Analysis of methods of determining the interlaminar shear strength of composite materials

1977 ◽  
Vol 12 (4) ◽  
pp. 573-580 ◽  
Author(s):  
I. G. Zhigun ◽  
V. A. Yakushin ◽  
Yu. N. Ivonin
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Interlaminar Shear Strength ◽  
Interlaminar Shear

The Edge Shear Test - An Alternative Testing Method for the Determination of the Interlaminar Shear Strength in Composite Materials

2015 ◽  
Vol 825-826 ◽  
pp. 806-813 ◽  
Author(s):  
Kay André Weidenmann ◽  
Lisa Baumgärtner ◽  
Benedikt Haspel
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Shear Test ◽  
Shear Failure ◽  
Interlaminar Shear Strength ◽  
Shear Load ◽  
Testing Method ◽  
Shear Loads ◽  
Interlaminar Shear

The interlaminar shear strength is a characteristic value describing the mechanical behavior of composite materials such as laminates. Several methods for the determination of the interlaminar shear strength are described in open literature by several authors. Among these methods, the ILSS test (DIN EN ISO 14130) measuring the apparent interlaminar shear strength by using a modified bending test is the state of the art technique, as both the necessary testing equipment and the sample geometry are quite common. However, the ILSS tests implements shear loads indirectly by bending often leading to sample failure which is then not solely initiated by shear loads. Particularly for ductile matrices or those showing pronounced elastic behavior under bending, no interlaminar shear failure can be implemented and the interlaminar shear strength can not been determined or – if the user is not sensitized to the identification of non-shear failure behavior – the determined value is not correct.Up to now, alternative methods for determining the interlaminar shear strength implementing a shear load directly to the sample are quite elaborate regarding the test equipment to be used or the specimen preparation and geometry. In this contribution the authors present a novel test setup for an edge shear test which allows both a direct shear load and at the same time a reduced complexity of the specimen geometry which is comparable to those used in the ILSS test. The authors present results based on this novel testing method in comparison to conventional ILSS tests.

Ultrasound Characterization of IM7/PEEK Composite Materials

2014 ◽  
Author(s):  
Jikai Du ◽  
Katrina M. Ladd ◽  
Fereidoon Delfanian
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Flow Rate ◽  
Ultrasound Velocity ◽  
Processing Parameters ◽  
Interlaminar Shear Strength ◽  
Fiber Direction ◽  
Peek Composite ◽  
Interlaminar Shear ◽  
N2 Flow Rate

IM7/PEEK composite materials may experience large mechanical and thermal stresses during service, and their failure mechanisms can be complex and have various modes. In this study, IM7/PEEK specimens for interlaminar shear strength testing were evaluated by both nondestructive ultrasound method and standard destructive test. First, IM7/PEEK specimens were fabricated under various processing parameters including roller speed, torch temperature, roller temperature, compaction level, N2 flow rate, and material tension level. Then ultrasound longitudinal wave velocity that is normal to fiber direction was evaluated and the influence of measuring locations and ultrasound frequencies from 0.5 MHz to 10.0 MHz were studied. Experimental results showed that 5.0 MHz is the most sensitive frequency to fabrication conditions and that ultrasound velocity can be related to some processing parameters such as materials tension, N2 flow rate and temperature. Finally, interlaminar shear strength experiments were carried out by standard short beam bending destructive tests. The relationship between ultrasound velocity and standard destructive tests were analyzed and the potential of ultrasound velocity for interlaminar shear strength evaluation was discussed.

Mechanical properties of multiwall carbon nanotubes/unidirectional carbon fiber-reinforced epoxy hybrid nanocomposites in transverse and longitudinal fiber directions

2021 ◽  
pp. 096739112098651
Author(s):  
Saeedeh Saadatyar ◽  
Mohammad Hosain Beheshty ◽  
Razi Sahraeian
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Epoxy Resin ◽  
Interlaminar Shear Strength ◽  
Lap Shear Strength ◽  
Transverse Tensile ◽  
Lap Shear ◽  
Longitudinal Fiber ◽  
Interlaminar Shear ◽  
Multiwall Carbon

Unidirectional carbon fiber-reinforced epoxy (UCFRE) is suffering from weak transverse mechanical properties and through-thickness properties. The effect of different amount (0.1, 0.3 and 0.5 phr which is proportional to 0.09, 0.27 and 0.46 wt%, respectively) of multiwall carbon nanotube (MWCNT), on transverse tensile properties, flexural strength, fracture toughness in transverse and longitudinal fiber directions, interlaminar shear strength and lap shear strength of UCFRE has been investigated. Dicyandiamide was used as a thermal curing agent of epoxy resin. MWCNT was dispersed in the epoxy resin by ultrasonic instrument and their dispersion state was investigated by scanning electron microscopy (SEM). The curing behavior of epoxy resin and its nanocomposites was assessed by differential scanning calorimetry. Results show that transverse tensile strength, modulus and strain-at-break were increased by 28.5%, 25% and 14%, respectively by adding 0.1 phr of MWCNT. Longitudinal flexural properties of UCFRE was not changed by adding different amount of MWCNT. Although longitudinal flexural strength was increased by 5% by adding 0.1 phr of MWCNT. Fracture toughness in transverse and longitudinal fiber directions was increased by 39% and 9%, respectively at 0.3 phr of MWCNT. Results also show that interlaminar shear strength and lap shear strength were increased at 0.3 phr of MWCNT by 8% and 5%, respectively. These increases in mechanical properties were due to the good adhesion of fibers to the matrix, interlocking and toughening action of MWCNT as revealed by SEM.

Effect of consolidation force on interlaminar shear strength of CF/PEEK laminates manufactured by laser-assisted forming

2021 ◽  
Vol 266 ◽  
pp. 113779
Author(s):  
Qiuyu Miao ◽  
Zhihong Dai ◽  
Guangyi Ma ◽  
Fangyong Niu ◽  
Dongjiang Wu
Keyword(s):  
Shear Strength ◽  
Interlaminar Shear Strength ◽  
Interlaminar Shear

Surface and Composite Interface of Carbon Fiber Modified by Grafting of Diethanolamine

2009 ◽  
Vol 79-82 ◽  
pp. 497-500 ◽  
Author(s):  
Lei Chen ◽  
Zhi Wei Xu ◽  
Jia Lu Li ◽  
Xiao Qing Wu ◽  
Li Chen
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Functional Groups ◽  
Carbon Fibers ◽  
Irradiation Dose ◽  
Interlaminar Shear Strength ◽  
Epoxy Composites ◽  
Composite Interface ◽  
Γ Ray ◽  
Interlaminar Shear

The γ-ray co-irradiation method was employed to study the effect of diethanolamine modification on the surface of carbon fiber (CF) and the interfacial properties of CF/epoxy composites. Compared with the original carbon fiber, the surface of modified fibers became rougher. The amount of oxygen-containing functional groups was increased and the nitrogen element was detected after irradiation grafting. The interlaminar shear strength (ILSS) of composites reinforced by carbon fibers irradiated in diethanolamine solution was increased and then decreased as the irradiation dose increased. The ILSS of CF/epoxy composites was enhanced by 16.1% at 200kGy dose, compared with that of untreated one. The γ-ray irradiation grafting is expected to be a promising method for the industrialized modification of carbon fibers.

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