scholarly journals A preliminary analysis and discussion of the condominium building collapse in surfside, Florida, US, June 24, 2021

2021 ◽  
Author(s):  
Xinzheng Lu ◽  
Hong Guan ◽  
Hailin Sun ◽  
Yi Li ◽  
Zhe Zheng ◽  
...  
Keyword(s):  
Preliminary Analysis ◽  
Building Design ◽  
Punching Shear ◽  
Design Codes ◽  
Element Analysis ◽  
Building Collapse ◽  
Structure Building ◽  
Overall Performance ◽  
Collapsed Building ◽  
Collapse Process

AbstractOn June 24, 2021, a 40-year-old reinforced concrete flat plate structure building in Miami suffered a sudden partial collapse. This study analyzed the overall performance and key components of the collapsed building based on the building design codes (ACI-318 and GB 50010). Punching shear and post-punching performances of typical slab-column joints are also studied through the refined finite element analysis. The collapse process was simulated and visualized using a physics engine. By way of these analyses, weak design points of the collapsed building are highlighted. The differences between the reinforcement detailing of the collapsed building and the requirements of the current Chinese code are discussed, together with a comparison of the punching shear and post-punching performances. The simulated collapse procedure and debris distribution are compared with the actual collapse scenes.

Research on the Piezoelectric Ultrasonic Actuator Applied to SFSS

2015 ◽  
Author(s):  
Y. J. Tang ◽  
Z. Yang ◽  
X. J. Wang ◽  
J. Wang
Keyword(s):  
Natural Vibration ◽  
Structural Parameters ◽  
Laser Vibrometer ◽  
Vibration Modes ◽  
Element Analysis ◽  
Linear Type ◽  
Frequency Sweep ◽  
The Finite Element Analysis ◽  
Frequency Sweep Test ◽  
Overall Performance

This paper presents an investigation of a novel linear-type piezoelectric ultrasonic actuator for application in a Smart Fuze Safety System (SFSS). Based on the requirements of SFSS, the structural parameters of the proposed piezoelectric ultrasonic actuator are determined by fuze arming mode. Moreover, sensitivity analysis of the structural parameters to the frequency consistency is conducted using FEM software, after which the optimal dimensions are obtained with two close natural vibration frequencies. To validate the results of FEM, the frequency sweep tests of the piezoelectric ultrasonic actuator are performed to determine the motor’s actual working mode frequencies with PSV-300-B Doppler laser vibrometer system. Furthermore, the results of frequency sweep test are compared with that of the finite element analysis, and further verified by impedance analyzer. To investigate the overall performance of the piezoelectric ultrasonic actuator, vibration modes of actuator’s stator, output speed and force of the piezoelectric ultrasonic actuator are tested. The experimental results show that the output speed and force of the actuator can reach 88.2 mm/s and 2.3N respectively, which means that piezoelectric ultrasonic actuator designed in this paper can meet the demands of the SFSS.

scholarly journals Use of 3D Scan of Weld Joint in Finite Element Analysis and Stochastic Analysis of Hot-Spot Stresses in Tubular Joint for Fatigue Life Estimation

2019 ◽  
Author(s):  
Mikkel L. Larsen ◽  
Vikas Arora ◽  
Marie Lützen ◽  
Ronnie R. Pedersen ◽  
Eric Putnam
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Welded Joints ◽  
Hot Spot ◽  
Strain Range ◽  
Fe Model ◽  
Design Codes ◽  
Element Analysis ◽  
Hot Spot Stress ◽  
Weld Toe

Abstract Several methods for modelling and finite element analysis of tubular welded joints are described in various design codes. These codes provide specific recommendations for modelling of the welded joints, using simple weld geometries. In this paper, experimental hot-spot strain range results from a full-scale automatically welded K-node test are compared to corresponding finite element models. As part of investigating the automatically welded K-joint, 3D scans of the weld surfaces have been made. These scans are included in the FE models to determine the accuracy of the FE models. The results are compared to an FE model with a simple weld geometry based on common offshore design codes and a model without any modelled weld. The results show that the FE model with 3D scanned welds is more accurate than the two simple FE models. As the weld toe location of the 3D scanned weld is difficult to locate precisely in the FE model and as misplacement of strain gauges are possible, stochastic finite element modelling is performed to analyse the resulting probabilistic hot-spot stresses. The results show large standard deviations, showing the necessity to evaluate the hot-spot stress method when using 3D scanned welds.

Numerical Analysis of Punching Shear Failure of Self-Compacting Fiber Reinforced Concrete (SCFRC) Ribbed Slabs

2019 ◽  
Vol 972 ◽  
pp. 93-98
Author(s):  
Nurulain Hanida Mohamad Fodzi ◽  
M.H. Mohd Hisbany
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Nonlinear Finite Element ◽  
Fiber Reinforced Concrete ◽  
Punching Shear ◽  
Nonlinear Finite Element Method ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Abaqus Software

This paper deals with behavior and capacity of punching shear resistance for ribbed slabs produce from self-compacting fiber reinforced concrete (SCFRC) by application of nonlinear finite element method. The analysis will be achieved by using ABAQUS software. The nonlinear finite element analysis by ABAQUS will be compare with the experimental results. Results and conclusions may be useful for establishing recommendation and need to be acknowledged.

The Finite-Element Analysis of the Main Frame of the Airborne Photoelectric Platform

2012 ◽  
Vol 562-564 ◽  
pp. 1943-1946
Author(s):  
Yong Hu ◽  
Jin Gan Song ◽  
Qing Zou ◽  
Ke Zhu ◽  
Xiao Long Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Weak Links ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Overall Performance ◽  
Sufficient Strength ◽  
Ansys Workbench ◽  
Main Frame

Because both of the volume and the weight of the photoelectric platform are small, the structure of two frames and two axes is used in the photoelectric platform. As the key component of the photoelectric platform, the main frame should have sufficient strength and rigidity. In order to achieve this object, three-dimensional entity model of the main frame is established using CATIA software. Then the finite-element analysis of the model is finished with ANSYS Workbench. Based on the analysis results, the weak links of the main frame is found. Then these links are improved and the main frame is analyzed again. After improving the structure, the results of the finite-element analysis show that the main frame meets the requirements of design and has perfect overall performance.

Structural Design and Finite Element Analysis of Unfolding Process for All Composite Folding Wing of UAV

2010 ◽  
Vol 163-167 ◽  
pp. 2328-2332 ◽  
Author(s):  
Peng Lv ◽  
Sheng Li Lv ◽  
Guang Jun Yang ◽  
Qing Na Zeng ◽  
Xiao Yan Tong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Design ◽  
Third Order ◽  
Element Analysis ◽  
Impact Action ◽  
Flutter Analysis ◽  
Folding Wing ◽  
Overall Performance ◽  
Composite Wing

This paper discusses the unfolding form of the folding wing and its application to special UAV. The main investigations involve aspects such as unfolding process of the special UAV’s folding wing, contour structure of the complete unfolding, the choice of composite materials for the folding wing and its overall performance parameters. Modeling and dynamics analysis are made for all-composite wing through finite element analysis and calculating software. The unfolding process is also simulated. The result shows that the wing’s first-order frequency is low, second-order frequency and third-order frequency are close at different sweep angles. The wings are apt to happen flutter coupling in flutter analysis. With the continued folding of the wing, the wing’s natural frequency decreases significantly at different orders. The conclusions can provide effective basis for the study of wing rotational rate, unfolding time and impact action.

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