Computational Structural Design and Finite Element Analysis of Fire Cracker Safety Rooms

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Computational Structural Design and Finite Element Analysis of Fire Cracker Safety Rooms

K. Praveen,

ME (struct),

Star Lion College of engineering & Technology, Thanjore.

Abstract Many studies reveals that the improper structural design of fire cracker safety room which leads to increase in loss of life. Hence we took our study to explore a new design of safety room to withstand such a high pressure and also to study the exploded material movement during the explosion with respect to wall thickness, shape of the room, roof design. Here in explosion of the room the three major parameter took a vital they are wall thickness, shape of the room, roof design, where these parameter holds varying values which should be studied and evaluated inorder to achieve an ideal design of the safety room. Hence three values of each parameter have been taken to achieve the level of accuracy. By using taguchie technique we are getting twenty seven combinations of these parameters, which can be find out using MINITAB software. For this twenty seven combination we are designing the 3D model of the room using the software PRO-E. For evaluating these model we are importing the model to finite element software ANSYS, where the exploding pressure is given with respect to the constrains. From the stress and deformation results obtained from the ANSYS software we are evaluating the exact parameter for which the design is ideal. For the final evaluation of the results we are again using the MINITAB software, in which SN ration and MEAN values graphs are plotted to explore the exact value of the parameters for ideal safety room design.

Keywords ANSYS,Firework industries,shape of room,wall thickness,roof design

I.INTRODUCTION

Fireworks industries are mostly prone to fire and explosion. Hazardous chemicals are being used to produce light and radiant effects during the display of the firework crackers. It is reported that, accidents in fireworks industries lead to loss of human lives.The main objective of this research work is to focus on control methods on effects of fireworks explosion accidents. In general, fireworks accidents cant be avoided but accidents can be controlled by such control methods.Sivakasi supplies firecrackers and sparkers for all important ceremonies. For the colour effect of fireworks, toxic heavy metals like barium, aluminum, lead, mercury salts, antimony, copper, and strontium can be used in firework compositions. The smoke from fireworks consists mainly of fine toxic dusts that can easily enter the lungs. They are more harmful to the society as they pollute our environment which affects the infants, children, pregnant women, patients and senior citizens.

  1. LITERATURE REVIEW

    Bruce Ellingwood, E.V. Leyendecker and James T.P. Yao (1983) illustrated the need of incorporating the effects of abnormal loads in codes and standards for the design of structures. Abnormal loads, which usually are not considered in structural design because of their low probability of occurrence, may initiate a catastrophic failure if they occur. A case study shows that the probability of structural failure due to a gas explosion in a residential compartment may exceed probabilities associated with unfavourable combinations of ordinary design loads. Therefore, specific provision is needed in design standards to mitigate the effects.

    Christopher D. Eamon, James T. Baylot, and James L. ODaniel (2004) analysed concrete masonry unit walls subjected to blast pressure with the finite element method, to develop a computationally efficient and accurate model. Concrete masonry unit walls subjected to blast pressure were analyzed with the finite element method, with the goal of developing a computationally efficient and accurate model. Wall behaviour can be grouped into three modes of failure, which correspond to three ranges of blast pressures. Computational results were compared to high-speed video images and debris velocities obtained from experimental data. A parametric analysis was conducted to determine the sensitivity of computed results to critical modelling values. It was found that the model has the ability to replicate experimental results with good agreement. However, it was also found that, without knowledge of actual material properties of the specific wall to be modelled.

  2. SCOPE AND OBJECTIVES

    Analytical studies were conducted with help of ANSYS software to study the Static and Dynamic analysis of fireworks industrial buildings under impulsive loading.Totally 27 models were studied with various geometrical configurations in plan (9 models each for square, rectangular and hexagonal configuration). For all these three geometrical configurations, the plan area was kept equivalent to the plan area of the conventional unit, that is 10.8m2 (3.6 x 3 =10.8m2). The equivalent room dimension required for a square shape room for manufacturing shed of firework industry is 3.3m x 3.3m. ANSYS studies were conducted on 3.3m x 3.3m square model to suit the area of industrial unit as 10.8m2. The explosive loading of 600kN/m2 was considered

    Material properties

    Parameter

    Brick Masonry

    RCC

    L x B

    3.60m x 3.0m

    Density

    1900kg/m3

    2400kg/m3

    Youngs

    Modulus

    1.2 x104

    N/mm2

    2.3 x104

    N/mm2

    Loading parameter

    Parameter

    Maximum value

    Unit

    Static pressure Pso in bars

    25.163

    Bars

    Shock pulse duration tb in milliseconds

    0.450

    Millisecond

    Time of drag td in milliseconds

    0.630

    Millisecond

    Equivalent Pressure

    6.75

    Bars

    Equivalent Impulse

    320.625

    Ps (N msec /m2)

    Time Period

    0.303

    Seconds

    Peak ground

    Acceleration

    587

    G

    Note: 1 bar = 100kN/m2

    Static and Dynamic impulsive load of 600kN/m2 was applied on all the walls as uniform pressure acting on the walls. Finite element studies were conducted on brick masonry model of wall thickness 115mm,150mm,230mm.RCC roofing of 100mm thickness were taken into account various shapes such as flat, sloped and curved were considered in this study. The deflection behaviour of model structures was studied using ANSYS (version 12) software.

    OBJECTIVES

    • Identification of Risks in fireworks Industries.

    • Performing modelling structure for Fireworks industries.

    • Analysing the modelling structure by

    1. Static analysis

    2. Dynamic analysis

  3. METHODOLOGY

    ANSYS MINITABB

    Factors/parameters name

    Level 1

    Level 2

    Level 3

    WALL

    THICKNESS(mm)

    115mm

    150mm

    230mm

    SHAPE OF THE

    ROOM

    SQUARE

    RECTANGLE

    HEXAGONAL

    ROOF DESIGN

    FLAT

    TAPERED

    CURVED

    TAGUCHI FACTORS PRECEDENCE

  4. RESULTS AND DISCUSSIONS

    115- Square Curved

    The Stress on walls by static analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the entire walls in all direction.Static loading is considered.

    Static

    The Equivalent stress on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the side walls in bottom direction.Static loading is considered

    Static

    115-Square-Tapered

    The Total deformation on walls by static analysis.minimum stress value can be obtained at all ends.maximum stress value is obtained on the entire walls in all direction.static loading is considered

    The Stress on walls by static analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the entire walls in all direction.Static loading is considered.

    Dynamic

    The Total Deformation on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the all direction.Dynamic loading is considered.

    The Total deformation on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the side walls in bottom direction.Static loading is considered

    Dynamic

    The Total Deformation on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the all direction.Dynamic loading is considered.

    The stress on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the bottom direction.Dynamic loading is considered.

    230-Hexagonal-Flat

    Static

    The Stress on walls by static analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the entire walls in all direction.Static loading is considered.

    The Total deformation on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the side walls in bottom direction.Static loading is considered

    Dynamic

    The stress on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the all direction.Dynamic loading is considered.

    The Total Deformation on walls by dynamic analysis.Minimum stress value can be obtained at all ends.Maximum stress value is obtained on the bottom direction.Dynamic loading is considered.

  5. CONCLUSION

Finite element studies were conducted on brick masonry model of wall thickness 115mm,150mm,230mm. RCC roofing of 100mm thickness were taken into account various shapes such as flat, sloped and curved were considered in this study. The deflection behaviour of model structures was studied using ANSYS (version 12) software.The deflection behaviour of brick masonry under pyrotechnic explosive loading is studied in both static and dynamic analysis.In Taguchi method Main effects graph and interaction graph is plotted using MINITAB-15, statistical software from the main effects plot seen that slopes of line is reducing in the order Wall thickness,Roof Design,shape of the building.The models of 27 combinations were developed and tested.From the final results of stress and deformation value, three combinations 115mm square tapered, 115m square curved, 230mm hexagonal flat was considered as safe building structure.

REFERENCES

  1. Industrial Profile, Virudhunagar District, Government of Tamilnadu,: www.virudhunagar.tn.nic.in [accessed 28/8/2011].

  2. Fireworks. History of fireworks in Sivakasi.Obtained through the Internet: http://Sivakasionline.com/fireworks.php, [accessed 28/8/2011].

  3. The Explosives Act, 1884. Professional Book Publishers, New Delhi, 2007.

  4. The Explosives Rules, The Gazette of India: Extraordinary [part II sec. 3(i)] pp. 306 308, Controller of Publications, Delhi-110054. 29th December, 2008.

  5. Bruce Ellingwood, E. V. Leyendecker, and James T. P. Yao, (1983), Probability of failure from abnormal load, Journal of Structural Engineering at ASCE, Vol. 109, pp. 875-890.

  6. Christopher D. Eamon, James T. Baylot, and James L. ODaniel, (2004), Modeling concrete masonry walls subjected to explosive loads, Journal of Engineering Mechanics at ASCE, September issue, pp. 1098-1106

  7. Pedro F. Silva, Binggeng. Lu and Antonio Nanni, (2005), Prediction of blast loads based on the expected damage level by using displacement based method, Safety and Security Engineering Transaction:The Built Environment volume 82, pp.531-540.

  8. Ronald L. Shope, (2006), Response of wide flange steel columns subjected to constant axial load and lateral blast load, Civil Engineering Department, Blacksburg, Virginia.

  9. Pandey. A.K. et al., (2006), Non-linear response of reinforced concrete containment structure under blast loading, Nuclear Engineering and design 236, pp. 993-1002

  10. Jun-xiang XU and Xi-la LIU, (2008), Analysis of structural response under blast loads using the coupled SPH-FEM approach, Journal of Zhejiang University Science A, Vol. 9(9), pp. 1184-1192.

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