the perpendicular direction. When these subassemblies undergo lateral displacement, moments enter the column from the beams. Some of these moments are directly applied from the in-plane beam and slab stresses as they contact the column, and additional moments occur as the slab causes the perpendicular simply supported beams to twist. In most design codes around the world, no explicit consideration of these moments is performed even though they may increase the likelihood of column yielding and a soft-storey mechanism. This paper quantifies the magnitude of these perpendicular beam twisting moments in typical subassemblies using inelastic finite element analysis. It is shown that for beam-column-joint-slab subassemblies where the primary and secondary beams are fully welded to the column, the addition of slab effects significantly increases the total stiffness and strength of the composite frame structure. In addition to this, it is also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 2% for an imposed drift of 5% for the subassembly investigated when no gap was provided between slab and the column. It was also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 10% for a maximum imposed drift of 5% for the subassembly investigated when a gap was provided between the slab and the column.

scholarly journals Analysis of Non-Uniform Shrinkage Effect in Box Girder Sections for Long-Span Continuous Rigid Frame Bridge

2018 ◽  
Vol 13 (2) ◽  
pp. 146-155 ◽  
Author(s):  
Zhuoya Yuan ◽  
Pui-Lam Ng ◽  
Darius Bačinskas ◽  
Jinsheng Du
Keyword(s):  
Finite Element ◽  
General Purpose ◽  
Element Analysis ◽  
Box Girder ◽  
Finite Element Program ◽  
Continuous Rigid Frame Bridge ◽  
Rigid Frame ◽  
Shrinkage Effect ◽  
Rigid Frame Bridge

To consider the effect of non-uniform shrinkage of box girder sections on the long-term deformations of continuous rigid frame bridges, and to improve the prediction accuracy of analysis in the design phase, this paper proposes a new simulation technique for use with general-purpose finite element program. The non-uniform shrinkage effect of the box girder is transformed to an equivalent temperature gradient and then applied as external load onto the beam elements in the finite element analysis. Comparative analysis of the difference in deflections between uniform shrinkage and nonuniform shrinkage of the main girder was made for a vehicular bridge in reality using the proposed technique. The results indicate that the maximum deflection of box girder under the action of non-uniform shrinkage is much greater than that under the action of uniform shrinkage. The maximum downward deflection of the bridge girder caused by uniform shrinkage is 5.6 mm at 20 years after completion of bridge deck construction, whereas the maximum downward deflection caused by non-uniform shrinkage is 21.6 mm, which is 3.8 times larger. This study shows that the non-uniform shrinkage effect of the girder sections has a significant impact on the long-term deflection of continuous rigid frame bridge, and it can be accurately simulated by the proposed transformation technique.

scholarly journals Finite Element Analysis of Artificially Frozen C-Phi soil

2019 ◽  
Vol 8 (4) ◽  
pp. 12722-12728
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Frozen Soil ◽  
Experimental Results ◽  
Soil Freezing ◽  
Strength Parameter ◽  
Frozen Ground ◽  
Element Analysis ◽  
Test Setup ◽  
Geological Conditions

Artificial Ground Freezing techniques eliminate the need for structural supports during the course of an excavation, as frozen ground is solid and waterproof. At present, it is adopted as an effective way to deal with various construction ground control challenges such as the mitigation of seepage infiltration into tunnels and shaft excavations; or ground strengthening for excavation. In-depth knowledge of the frozen soil characteristics through experiments and the development of suitable constitutive models that suit the geological conditions of our country are necessary to predict the strength and behavior of the frozen soils. Numerical analysis of frozen soil can be used for mass works like tunneling which cannot be experimentally verified. This paper presents a validation of experimental results obtained from laboratory setup and soil freezing system for C-Phi soil. The main aim is to compare numerical and experimental results and hence obtaining the shear strength parameter of the soil, similar to the conventional triaxial test setup. To perform numerical analysis Finite element tool ANSYS 19 is used. Soil model is made in ANSYS 19 and required loads are inputted to performed the analysis similar to the experimental method. The result obtained from experimental test setup and numerical analysis was verified and compared and it was found that values of numerical results lies closer to experimental results

scholarly journals A Review on Numerical Analysis of RC Flat Slabs Exposed to Fire

2020 ◽  
Vol 27 (1) ◽  
pp. 1-5
Author(s):  
Hanadi Naji ◽  
Nibras Khalid ◽  
Mutaz Medhlom
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Bending Moment ◽  
Mechanical And Thermal Properties ◽  
Vertical Deflection ◽  
Element Analysis ◽  
Flat Slabs ◽  
Numerical Studies ◽  
The Finite Element Analysis

This paper aims at presenting and discussing the numerical studies performed to estimate the mechanical and thermal behavior of RC flat slabs at elevated temperature and fire. The numerical analysis is carried out using finite element programs by developing models to simulate the performance of the buildings subjected to fire. The mechanical and thermal properties of the materials obtained from the experimental work are involved in the modeling that the outcomes will be more realistic. Many parameters related to fire resistance of the flat slabs have been studied and the finite element analysis results reveal that the width and thickness of the slab, the temperature gradient, the fire direction, the exposure duration and the thermal restraint are important factors that influence the vertical deflection, bending moment and force membrane of the flat slabs exposed to fire. However, the validation of the models is verified by comparing their results to the available experimental date. The finite element modeling contributes in saving cost and time consumed by experiments.

Development of a High Cycle Fatigue Life Prediction Model for Thin Film Silicon Structures

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Chia-Cheng Chang ◽  
Sheng-Da Lin ◽  
Kuo-Ning Chiang
Keyword(s):  
Thin Film ◽  
Fatigue Life ◽  
Life Prediction ◽  
Microelectromechanical Systems ◽  
Fatigue Testing ◽  
Mesh Size ◽  
Prediction Equation ◽  
Frequency Effect ◽  
Element Analysis ◽  
Solution Type

The fatigue characteristics of microelectromechanical systems (MEMS) material, such as silicon or polysilicon, have become very important. Many studies have focused on this topic, but none have defined a good methodology for extracting the applied stress and predicting fatigue life accurately. In this study, a methodology was developed for the life prediction of a polysilicon microstructure under bending tests. Based on the fatigue experiments conducted by Hocheng et al. (2008, “Various Fatigue Testing of Polycrystalline Silicon Microcantilever Beam in Bending,” Jpn. J. Appl. Phys., 47, pp. 5256–5261) and (Hung and Hocheng, 2012, “Frequency Effects and Life Prediction of Polysilicon Microcantilever Beams in Bending Fatigue,” J. Micro/Nanolithogr., MEMS MOEMS, 11, p. 021206), cantilever beams with different dimensions were remodeled with mesh control technology using finite element analysis (FEA) software to extract the stress magnitude. The mesh size, anchor boundary, loading boundary, critical stress definition, and solution type were well modified to obtain more correct stress values. Based on the new stress data extracted from the modified models, the optimized stress-number of life curve (S–N curve) was obtained, and the new life-prediction equation was found to be referable for polysilicon thin film life prediction under bending loads. After comparing the literature and confirming the new models, the frequency effect was observed only for the force control type and not for the displacement control type.

Development of Finite Element Analysis Support System Based on the Hybrid Knowledge Model

1992 ◽  
Author(s):  
S. Nagasawa ◽  
H. Sakuta ◽  
M. Goto
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Support System ◽  
System Development ◽  
Object Oriented ◽  
Data Representation ◽  
General Purpose ◽  
Element Analysis ◽  
Intelligent Support ◽  
Hierarchical Representation

Abstract This paper deals with conceptual orientation and system development of intelligent support system for general purpose FEA (finite element analysis) programs. An integrated support system called “InhierTalk” (Integrated interactive environment for hierarchical representation for FEA) has been developed in Smalltalk, an object oriented language, in order to confirm effectivity of hierarchical representation and to establish an optimum method of the system development. Two object-oriented knowledge models which consist of macro visual data representation and micro regularized data representation are proposed. In the development, it is found to be clear that active and passive evaluation methods are effective for construction of support system.

Finite Element Modeling of Non-Orthogonal Loosely Woven Fabrics in Advanced Occupant Restraint Systems

2001 ◽  
Author(s):  
Romil R. Tanov ◽  
Marlin Brueggert
Keyword(s):  
Finite Element ◽  
Material Model ◽  
General Purpose ◽  
Woven Fabrics ◽  
Element Analysis ◽  
Correct Operation ◽  
Explicit Finite Element ◽  
Analysis Scheme ◽  
Occupant Restraint Systems ◽  
Protection Devices

Abstract The behavior of loosely woven fabrics differs significantly from other types of woven fabrics. Its unique characteristics have been successfully utilized for the correct operation of some recently developed occupant protection devices for the automotive and heavy machine and truck industry. However, this behavior cannot be efficiently modeled using the currently available material models within a finite element analysis scheme. Therefore, the aim of this work is to present the basics of a formulation of a material model for the analysis of loosely woven fabrics and its implementation in a general-purpose explicit finite element code. To assess the performance of the model, results from the simulation are presented and compared to real test data.

Numerical analysis of mechanical properties of 3D printed aluminium components with variable core infill values

2020 ◽  
Vol 1 (103) ◽  
pp. 16-24
Author(s):  
P. Baras ◽  
J. Sawicki
Keyword(s):  
Numerical Analysis ◽  
Mechanical Strength ◽  
Reference Model ◽  
Reaction Force ◽  
Solid Material ◽  
Solid Core ◽  
Compression Tests ◽  
Element Analysis ◽  
Static Compression ◽  
3D Printed

Purpose: The purpose of this paper is to present numerical modelling results for 3D-printed aluminium components with different variable core infill values. Information published in this paper will guide engineers when designing the components with core infill regions. Design/methodology/approach: During this study 3 different core types (Gyroid, Schwarz P and Schwarz D) and different combinations of their parameters were examined numerically, using FEM by means of the software ANSYS Workbench 2019 R2. Influence of core type as well as its parameters on 3D printed components strength was studied. The “best” core type with the “best” combination of parameters was chosen. Findings: Results obtained from the numerical static compression tests distinctly showed that component strength is highly influenced by the type infill choice selected. Specifically, infill parameters and the coefficient (force reaction/volumetric percentage solid material) were investigated. Resulting total reaction force and percentage of solid material in the component were compared to the fully solid reference model. Research limitations/implications: Based on the Finite Element Analysis carried out in this work, it was found that results highlighted the optimal infill condition defined as the lowest amount of material theoretically used, whilst assuring sufficient mechanical strength. The best results were obtained by Schwarz D core type samples. Practical implications: In the case of the aviation or automotive industry, very high strength of manufactured elements along with a simultaneous reduction of their wight is extremely important. As the viability of additively manufactured parts continues to increase, traditionally manufactured components are continually being replaced with 3D-printed components. The parts produced by additive manufacturing do not have the solid core, they are rather filled with specific geometrical patterns. The reason of such operation is to save the material and, in this way, also weight. Originality/value: The conducted numerical analysis allowed to determine the most favourable parameters for optimal core infill configurations for aluminium 3D printed parts, taking into account the lowest amount of material theoretically used, whilst assuring sufficient mechanical strength.

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