Structural Response of Laminated Composite Glass Panel under the Influence of Different Load Combinations

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International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459,ISO 9001:2008 Certified Journal, Volume 4, Issue 11, November 2014)

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Structural Response of Laminated Composite Glass Panel

under the Influence of Different Load Combinations

Vichitra Venu

1

, Sony Syed

2

1

PG Student, 2Assistant Professor, KMEA Engineering College, Ernakulum, India

Abstract—There is a great increase in the application of

Laminate glass (LG) elements in modern and innovative Architectural Engineering. Glass elements are frequently used as structural components because of aesthetic, lighting, and architectural advantages. Laminated glass units used for glazing buildings consist of two thin glass plates bonded together by a thin core material, called Polyvinyl Butyral (PVB). The impact resistance of this laminated glass plate is higher than that of a single glass plate of same thickness in total. In this context, the paper focuses on the Structural response of Laminated Composite Glass panel subjected to dif erent load combinations and this Laminated Composite Glass panel also compared with Brick wall. Static, Modal, and Spectrum analysis are carried out for both Laminated Composite Glass panel and Brick Wall by using Finite Element Software ANSYS 14. Nonlinear buckling analyses the global glass panel behavior was studied analyzing glass panel deformations, stresses distribution and support reactions. The parametric study was carried out to identify the most important parameters, evaluating their influence on shear buckling behavior. The influence of the glass panel and connection device geometrical and material properties on critical shear force, global deformation, stress distribution and support reaction could be determined.

Keywords— Brick wall,Laminated composite glass panel,

Polyvinyl Butyral,Response spectrum, Von Mises stress

I. INTRODUCTION

The use of monolithic or laminate glass (LG) elements in modern and innovative architectural applications showed a strong increase in the last years. Because of aesthetic, lighting, and architectural advantages, glass elements are frequently used as structural components able to sustain loads. However, the real capabilities of such innovative bearing components are currently not well known and several aspects related to their typical load-carrying behaviour are very complex to evaluate. The load-carrying capacity of LG beams or panels, for example, strongly depends on the degradation of the mechanical properties of the interlayer, as well as on the presence and the amplitude of possible imperfections, or the presence of additional external loads.

The latest trends in contemporary architecture are fully transparent pavilions: a single storey building free of any steel or concrete frame, where glass panels are used as unique vertical structural elements to support the roof. In this application, individual glass panel is supported on two sides (roof and foundation) and subjected to in-plane shear force (lateral wind),out-of-plane distributed load (perpendicular wind) and in-plane compression force (self-weight of the roof, snow) and this laminated glass panel subjected to seismic load.

Laminated glass units used for glazing buildings consist of two thin glass plates bonded together by a thin core material, called Polyvinyl Butyral (PVB). The impact resistance of this laminated glass plate is higher than that of a single glass plate of same thickness in total. In this context, the paper focuses on the Structural response of Laminated Composite Glass panel subjected to different load combinations and this Laminated Composite Glass panel also compared with Brick wall. While several studies on glass plate behaviour under distributed load and column buckling exist, shear buckling of two sides supported glass panel has not been investigated yet. Therefore, research on this topic gives original and innovative importance to both theoretical (glass panel under shear loading) and practical (use of glass envelope for building stabilization) applications. Static, Modal, and Spectrum analysis are carried out both Laminated Composite Glass panel and Brick Wall by using Finite Element Software ANSYS 14. Nonlinear buckling analyses the global glass panel behaviour was studied analyzing glass panel deformations, stresses distribution and support reactions. The parametric study was carried out to identify the most important parameters, evaluating their influence on shear buckling behaviour. The influence of the glass panel and connection device geometrical and material properties on critical shear force, global deformation, stress distribution and support reaction could be determined.

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Advanced numerical models of point and linear supported glass panel were implemented using the Finite Element Code Ansys. Static, Modal and Spectrum analysis are carried out both Laminated Composite Glass panel and Brick Wall to determine the effect various load combination. The parametric study was carried out to identify the most important parameters, evaluating their influence on shear buckling behaviour. The influence of the glass panel and connection device geometrical/material properties on critical shear force, global deformation, stress distribution and support reaction could be determined. IS: 3548 - 1988 - Code of Practice for Glazing in Buildings, IS: 10439 - 1983 - Code of Practice for Patent Glazing and BS: 6262: Part 6: 1997 - Code of Practice for Glazing for Buildings: Special Applications are IS codes and standards used to model the glass panel.

II. PAGE LAYOUT

A. Modelling of Laminated composite Glass panel and Brick wall.

The numerical modelling consists of the following procedure Construction of the model, element types, material properties, meshing of the model, boundary conditions, load introductions and solution procedure. The modelling of laminated composite Glass panel is developed by using the Finite Element software ANSYS 14. It enables the prediction of global behaviour including pressure distribution, stress distribution and support reactions of a glass panel subjected to different load combination. The numerical model is divided into a finite number of elements satisfying the equilibrium and compatibility at each node and along the boundaries between the elements. Holes are constructed at the four corners with diameter of 50mm.Size of laminated glass panel is 2000mm by 3210mm and 20 mm thickness. The modeling consists of the following procedure Construction of the model, element types, material properties, meshing of the model, boundary conditions, load introductions and solution procedure. The modeling of laminated composite Glass panel with holes at the corners is developed by using the Finite Element software ANSYS 14.Element types used for modeling are SHELL 281 for Laminated Glass and SOLID 186 for Polyvinyl Butyral (Adhesive). SHELL281 is suitable for analyzing thin to moderately-thick shell structures.

[image:2.612.323.565.231.508.2]

The element has eight nodes with six degrees of freedom at each node translations in the x, y, and z axes, and rotations about the x, y, and z-axes and SOLID186 are a higher order 3-D 20-node structural solid element. SOLID186has quadratic displacement behavior and is well suited to modeling irregular meshes. The element is defined by 20 nodes having three degrees of freedom per node translations in the nodal x, y, and z directions.

Figure 1: Laminated composite Glass panel with holes

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Figure 2: Ordinary Brick wall

B. Effect of pressure on Laminated composite Glass panel and Brick wall

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Static analysis can be used to determine the effect of pressure in laminated composite glass panel and ordinary brick wall. Static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. Steady loading and response conditions are assumed that is, the loads and the structure's response are assumed to vary slowly with respect to time. A static structural analysis can be either linear or nonlinear. It includes applying boundary conditions, applying loads and solving the static analysis. Effect of pressure on laminated glass panel without holes and ordinary brick wall are shown below. When the glass plate and brick wall is subjected to pressure the maximum principle stresses and von mises stress occur at the long side and decrease when moving to the centre. Both laminated composite glass panel and brick wall has same effect due to effect of pressure.

Figure 3: Von mises stress of LG Panel

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198 C. Effect of pressure and wind load on laminated

composite

Glass panel and Brick wall

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Effect of pressure and snow load in laminated composite glass panel and brick wall can be determined by static analysis in Ansys. Static analysis can be used to determine the effect of pressure and wind load in laminated composite glass panel and ordinary brick wall. Static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. Steady loading and response conditions are assumed; that is, the loads and the structure's response are assumed to vary slowly with respect to time. Both laminated composite glass panel and brick wall has same effect due to effect of pressure and wind load. Principle stress is maximum at sides in laminated glass panel but in the case of brick wall maximum stress is occur at the centre of the wall. But in the case of Von Mises Stress maximum is stress occur at edges in both laminated composite glass panel and ordinary brick wall.

[image:4.612.48.288.387.657.2]

Figure 5: Von mises stress of LG Panel

Figure 6: Von Mises stress of Brick wall

D. Modal Analysis of Laminated composite Glass panel

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It can also serve as a starting point for another, more detailed, dynamic analysis, such as a transient dynamic analysis, a harmonic analysis, or a spectrum analysis. The natural frequencies and mode shapes are important parameters in the design of a structure for dynamic loading conditions. This technique is usually presented using parameters which are defined by complicated mathematical derivations Modes are inherent properties of a structure, and are determined by the material properties (mass, damping, and stiffness), and boundary conditions of the structure. Each mode is defined by a natural (modal or resonant) frequency, modal damping, and a mode shape (i.e. the so called modal parameters).

Figure 7: Fifth mode shape of LG panel

Resonances are determined by the material properties (mass, stiffness, and damping properties), and boundary conditions of the structure. Each mode is defined by a natural (modal or resonant) frequency, modal damping, and a mode shape. If either the material properties or the boundary conditions of a structure change, its modes will change. For in-stance, if mass is added to a vertical pump, it will vibrate differently because its modes have changed. At or near the natural frequency of a mode, the overall vibration shape (operating deflection shape) of a machine or structure will tend to be dominated by the mode shape of the resonance.

[image:5.612.49.290.290.546.2]

Modes are further characterized as either rigid body or flexible body modes. All structures can have up to six rigid body modes, three translational modes and three rotational modes. If the structure merely bounces on some soft springs, its motion approximates a rigid body mode.

Figure 8: Side view of fifth mode shape of LG panel

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Figure 9: Third mode shape of Brick wall

Figure 10: Side view of third mode shape of Brick wall

E. Effect of seismic load on laminated composite Glass panel (Spectrum analysis)

A spectrum analysis is one in which the results of a modal analysis are used with a known spectrum to calculate displacements and stresses in the model. It is mainly used in place of a time-history analysis to determine the response of structures to random or time-dependent loading conditions such as earth-quakes, ocean wave loads, jet engine thrust, rocket motor vibrations. In order to perform the seismic analysis and design of a structure to be built at a particular location, the actual time history record is required. However, it is not possible to have such records at each and every location. Further, the seismic analysis of structures cannot be carried out simply based on the peak value of the ground acceleration as the response of the Structure depends upon the frequency content of ground motion and its own dynamic properties. To overcome the above difficulties, earthquake response spectrum is the most popular tool in the seismic analysis of structures. There are computational advantages in using the response spectrum method of seismic analysis for prediction of displacements and member forces in structural systems. The method involves the calculation of only the maximum values of the displacements and member forces in each mode of vibration using smooth design spectra that are the average of several earthquake motions. The spectrum is a graph of spectral value versus frequency that captures the intensity and frequency content of time-history loads. Three types of spectra are available for a spectrum analysis they are Response Spectrum, Dynamic Design Analysis Method (DDAM) Power Spectral Density (PSD).

A response spectrum represents the response of single-DOF systems to a time-history loading function. It is a graph of response versus frequency, where the response might be displacement, velocity, acceleration, or force. Two types of response spectrum analysis are possible: single-point response spectrum and multi-point response spectrum. Response spectra are curves plotted between maximum response of SDOF system subjected to specified earthquake ground motion and its time period (or frequency). Response

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Figure 11: Graphical representation of seismic acceleration of LG panel (1st_mode)

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Figure 12: Graphical representation of seismic acceleration of LG panel (2nd_mode)

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Figure 13: First mode shape of LG panel

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202 F. Effect of seismic load on Ordinary Brick wall (Spectrum

analysis)

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Spectrum analysis is carried out to determine the mode shape and acceleration of brick wall .A spectrum analysis is one in which the results of a modal analysis are used with a known spectrum to calculate displacements and stresses in the model. It is mainly used in place of a time-history analysis to determine the response of structures to random or time-dependent loading conditions such as earthquakes, ocean wave loads, jet engine thrust, rocket motor vibrations. In order to perform the seismic analysis and design of a structure to be built at a particular location, the actual time history record is required.

[image:8.612.49.291.295.483.2]

Figure: 15 Graphical representation of seismic acceleration of Brick wall (1st_mode)

Figure 16: Graphical representation of seismic acceleration of Brick wall (2nd_mode)

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Figure 17: First mode shape of Brick wall

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III. CONCLUSIONS

This study considers the structural response of laminated composite glass panels subjected to different loading conditions and this laminated glass panel compared with ordinary brick wall. Static, Modal and Spectrum analysis are carried out for both Laminated Composite Glass panel and Brick Wall by using Finite Element Software ANSYS 14.

1. The structural response of laminated composite glass panels and ordinary Brick wall subjected to different loading conditions was carried out. 2. Due to the effect of pressure and wind load, both

laminated glass panel and ordinary brick wall can withstand the same effect.

3. Mode shapes analysis are also carried out for both laminated glass panel and brick wall.

4. In the case of seismic analysis (spectrum analysis) spectral acceleration is more in brick wall compared to laminated composite glass panel. So laminated composite glass panel is more suitable for seismic regions. So it can replace ordinary Brick wall. REFERENCES

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