Development of an evacuation model considering the impact of stress variation on evacuees under fire emergency

2021 ◽  
Vol 138 ◽  
pp. 105232
Author(s):  
Rui Feng Cao ◽  
Eric Wai Ming Lee ◽  
Anthony Chun Yin Yuen ◽  
Qing Nian Chan ◽  
Wei Xie ◽  
...  
Keyword(s):  
Stress Variation ◽  
Evacuation Model ◽  
The Impact

Impact Analysis of an Oxygen Mask Locking Panel of Aircraft Using Finite Element Modelling

2014 ◽  
Vol 657 ◽  
pp. 735-739 ◽  
Author(s):  
Emilian Ionut Croitoru ◽  
Gheorghe Oancea
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Impact Analysis ◽  
Element Model ◽  
Composite Panel ◽  
Cad Model ◽  
Stress Variation ◽  
Element Modelling ◽  
Oxygen Mask ◽  
The Impact

This paper presents a method of finite element modelling used for the impact analysis of a composite panel. In this research, the composite panel consists of an oxygen mask locking panel of an aircraft. This panel is loaded with one concentrated abuse loading and three uniform distributed abuse loading cases and the stress variation within the composite panel for each load case is determined. In order to assess the impact analysis on the oxygen mask panel of the aircraft, a finite element model is created using Patran as the main application for pre/post-processing and Nastran as the main processor. The paper also presents a comparison between results obtained using the same finite element modelling of the composite panel CAD model of the panel with four load cases with different material types. The results are used to determine the most capable material stresswise.

scholarly journals Vertical Shaft Support Improvement Studies by Strata Grouting at Aquifer Zone

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Qing Yu ◽  
Kexin Yin ◽  
Jinrong Ma ◽  
Hideki Shimada
Keyword(s):  
Compressive Force ◽  
Injection Pressure ◽  
Negative Influence ◽  
New Method ◽  
Stress Variation ◽  
High Injection Pressure ◽  
Shaft Lining ◽  
The Stability ◽  
The Impact ◽  
Chain Conveyor

The shaft lining failure which occurs in deep alluvium is a sudden coal mine hazard. The strata grouting is one of the treatment methods for the shaft lining failure. To investigate the impact of grout injection pressure on the shaft lining, the field measurement and the numerical analysis of the shaft lining stress variation during the grouting were conducted. To improve the strata grouting, the underground continuous impervious curtain (UCIC) is proposed as a new method by using the chain conveyor cutter technique without the impact on the shaft lining. The effects of the new method were also analyzed by means of the numerical methods. The results show that the strata grouting in the deep alluvium needs a high injection pressure, and in the horizontal direction, the shaft lining sustains the repeat tensile and compressive force during the grouting process. The negative influence of strata grouting on the stability of the shaft lining is obvious and serious. The UCIC built around the shaft lining can restrain the stress concentration induced by the aquifer drawdown. The triangular UCIC has a similar effect as that of the vertical one, and the small angle is better for preventing the shaft lining failure.

Experimental Study on Impact Resistance of Dump Truck Bodies Floor

2014 ◽  
Vol 1051 ◽  
pp. 857-861
Author(s):  
Bin Tian ◽  
Da Wei Liu ◽  
Long Long Zhu
Keyword(s):  
Finite Element Method ◽  
Experimental Study ◽  
Finite Element ◽  
Impact Loading ◽  
Impact Resistance ◽  
Test System ◽  
Dump Truck ◽  
Stress Variation ◽  
Metal Materials ◽  
The Impact

In order to study the impact resistance capability of dump truck bodies floor, a simulation model of dump truck bodies floor and impact hammerheads made of metal materials were designed, and a strain test system of bodies floor under impact loading was established, a measurement of the stress of bodies floor model was made to obtain the law of stress variation about key point of truck bodies floor model. The research laid the foundation for the analysis of impact resistance capability of dump truck bodies floor using finite element method as well as provided a reference for the structural optimization of truck bodies floor.

An Experimental Study on Fatigue Life Variance, Residual Stress Variance, and Their Correlation of Face-Turned and Ground Ti 6Al-4V Samples

2002 ◽  
Vol 124 (4) ◽  
pp. 809-819 ◽  
Author(s):  
Xiaoping Yang ◽  
C. Richard Liu ◽  
A. F. Grandt
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Manufacturing Processes ◽  
Machining Processes ◽  
Stress Variation ◽  
Bending Fatigue ◽  
New Process ◽  
The Impact ◽  
The Relationship ◽  
Stress Variance

It is well known that there is a large variance associated with fatigue life. However, in literature little is found on the relationship between manufacturing processes and fatigue variance of the manufactured components. In this research, the influence of machining processes on the fatigue variance of the machined Ti 6Al-4V samples is studied experimentally. The impact is evaluated by comparing the safety ratios of face-turned samples with those of ground samples. The safety ratio is defined as the average fatigue life over the fatigue life with a reliability of 95%. In the computation, it is assumed that fatigue life follows Weibull distribution. Two sets of faced samples and two sets of ground samples are tested for bending fatigue. The test is under constant amplitude in high cycle fatigue regime under room temperature. The results show that the safety ratios of face-turned samples are significantly smaller than are those of ground samples. Consequently, it is suggested that fatigue life variance be considered as a new process capability. This capability serves as a basis in choosing manufacturing processes for making fatigue critical products such as aircraft. Another finding is the positive correlation between the residual stress variation and fatigue life variation. This correlation suggests that a better understanding and prediction of residual stress lead to a better prediction of fatigue life.

scholarly journals ARTERIAL WALL MECHANICS AND CLINICAL IMPLICATIONS AFTER CORONARY STENTING: COMPARISONS OF THREE STENT DESIGNS

2012 ◽  
Vol 04 (02) ◽  
pp. 1250013 ◽  
Author(s):  
LINXIA GU ◽  
SHIJIA ZHAO ◽  
STACEY R. FROEMMING
Keyword(s):  
Stress Distributions ◽  
Cobalt Chromium ◽  
Stress Concentrations ◽  
Stent Deployment ◽  
Stress Variation ◽  
Stent Restenosis ◽  
Arterial Wall Mechanics ◽  
The Impact ◽  
The Relationship ◽  
In Stent Restenosis

The goal of this work is to quantitatively assess the relationship between the reported restenosis rates and stent induced arterial stress or strain parameters through finite element method. The impact of three stent designs (Palmaz–Schatz stent, Express stent, and Multilink Vision stent) on the arterial stress distributions were characterized. The influences of initial stent deployment location, stent-tissue friction, and plaque properties on the arterial stresses were also investigated. Higher arterial stresses were observed at the proximal end of the plaque. The Multilink–Vision stent induced lesser stress concentrations due to the high stiffness of the Cobalt Chromium material and thinner strut thickness. The stent-induced arterial stress concentrations were positively correlated with the reported in-stent restenosis rates, with a correlation coefficient of 0.992. Stent deployment initiated at the center of the lumen led to less arterial stress variation, while deployment closer to the thinner edge of the plaque causes higher arterial stresses. The friction between the stent and tissue was found to contribute to larger stress alternations for the plaque only. Increased plaque stiffness resulted in a reduced arterial stress concentration and clinical restenosis rate. Results presented herein suggested that arterial stresses serve as a comprehensive index factor to predict the occurrence of in-stent restenosis, which will facilitate the new stent design and surgical planning.

scholarly journals Numerical Simulation of Geostress and Support of Roadway Crossing Strata in Complex Stress Condition

2012 ◽  
Vol 446-449 ◽  
pp. 1781-1784
Author(s):  
Tong Xu Wang ◽  
Lai Yuan Li ◽  
Wen Hai Zheng ◽  
Yang Liu ◽  
Tao Hou ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mining Area ◽  
Complex Stress ◽  
Simulation Software ◽  
Stress Variation ◽  
Roof Structure ◽  
Rock Structure ◽  
Stability Classification ◽  
The Stability ◽  
The Impact

Affected by a group of underground chambers and gobs of working faces, the track sub-inclined shaft of 430 mining area in Geting coal mine, which crosses coal seam and faults repetitively, lies in high and complex stress environment. Based on geostress results measured in the field, FLAC3D numerical simulation software was used to simulate the regional geostress in the area near the roadway, referring to the impact of the gobs and chambers. And the stress variation law along the roadway was given at last. Then the roadway roof structure zone chart was drawn according to the detection results with the rock video detection recorder. Finally, stability of different sections of the roadway and the support advice corresponding to each section was gained. The results show that comprehensive consideration of geostress variation law and surrounding rock structure is necessary in the stability classification and the support of roadways. The research methods and ideas given in this paper is feasible.

The impact of sampling methods on evacuation model convergence and egress time

2019 ◽  
Vol 185 ◽  
pp. 24-34 ◽  
Author(s):  
Ruggiero Lovreglio ◽  
Michael Spearpoint ◽  
Mathilde Girault
Keyword(s):  
Sampling Methods ◽  
Evacuation Model ◽  
The Impact

scholarly journals A Stairs Evacuation Model Considering the Pedestrian Merging Flows

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xia Zhong Zheng ◽  
Dan Tian ◽  
Ming Zhang ◽  
Chaoran Hu ◽  
Liyang Tong
Keyword(s):  
Pedestrian Flow ◽  
Output Rate ◽  
Evacuation Time ◽  
Building Evacuation ◽  
Complex Interactions ◽  
Proposed Model ◽  
Three Stages ◽  
Evacuation Model ◽  
The Impact

Pedestrian merging flows are common in a stairs evacuation process, which involves complex interactions among pedestrians that substantially restrict the efficiency of the stairs evacuation process. Analyzing the pedestrian merging flows process and improving the efficiency of stairs evacuation are urgent and essential tasks. A novel simplified stairs evacuation model for simulating and analyzing the stairs evacuation process, which considers the impact of merging flows, is proposed in this process. The dynamic pedestrian output rate of a floor platform is calculated by the number of pedestrians on the floor platform. The merging ratio determined by the design size of stairs is adopted to determine the ratio between the stairs pedestrian flow and the floor pedestrian flow in the pedestrian output rate of the floor platform. To evaluate the stairs evacuation process is divided into three stages based on the pedestrian merging flows process, and the evacuation time at each stage is computed by the dynamic pedestrian output rate of the floor platform. The stairs evacuation capacity is calculated by the evacuation time and the number of pedestrians. A case study of a six-floor building evacuation is investigated, and the reliability and feasibility of the proposed model is verified. By establishing different merging ratios, the optimal merging ratio is obtained by comparing the evacuation capacities of different merging ratios, which provides a reference of stairs design for designers.

scholarly journals Stability and Resistance of Steel Continuous Beams with Thin-Walled Box Sections

2018 ◽  
Vol 64 (4) ◽  
pp. 123-143 ◽  
Author(s):  
K. Brzezińska ◽  
A. Szychowski
Keyword(s):  
Local Buckling ◽  
Effective Characteristics ◽  
Continuous Beam ◽  
Longitudinal Stress ◽  
Stress Variation ◽  
Continuous Beams ◽  
Thin Walled ◽  
Elastically Restrained ◽  
Ultimate Resistance ◽  
The Impact

AbstractThe issues of local stability and ultimate resistance of a continuous beam with thin-walled box section (Class 4) were reduced to the analysis of the local buckling of bilaterally elastically restrained internal plate of the compression flange at longitudinal stress variation. Critical stress of the local buckling was determined using the so-called Critical Plate Method (CPM). In the method, the effect of the elastic restraint of the component walls of the bar section and the effect of longitudinal stress variation that results from varying distribution of bending moments were taken into account. On that basis, appropriate effective characteristics of reliable sections were determined. Additionally, ultimate resistances of those sections were estimated. The impact of longitudinal stress variation and of the degree of elastic restraint of longitudinal edges on, respectively, the local buckling of compression flanges in the span section (p) and support section (s) was analysed. The influence of the span length of the continuous beam and of the relative plate slenderness of the compression flange on the critical ultimate resistance of box sections was examined.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

Sign in / Sign up

Export Citation Format

Share Document