effect of heat on bending behavior of composite...

IPASJ International Journal of Mechanical Engineering (IIJME) Web Site: http://www.ipasj.org/IIJME/IIJME.htm

A Publisher for Research Motivation........ Email: [email protected] Volume 4, Issue 3, March 2016 ISSN 2321-6441

Volume 4, Issue 3, March 2016 Page 44

ABSTRACT This research was carried out to study the effect of heat on bending behavior of composite material with three types of composite beam (simply supported beam, fixed and cantilever beam). Multi-layer samples of glass fiber-polyester composite with 0/ 90 and 45 /-45 orientation were tested. The experimental results showed that increasing the temperature has an effect on the deflection at the same load; also the change in the orientation of lamination of the fiber glass has an effect on the deflection values. Moreover, the results showed that the specimens with the 0/ 90 have a deflection less than the orientation (45/-45). On the other hand, assessment of these results is carried out analytically by using (ANOVA analysis). Keywords: Composite materials, bending behavior, Regression analysis, ANOVA.

1. INTRODUCTION In spite of using composite materials from the past, but today, they become so necessary because they are considered important subject in the industrial application and engineering according to what they Have of the high mechanic properties so this material made an important industrial improve which entered the area of the industry in the form that equals to other material like the metal and its casts [1]. The composite material behavior under different temperature is an important parameter to be considered because it can in many cases, determine the upper bound on the temperatures at which a material has suitable properties [2]. Duan B., et.al. [3] presented a finite element method for predicting critical temperature and post buckling deflection (large thermal deflection) for composite plates embedded with restrained shape memory alloy (SMA) wires and subjected to high temperature. The temperature dependent material properties of SMA and matrix and the geometrical nonlinearities of large deflection were considered in the formulation. Also, an incremental method consisting of small temperature increments and including the effect of initial deflection and initial stresses for material nonlinearities was presented. Within each temperature increment, the Newton – Raphson iteration was used calculation large thermal deflection, the result showed that the critical buckling temperature can be raised high enough and the post buckling deflection can be reduced and controlled for a given operation temperature range by the proper selection of SMA volume fraction. S. Maensiri [4] studied the thermal shock behavior of sintered alumina and alumina/SiC Nano composites. The thermal shock testing was carried out by means of quenching into water from high temperatures (T in the range 0–750 °C). Both Single shocks and repeated shocks were used. The damage introduced by thermal shock was characterized by degradation of strength in four-point bending and by changes in Young’s modulus. The Effects of the surface finish of the test specimens (either ground or highly polished surfaces) on the thermal shock resistance were also studied. In both alumina and Nano composite materials, specimens with ground surfaces showed a better resistance to thermal shocks than specimens with polished surfaces. Pascalis et.al. [5] studied laminated fiber-reinforced composite stiffened plate with [0/90/±45]s plies made of S-Glass/epoxy are evaluated via computational simulation to damage and fracture progression. The loads are pressure and temperature which varies from 21 to 65.5 °C (case I) and from 143.3 to 21 °C (case II). An integrated computer code is used for the simulation of the damage progression.

Results show that damage initiation begins at low load level, with matrix cracking at the 0° (bottom and top) plies, fiber Fracture at the bottom (0°) ply and interplay delaminating at the top (0°) ply. Increasing the applied pressure, the damage growth is expended resulting in fracture through the thickness of the structure. Camelia and Horiatis [6] described the aspects concerning methodology of recycling of (compact disks), to develop a new composite material made of a polyester resin reinforced with chopped material. It is known that polycarbonates are mainly used to manufacture of, while a very thin aluminum layer is additionally used to record information. The first of all, the hand lay-up technology is used to prepare a board made of the composite material involved. Then, the composite specimens were cut from the board and subjected to the flexural test (three point's method). Azzam A. et.al. [7] studied the

Effect of Heat on Bending Behavior of Composite Material

Dr. Muna S. Kassim 1, Dr. Sajeda Kareem Radhi 2, Ammar Fadhil Hussein Al-Maliki 3

1,2,3 Assistant Professor, Al- Mustansiriyah university, Mechanical engineering department




response of composite laminate structure to three-point bending load was investigated by subjecting two types of stacking sequences of composite laminate structure by using electronic universal tester (Type: WDW-20) machine. Optical microscope was selected in order to characterize bending damage, delamination, and damage shapes in composite laminate structures. The results showed that the [0/90/-45/45]2s exhibits a brittle behavior, while other laminates exhibit a progressive failure mode consisting of fiber failure, debonding (splitting), and delamination. The [45/45/90/0]2s laminate has a highly nonlinear load–displacement curve due to compressive yielding.

2. EXPERIMENTAL WORK 2.1. Specimen preparation

In this study, E-glass (E refer to electrical due to its superior isolative properties) is used as it give us good mechanical properties with polyester (resin matrix). The type of E-glass fiber used in work as reinforced material is shown in the figure (1) below, which is continuous glass-fibers and used in two deferent orientations: 1. (0/90) Cross-ply laminate orientation. Figure (2) 2. (45/-45) Angle-ply laminates orientation. Figure (3)

Figure (1): Glass-fiber

Figure (2): Cross-ply laminates Figure (3): Angle-ply laminates

After the selection of raw materials, the molding operation starts. The mold used in preparing the specimens is from wood frame and glass with some needles as shown in figure (4).

Figure (4): The mold




The fibers are laid in the mold in the desired orientation figure (5), which is followed by the pouring and brushing processes.

Figure (5): Pouring and brushing

The mold is then closed by its cover, pressed and waiting of (24) hours thus, the composite material sheet is obtained. Then sheet is visually inspected and cut by a cutter machine to the specific specimen’s dimension according to the ISO standers for flexural test [8]. Final shape of specimen is shown in figure (6).

Figure (6): Final shape of test specimens

2.2. The Bending Test Apparatus

The bending test process is contained basically design and built a bending test device with an oven for study the effect of different supports for bending on composite material. In this study the apparatus consist of three main parts as follows:

1. The base block of the rig. 2. The fixture part: The fixtures are used to hold the specimens in the device for holding the weights (cantilever &

Fixed beams), and to carry the specimens as in simply supported beam from the two ends. 3. The dial gage: Its use in order to read the deflection of the specimens when the load is applied. 4. The oven: In this study the experiments done in a several temperatures so the oven is needed to make the spacemen

reach the desired temperature. 5. The hook: The hook that carry the loads as made in the workshop by forging the cast iron rod and bent it as shown

in figure above, to hang the loads on it.

The following figure illustrates the bending test apparatus:

Figure (7): The bending test apparatus



Volume 4, Issue 3, March 2016 7

The readings have taken after (5 – 15) min when the load is applied to reach as much a steady state of the deflection to take good readings and compare between them and plot the relation between the loads applied and the deflection that occurs in the beam.

3. RESULTS AND DISCUSSION The bending results presented in this chapter are divided (according to the reinforcement kind) into two groups. The first group including the results of the unidirectional multi-layer lamination specimen oriented with 0/90, while the second group including the results of the unidirectional multi-layer lamination specimen oriented with 45/-45 . The results of load and deflection (δ) of simply supported beam at three different values of temperature for the composite specimen oriented with (45/-45) and (0/90) directions and the number of layers are (8 layers) are shown in tables (1) and (2) respectively.

Load(N)

at T=27 °C

at T=60 °C

at T=90 °C

0 00.00 00.00 00.00 20 08.45 10.30 14.60 25 09.80 13.70 18.30 30 12.40 16.80 21.20 35 13.50 19.40 25.40 40 15.60 22.20 ----- 45 18.00 24.90 -----

Figures (8) and (9) present the variation of the load with deflection (δ) for the simply supported Beam the composite specimen oriented with (45/-45) and (0/90) directions. It can be notice that the deflection of the beam are increased with temperature and the maximum deflection is occurs at 90 C.

The results of the load and deflection of fixed beam at three different values of temperature for the composite specimen oriented with (45/-45) and (0/90) directions are shown in tables (3) and (4).

Load (N)

at T=27 °C

at T=60 °C

at T=90 °C

0 00.00 00.00 00.00 20 05.80 06.50 08.44 25 07.20 08.10 11.32 30 08.70 09.81 14.84 35 10.35 11.20 17.42 40 11.40 13.40 20.50 45 12.70 14.80 22.89 50 13.80 16.12 25.11 60 15.40 18.50 - 70 17.90 20.67 -

Table (1): Simply supported Beam the composite specimen oriented with (45/-45)

direction

Table (1): Simply supported Beam the composite specimen oriented with (45/-45)

direction

Figure (8): Simply supported beam the composite specimen oriented with (45 /-45) direction

Figure (9): Simply supported beam the composite specimen oriented with (0 /90) direction.




It can notice from the behavior of fixed beam is same as the simply supported beam. Also, it was observed that the values of deflection for fixed beam are less than that of simply supported beam. For cantilever beam the tables (5) and (6) are showing the results of load and deflection, but the values had been taken just at 27 C because of the size of the oven that could be broken because of the high loads on the beam.

Table (5): Cantilever Beam the composite specimen oriented with (45/-45) direction

Table (6): Cantilever Beam the composite specimen oriented with (0/90) direction

Load (N)

at T=27°C

at T=60 °C

T=90 °C

0 00.00 00.00 00.00 20 04.55 05.60 08.40 25 05.55 06.90 10.20 30 06.25 08.10 13.50 35 06.80 09.50 15.80 40 07.74 10.90 17.20 45 08.70 12.60 18.90 50 09.65 13.20 20.10 60 10.70 16.30 22.40 70 11.90 18.50 24.60

Load (N)

at T=27 °C

at T=60 °C

at T=90 °C

0 00.00 00.00 00.00 20 03.80 04.60 08.50 25 04.75 06.32 10.33 30 06.10 07.53 13.12 35 06.80 08.80 15.50 40 07.95 10.12 18.10 45 09.40 11.75 20.54 50 10.70 13.91 23.80 60 11.50 15.70 - 70 12.59 17.22 -

Load(N) at T=27 °C 0 00.00

20 09.20 25 11.40 30 14.80 35 17.10 40 20.20 45 24.80

Load(N) at T=27 °C 0 00.00

20 07.24 25 09.80 30 11.35 35 13.12 40 15.50 45 17.11 50 18.90 60 20.34 70 22.21

Table (3): Fixed Beam the composite specimen oriented with (45/-45) direction

Table (4): Fixed Beam the composite specimen oriented with (0/90) direction




The variation of the load with deflection for the cantilever beam of the composite specimen oriented with (45/-45) and (0/90) directions are shown in figures (10) and (11).

It can be seen that the deflection for the cantilever beam with the orientation (45/-45) higher than the deflection at the orientation (0/90). Figures (12, 13 and 14) present the variation of the deflection with the time for simply supported, fixed and cantilever beam at a particular load (45 Kg) and (27 °C).

These figures show that the deflection in the Cantilever Beam increase with time more than the simply supported beam and the Fixed Beam.

Figure (10): Cantilever Beam the composite specimen oriented with (45/-45) direction

Figure (11): Cantilever Beam the composite specimen oriented with (0 /90) direction

Figure (12): Fixed beam at 45 kg and 27 °C Figure (13): Simply supported beam at 45 kg and 27 °C temperature

Figure (14): Cantilever beam at 45 kg and 27 °C temperature




Composite materials used in this work are highly orthotropic because of the lengthwise arrangement of the long fibers. As shown in the figures for the unidirectional multi-layer fiber-reinforcement composite beam oriented with 0/90 and 45/-45 respectively, the behavior of the composite beam for the three types of the beams under the bending test. A small increase in deflection of the beam when the temperature is increasing because of the increase of the ductility of the specimens so that makes the deflection increase too.

Based on the results obtained from this study, it can be concluded that the unidirectional composite beam oriented with 0/90 can withstand higher bending loads compared with the orientation (45/-45).

The little change in deflection with load at higher number of layers indicates that for application of composite materials with high sensitivity to deflection, maximum number of layers should be used.

3. ANALYTICAL ASSESMENT OF RESULTS The results for all groups of tested materials were assessed using analysis of variance (ANOVA). ANOVA is approach of apportioning of an output of various inputs. The multiple linear regression models were obtained by using (Spss statistics 17.0) software, the regression equations formulated for three types of beams are:

Regression Analysis: Load(N) versus δ(mm) for simply supported beam with orientation (45°,-45°) at T=27 °C, 60 °C and 90°C respectively :

Load(N) = 1.66 + 2.30 δ(mm) T=27 ℃ (1)

Load(N) = 0.482 + 1.79 δ(mm) T=60 ℃ (2)

Load(N) = - 0.069 + 1.39 δ(mm) T=90 ℃ (3)

Regression Analysis: Load(N) versus δ(mm) for simply supported beam with orientation (0°,90°) at T=27 °C, 60 °C and 90°C respectively :

Load(N) = - 2.77 + 3.90 δ(mm) T=27 ℃ (4)

Load(N) = - 1.76 + 3.30 δ(mm) T=60 ℃ (5)

Load(N) = 1.84 + 1.91 δ(mm) T=90 ℃ (6)

Regression Analysis: Load(N) versus δ(mm) for fixed beam with orientation (45°,-45°) at T=27 °C, 60 °C and 90°C respectively :

Load(N) = - 4.70 + 5.87 δ(mm) T=27 ℃ (7)

Load(N) = - 0.688 + 3.76 δ(mm) T=60 ℃ (8)

Load(N) = - 3.56 + 2.72 δ(mm) T=90 ℃ (9)

Regression Analysis: Load(N) versus δ(mm) for fixed beam with orientation (0°,90°) at T=27 °C, 60 °C and 90°C respectively :

Load(N) = - 0.64 + 5.18 δ(mm) T=27 ℃ (10)

Load(N) = 0.80 + 3.82 δ(mm) T=60 ℃ (11)

Load(N) = 1.71 + 2.10 δ(mm) T=90 ℃ (12)

Regression Analysis: Load(N) versus δ(mm) for cantilever beam with orientation (45°,-45°) at T=27 °C is:

Load(N) = 2.24 + 1.84 δ(mm) T=27 ℃ (13)

Regression Analysis: Load(N) versus δ(mm) for cantilever beam with orientation (0°,90°) at T=27 °C is:

Load(N) = - 2.82 + 2.97 δ(mm) T=27 ℃ (14)




For example, the theoretical results were obtained by using ANOVA analysis for simply supported beam with orientation (45°,-45°) at T=27 °C, 60 °C and 90°C are shown in the table (7).

Table (7): Theoretical results for simply supported beam with (45/-45) direction

Load(N)

at T=27 °C

at T=60 °C

at T=90 °C

20 07.97 10.90 14.43 25 10.14 13.69 18.03 30 12.32 16.49 21.63 35 14.49 19.28 25.22 40 16.66 22.07 ----- 45 18.84 24.87 -----

Figures (15, 16 and 17) show a comparison between theoretical results using ANOVA analysis and experimental results for simply supported beam with orientation (45°,-45°) at T=27 °C, 60 °C and 90°C respectively.

As shown in this comparison, there is a reasonable matching between experimental and theoretical results.

The regression analysis: δ(mm) versus time(sec) for three types of beams at 45 kg load and T=27 ℃ can be obtained from the following equations:

- For simply supported beam:

Figure (15): Experimental and theoretical load-deflection curve for simply supported beam with

(45,-45) at T=27 ℃

Figure (16): Experimental and theoretical load-deflection curve for simply supported beam with

(45,-45) at T=60 ℃

Figure (17): Experimental and theoretical load-deflection curve for simply supported beam with (45,-45) at T=90 ℃




δ(mm) T=27 ℃ at 45 kg =15.6 + 0.121 Time(sec) (15)

- For fixed beam:

δ(mm)T=27℃ at 45 kg =7.80 + 0.0407 Time(sec) (16)

- For cantilever beam:

δ(mm) T=27℃ at 45 kg =16.2 + 0.164 Time(sec) (17)

4. CONCLUSIONS Based on the results obtained from this study for multi-layer composite beams under bending test for the three types of beams, it can be concluded: 1. The composite material with unidirectional orientation of 0/90 better than the other orientations. 2. Heating the specimens increases the maximum deflection of the beam in the same load applied. 3. Maximum deflection is in the cantilever beam. 4. The deflection of the fixed beams is the lowest when compared with the two other beams, and the simply supported

beam is lower than the cantilever at the same load and temperature. 5. Depending on the results that have been obtained from the analytical method (ANOVA analysis), there is a

reasonable match between the experimental and theoretical results. REFERENCES [1] JP Agrawal, “Composite materials,” Hand book, Explosives research and development laboratory pune, 1990. [2] João Marciano Laredo dos Reis, “Effect of Temperature on the Mechanical Properties of Polymer Mortars,”

Journal of Materials Research, vol.(15), No.(4), pp. (645-649), 2012. [3] Bin Duan, Mohammed Tawfik, Sylvain, N. Goek, Jeng – Jong Ro and Chuh Mei, “Analysis and Control of Large

Thermal Deflection of Composite Plates Using Shape Memory Alloy,” Industrial and Commercial Applications of Smart Structures Technologies, E-mail: [email protected], 2000.

[4] S. Maensiri S. G.roberts, “Thermal Shock of Ground and Polished Alumina and Al2O3/SiC Nano composites,” JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, DECEMBER, 2002.

[5] Pascalis K. Gotsis, Christos C. Chamis, Kostantinos David and Frank Abdi, “Progressive Fracture of Laminated Composite Stiffened Plate,” NASA/TM-214927, August, 2007.

[6] Camelia CERBU, Horatiu TEODORESCU-DRAGHICESCU, “Bending Behaviour of the Composite Materials Made by Recycling of the CDs and DVDs,” Proceedings of the World Congress on Engineering, Vol. II, London, U.K., 2009.

[7] Azzam A and Li W, “An experimental investigation on the three-point bending behavior of composite laminate,” Global Conference on Polymer and Composite Materials, 2014.

[8] Handbook; “Plastics,” (Terminology, Sampling and Properties), 21 (1984), Vol.1, ISO 178-(1975), (E).

effect of heat on bending behavior of composite...

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