scholarly journals KARAKTERSTIK SERAPAN SUARA KOMPOSIT POLYESTER BERPENGUAT SERAT TAPIS KELAPA

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
I Made Astika ◽  
I Gusti Komang Dwijana
Keyword(s):  
Absorption Coefficient ◽  
Fiber Length ◽  
Sound Absorption ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Sound Absorption Coefficient ◽  
Fiber Volume ◽  
Absorption Frequency ◽  
Class D

The purpose of this study is to investigate of sound absorption of coconut filter fiber composites. The research material made with coconut filter fiber as reinforcement and matrix resin unsaturated polyester (UPRs) type Yukalac BQTN 157 with 1% hardener types MEKPO (Methyl Ethyl Ketone Peroxide) and fiber treatment by  0,5% KMnO4. Production methods is poltrusion and the variations of fiber volume fraction are 20, 25 and 30% and fiber length are 5, 10 and 15 mm. Testing of sound absorption frequency are 250, 500, 1000, 2000 and 4000 Hz. The results of research show that  the highest value of sound absorption coefficient is on  the composites with composition of 10 mm fiber length and 30% fiber volume fraction, that is 0.550828. The values are included in the class “Sound Absorption Coefficient Class D (Extremely absorbing)” with the range 0.40 – 0.60 based on ISO standard 11654:1997.

scholarly journals SIFAT PENYERAPAN BUNYI PADA KOMPOSIT SERAT BATANG PISANG (SBP) – POLYESTER

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Khusnul Khotimah ◽  
Susilawati ◽  
Harry Soeprianto
Keyword(s):  
Absorption Coefficient ◽  
Physical Properties ◽  
Sound Absorption ◽  
Volume Fraction ◽  
Alkali Treatment ◽  
Sound Level ◽  
Sound Absorption Coefficient ◽  
Fiber Volume ◽  
The Matrix ◽  
Banana Stem

This research conducted to find the physical properties of the absorption of sound from banana stem fiber (Serat Batang Pisang/SBP) with polyesters’ matrix. The sound absorbent material made with a variety of different volume fraction composition. The comparison between the SBP and the volume fraction of the polyester is made of 30%: 70%, 40%: 60% and 50%: 50%. The method of research was done in three stages: making banana stem fiber, manufacturing composite and testing of composite SBP. Composite testing includes physical properties (sound absorption). Preparation of the samples started by taking a banana stem, decomposition banana stem fiber, alkali treatment with NaOH 4%, then mixing the SBP with the matrix  polyester. Manufactured the composites by press the materials on the molding for 12 hours, then tested to find physical properties. Sound absorption test performed using a signal generator and a sound level meter with the principle of the impedance tube method through acoustic box approach as a reference. The results of the study showed that SBP with polyester composite capable to absorb the sound with sound absorption coefficient α = 0.84 at 50% fiber volume fraction. Thus SBP composites can absorb sound for low and medium frequency, based on the standard ISO 11654:1997 (E) where the minimum of sound absorption coefficient of acoustic materials is α = 0.15. Keywords: Composite, banana stem fiber, sound absorber materials, polyester.

A New Theory for the Debonding of Discontinuous Fibers in an Elastic Matrix

1989 ◽  
Vol 170 ◽  
Author(s):  
Christopher K. Y. Leung ◽  
Victor C. Li
Keyword(s):  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Interfacial Strength ◽  
Fiber Composites ◽  
Short Fiber ◽  
Fiber Volume ◽  
Physical Reason ◽  
Pull Out

AbstractThe mechanical properties of fiber composites are strongly influenced by the debonding of fibers. When an embedded fiber is loaded from one end, debonding can occur at both the loaded end and the embedded end. Existing theories neglect the possibility of debonding from the embedded end and are thus limited in applications to cases with low fiber volume fraction, low fiber modulus, high interfacial strength/interfacial friction ratio or short fiber length. A new twoway fiber debonding theory, which can extend the validity of one-way debonding theories to all general cases, has recently been developed. In this paper, the physical reason for the occurrence of two-way debonding is discussed. The limit of validity for one-way debonding theories is considered. One-way and two-way debonding theories are then compared with respect to the prediction of composite behaviour. The determination of interfacial parameters from the fiber pull-out test will also be described.

Development of a Constitutive Theory for Short Fiber Yarns: Mechanics of Staple Yarn Without Slippage Effect

1992 ◽  
Vol 62 (12) ◽  
pp. 749-765 ◽  
Author(s):  
Ning Pan
Keyword(s):  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Stress Transfer ◽  
Transversely Isotropic ◽  
Short Fiber ◽  
Constitutive Theory ◽  
Fiber Volume ◽  
Shear Moduli ◽  
Yarn Twist

This article reports an attempt to develop a general constitutive theory governing the mechanical behavior of twisted short fiber structures, starting with a high twist case, so that the effect of fiber slippage during yarn extension can be ignored. A differential equation describing the stress transfer mechanism in a staple yarn is proposed by which both the distributions of fiber tension and lateral pressure along a fiber length during yarn extension are derived. Factors such as fiber dimensions and properties and the effect of the discontinuity of fiber length within the structure are all included in the theory. With certain assumptions, the relationship between the mean fiber-volume fraction and the twist level of the yarn is also established. A quantity called the cohesion factor is defined based on yarn twist and fiber properties as well as on the form of fiber arrangement in the yarn to reflect the effectiveness of fiber gripping by the yarn. By considering the yarn structure as transversely isotropic with a variable fiber-volume fraction depending on the level of twist, the tensile and shear moduli as well as the Poisson's ratios of the structures are theoretically determined. All these predicted results have been verified according to the constitutive restraints of the continuum mechanics, and the final results are also illustrated schematically.

Strength and Fracture of Unidirectional Green Composites Reinforced by Hemp Fiber

2009 ◽  
Vol 417-418 ◽  
pp. 89-92
Author(s):  
Hitoshi Takagi ◽  
Koujirou Itotani
Keyword(s):  
Mechanical Properties ◽  
Fracture Behavior ◽  
Fiber Volume Fraction ◽  
Polyester Resin ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Stress Transfer ◽  
Fiber Volume ◽  
Hemp Fiber ◽  
Thermoset Composites

In this paper, unidirectional Manila hemp fiber-reinforced thermoset composites were fabricated and their mechanical properties and fracture behavior were also investigated. Both unsaturated polyester resin and epoxy resin were used as matrix polymer. The tensile strength and Young’s modulus of the epoxy-based composites reached the maximum of 520 MPa and 17 GPa at the fiber volume fraction of 72%, respectively. Such excellent mechanical properties are seemed to be derived both from a good permeability of resin into hemp fiber bundles and from enough stress transfer between fiber and matrix.

scholarly journals The Effects of Fiber Length and Volume on Material Properties and Crack Resistance of Basalt Fiber Reinforced Concrete (BFRC)

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xinzhong Wang ◽  
Jun He ◽  
Ayman S. Mosallam ◽  
Chuanxi Li ◽  
Haohui Xin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Basalt Fiber ◽  
Physical And Mechanical Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Shrinkage Cracking

Basalt fiber reinforced concrete (BFRC) has been widely utilized in various constructions such as buildings, large industrial floors, and highways, due to its excellent physical and mechanical properties, as well as low production cost. In order to address the influence of basic parameters such as fiber volume fraction (0.05∼0.40%), fiber length (12∼36 mm) of BF, and compressive strength (30, 40, and 50 MPa) of concrete on both physical and mechanical properties of BFRC including compressive strength, tensile and flexural strength, workability, and anti-dry-shrinkage cracking properties, a series of standard material tests were conducted. Experimental results indicated that clumping of fibers may occur at relatively higher fiber volume fraction resulting in mixing and casting problems. Based on experimental values of mechanical properties and anti-dry-shrinkage cracking resistance of BFRC, the reasonable basalt fiber length and fiber volume fractions are identified. The addition of a small amount of short basalt fibers can result in a considerable increase in both compressive strength and modulus of rupture (MoR) of BFRC and that the proposed fiber length and content are 12.0 mm and 0.10%∼0.15%, respectively. As the length of basalt fibers increases, the development of early shrinkage cracks decreases initially and then increases slowly and the optimal fiber length is 18.0 mm. Results of the study also indicated that early shrinkage cracks decrease with the increase of fiber volume fraction, and when the volume fraction of 0.20% is used, no cracks were observed. All the findings of the present study may provide reference for the material proportion design of BFRC.

SOUND ABSORPTION COEFFICIENT OF NATURAL FIBRES HYBRID REINFORCED POLYESTER COMPOSITES

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Abdul Hakim Abdullah ◽  
Afiqah Azharia ◽  
Farrahshaida Mohd Salleh
Keyword(s):  
Absorption Coefficient ◽  
High Frequency ◽  
Sound Absorption ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Natural Fibres ◽  
Sound Absorption Coefficient ◽  
Function Technique ◽  
Sound Insulation

Natural fibres have been known of its good acoustic damping properties and therefore, these materials could be used as a sound insulation in many applications. The main purpose of this investigation is to analyze the sound absorption coefficient of sugarcane baggase fibre, banana fibre and its hybrid based composites under various fibre volume fractions. Bone dry test specimens of 10%, 20% and 30% fibre volume fraction were treated with sodium hydroxide (NaOH) prior to composites fabrication using polyester as binder. The pre-tested specimens were examined using scanning electron microscope and electronic analytical balance to analyze physical and dimension characteristic. The sound absorption frequencies were measured using by the two-microphone transfer function technique in the impedance tube that has a 100 mm diameter for low frequency and 28 mm for high frequency, 0 Hz to 4000 Hz respectively. The result indicated that in low and high frequency, the combination of different natural fibres produced better sound absorption coefficient rather than using the natural fibre as individual. The results also demonstrated that the higher amounts of fibre volume fraction are affecting frequencies broadening, hence promising better sound absorbing capacity. 

The Characterization of Discontinuous Carbon Fiber Mat Reinforced Epoxy Composite Materials

2015 ◽  
Vol 1110 ◽  
pp. 77-81
Author(s):  
Eun Soo Lee ◽  
Daniel Buecher ◽  
Si Hoon Jang ◽  
Dae Young Lim ◽  
Ki Young Kim
Keyword(s):  
Carbon Fiber ◽  
Fiber Length ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Physical And Mechanical Properties ◽  
Void Content ◽  
Reinforced Composites ◽  
Fiber Volume ◽  
Fiber Fabric

The carbon fiber mat preforms are prepared by an air laid method with different fiber lengths of 10mm, 30mm and 50mm to characterize the resultant discontinuous composites. The composites are manufactured by a vacuum assisted resin infusion (VaRI) molding technique with the use of epoxy resins to investigate the effects of carbon fiber length on their physical and mechanical properties. The void content and thickness of the composites decrease with the increase in the fiber length at the same VaRI processing conditions. The tensile, flexural, impact properties of the composites are improved by increasing the fiber length in the textile preforms. By comparing with those of carbon fiber fabric reinforced composites, the discontinuous composites demonstrate the excellent performance in strength and modulus in spite of lower fiber volume fraction.

Sign in / Sign up

Export Citation Format

Share Document