scholarly journals Effect of Uncertainties in Material and Structural Detailing on the Seismic Vulnerability of RC Frames Considering Construction Quality Defects

2020 ◽  
Vol 10 (24) ◽  
pp. 8832
Author(s):  
Siyun Kim ◽  
Taehwan Moon ◽  
Sung Jig Kim
Keyword(s):  
Material Properties ◽  
Seismic Vulnerability ◽  
Concrete Strength ◽  
Transverse Reinforcement ◽  
Construction Quality ◽  
Uncertain Variables ◽  
Rc Frames ◽  
Structural Detailing ◽  
Global And Local ◽  
The Impact

This paper evaluates the effect of construction quality defects on the seismic vulnerability of reinforced concrete (RC) frames. The variability in the construction quality of material properties and structural detailing is considered to assess the effect on the seismic behavior of RC frames. Concrete strength and yield strength of the reinforcement are selected as uncertain variables for the material properties, while the variabilities in the longitudinal reinforcement ratio and the volumetric ratio of transverse reinforcement are employed for structural detailing. Taking into account the selected construction quality uncertainties, the sensitivity analysis of the seismic vulnerability of the RC frames is performed and the impact of significant parameters is assessed at the global and local levels. This extensive analytical study reveals that the seismic vulnerability of the selected RC frame is particularly sensitive to concrete strength and the volumetric ratio of transverse reinforcement.

Response of Dolos Concrete Armor Units to Impact Loads

1991 ◽  
Vol 113 (4) ◽  
pp. 286-291 ◽  
Author(s):  
J. W. Tedesco ◽  
P. B. McGill ◽  
W. G. McDougal
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Concrete Strength ◽  
Impact Resistance ◽  
Nonlinear Material ◽  
Impact Loads ◽  
Model Formulation ◽  
Element Analysis ◽  
The Impact

A finite element analysis is conducted to determine the critical impact velocities for concrete dolos. The model formulation includes deformations at the contact surface and nonlinear material properties. Two dolos orientations are considered: vertical fluke seaward and horizontal fluke seaward. In both cases, the larger units fail at lower angular impact velocities. It is also shown that doubling the concrete strength increases the impact resistance by approximately 40 percent.

scholarly journals Fragility assessment of existing low-rise steel moment-resisting frames with masonry infills under mainshock-aftershock earthquake sequences

2021 ◽  
Vol 19 (6) ◽  
pp. 2483-2504
Author(s):  
Luigi Di Sarno ◽  
Jing-Ren Wu
Keyword(s):  
Seismic Vulnerability ◽  
Steel Frames ◽  
Steel Frame ◽  
Second Phase ◽  
Moment Frames ◽  
Damage Level ◽  
Masonry Infills ◽  
Aftershock Sequences ◽  
The Impact ◽  
Multiple Earthquakes

AbstractThis paper presents the fragility assessment of non-seismically designed steel moment frames with masonry infills. The assessment considered the effects of multiple earthquakes on the damage accumulation of steel frames, which is an essential part of modern performance-based earthquake engineering. Effects of aftershocks are particularly important when examining damaged buildings and making post-quake decisions, such as tagging and retrofit strategy. The procedure proposed in the present work includes two phase assessment, which is based on incremental dynamic analyses of two refined numerical models of the case-study steel frame, i.e. with and without masonry infills, and utilises mainshock-aftershock sequences of natural earthquake records. The first phase focuses on the undamaged structure subjected to single and multiple earthquakes; the effects of masonry infills on the seismic vulnerability of the steel frame were also considered. In the second phase, aftershock fragility curves were derived to investigate the seismic vulnerability of infilled steel frames with post-mainshock damage caused by mainshocks. Comparative analyses were conducted among the mainshock-damaged structures considering three post-mainshock damage levels, including no damage. The impact of aftershocks was then discussed for each mainshock-damage level in terms of the breakpoint that marks the onset of exceeding post-mainshock damage level, as well as the probability of exceeding of superior damage level due to more significant aftershocks. The evaluation of the efficiency of commonly used intensity measures of aftershocks was also carried out as part of the second phase of assessment.

Probing the impact of material properties of core-shell SiO2@TiO2 spheres on the plasma-catalytic CO2 dissociation using a packed bed DBD plasma reactor

2021 ◽  
Vol 46 ◽  
pp. 101468
Author(s):  
Periyasamy Kaliyappan ◽  
Andreas Paulus ◽  
Jan D’Haen ◽  
Pieter Samyn ◽  
Yannick Uytdenhouwen ◽  
...  
Keyword(s):  
Material Properties ◽  
Plasma Reactor ◽  
Packed Bed ◽  
Core Shell ◽  
Dbd Plasma ◽  
The Impact

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

Dynamic Response of a Generic Vehicle Floor Model to Coupled Transient Loads

1996 ◽  
Author(s):  
Aaron D. Gupta
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Response Analysis ◽  
Impact Loads ◽  
Valuable Insight ◽  
Concentrated Load ◽  
Shell Elements ◽  
Transient Loads ◽  
Method Of Evaluation ◽  
The Impact

Abstract A dynamic elastic large displacement response analysis of the bottom floor of a generic vehicle hull model subjected to empirically obtained coupled blast and impact loads has been conducted using three-dimensional (3-D) shell elements in the ADINA nonlinear dynamic finite element analysis code. For the impulse-dominated problem, the impact load is a square wave step function concentrated load while the blast loads from the detonation of an explosive are a series of distributed pressure loads approximated as triangular impulse loads with linear decay and varying arrival and duration times. The 3-D numerical model has been generated using the PATRAN3 modeling code and converted to the ADINA finite element input data deck using the ADINA translator and careful inclusion of appropriate material properties as well as initial and boundary conditions. Monolithic single-layered four-noded quad shell elements were sufficient to model the bottom floor and the left- and right-horizontal and vertical sponsons as well as the lower front glacis. Although several simplifying assumptions and approximations are made during the generation of the basic floor model, material properties, and the forcing functions, the investigation gives valuable insight into the response behavior of a generic hull bottom floor to externally applied coupled blast and impact loads and provides an inexpensive nondestructive method of evaluation of the structural integrity of modern vehicles subjected to spatially varying transient loads.

SIMULATION OF DYNAMIC EVENT OF IMPACT USING EXPLICIT 3D FEM MODEL AND VALIDATION BY EXPERIMENT AND CONTACT MODELS

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Akshay Mallikarjuna ◽  
Dan Marghitu ◽  
P.K. Raju
Keyword(s):  
Material Properties ◽  
Permanent Deformation ◽  
Oblique Impact ◽  
Coefficient Of Restitution ◽  
Impact Behavior ◽  
3D Fem ◽  
Dynamic Event ◽  
Contact Models ◽  
Explicit Dynamic ◽  
The Impact

— In this study, an optimized method to simulate the dynamic 3D event of the impact of a rod with a flat surface has been presented. Unlike the 2D FEM based contact models, in this study both the bodies undergoing the impact are considered elastic(deformable) and simulation is the dynamic event of the impact, instead of predefined 2D symmetric contact analysis. Prominent contact models and plasticity models to define material properties in ANSYS are reviewed. Experimentation results of normal and oblique impact of the rod for different rods provided the coefficient of restitution. Experimental results of permanent deformation on the base for different impact velocity is derived out of a prominent impact study. The simulation results are in co-relation with experiment and both indentation and flattening models on the coefficient of restitution (COR) and permanent deformation of the base and rod after the impact. Thus, the presented 3D Explicit Dynamic simulation of impact is validated to analyze the impact behavior of the 2 bodies without any predefined assumptions with respect to boundary conditions or material properties.

A Review on Non-Asbestos Friction Materials: Material Composition and Manufacturing

2018 ◽  
Vol 1150 ◽  
pp. 22-42
Author(s):  
Dinesh Shinde ◽  
Kishore N. Mistry ◽  
Suyog Jhavar ◽  
Sunil Pathak
Keyword(s):  
Composite Materials ◽  
Material Properties ◽  
Single Phase ◽  
Friction Material ◽  
Material Surface ◽  
Surface Wear ◽  
Friction Modifier ◽  
Friction Materials ◽  
Morphological Studies ◽  
The Impact

The peculiar feature of friction materials to absorb the kinetic energy of rotating wheels of an automobile to control the speed makes them remarkable in automobile field. The regulation of speed cannot be achieved with the use of single phase material as a friction material. Consequently, the friction material should be comprised of composite materials which consist of several ingredients. Incidentally, the friction materials were formulated with friction modifier, binders, fillers and reinforcements. Due to its pleasant physical properties, asbestos was being used as a filler. Past few decades, it is found that asbestos causes dangerous cancer to its inhaler, which provides a scope its replacement. Several attempts have been made to find an alternative to the hazardous asbestos. The efforts made by different researchers for the impact of every composition of composite friction material in the field are reviewed and studied for their effect on the properties of friction material. Surface morphological studies of different friction material are compared to interpret the concept of surface wear and its correlation with material properties.

Mechanical Event Simulation of Drop Testing for Toy Product

2006 ◽  
Vol 532-533 ◽  
pp. 993-996
Author(s):  
Anthony Yee Kai Yam ◽  
Kai Leung Yung ◽  
Chi Wo Lam
Keyword(s):  
Material Properties ◽  
Impact Analysis ◽  
Plastic Material ◽  
Free Fall ◽  
Drop Impact ◽  
Local Analysis ◽  
Element Analysis ◽  
Event Simulation ◽  
Long Time ◽  
The Impact

Toys that are free from drop failures normally take a long time to develop. It is often time and cost consuming after the production tooling is built to detect drop test failure. This paper introduces a new drop testing analysis method for Toys. The method uses a simple approach with a local analysis that based on the linear and non linear finite element analysis. Modeling and transient drop analysis of a pre-school toy is used as a case study to demonstrate the method. The impact analysis of the product hitting the solid concrete floor after a free fall is presented. The analysis focuses on the deformation of the housing for a product with electronic circuit and mechanical mechanism inside. Experimental data has been obtained for drop simulation of the housing and its correlation with the plastic material properties. The stress and strain of the housing during drop impact tests are noted. The effects of the material properties to the housing deflection under drop/impact shock have been investigated. Numerical results are compared with experimental results to validate the method.

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