Research on natural-fiber-reinforced polymer composite is continuously developing. Natural fibers from flora have received considerable attention from researchers because their use in biobased composites is safe and sustainable for the environment. Natural fibers that mixed with Carbon Fiber and or Glass Fiber are low-cost, lightweight, and biodegradable and have lower environmental influences than metal-based materials. This study highlights and comprehensively reviews the natural fibers utilized as reinforcements in polyester composites, including jute, bamboo, sisal, kenaf, flax, and banana. The properties of composite materials consisting of natural and synthetic fibers, such as tensile strength, flexural strength, fatigue, and hardness, are investigated in this study. This paper aims to summarize, classify, and collect studies related to the latest composite hybrid science consisting of natural and synthetic fibers and their applications. Furthermore, this paper includes but is not limited to preparation, mechanism, characterization, and evaluation of hybrid composite laminates in different methods and modes. In general, natural fiber composites produce a larger volume of composite, but their strength is weaker than GFRP/CFRP even with the same number of layers. The use of synthetic fibers combined with natural fibers can provide better strength of hybrid composite.

Nowadays, the hybridization of natural and glass fiber has promised several advantages as a green composite. Nevertheless, their different characteristics lead to poor mechanical bonding. In this work, agel fiber and glass fiber was used as reinforcements, and activated carbon filler was added to the polymer matrix of a hybrid composite to modify its characteristics and mechanical properties. A tensile and bending test was conducted to evaluate the effect of three different weight percentages of activated carbon filler (1, 2, and 4 wt%). Vacuum-assisted resin infusion was used to manufacture the hybrid composite to obtain the high-quality composite. The results have revealed that adding 1 wt% filler yielded the most optimum result with the highest tensile strength, flexural strength, and elastic modulus, respectively: 112.90 MPa, 85.26 MPa, and 1.80 GPa. A higher weight percentage of activated carbon filler on the composite reduced its mechanical properties. The lowest test value was shown by the composite with 4 wt%. The micrograph observations have proven that the 4 wt% composite formed agglomeration filler that can induce stress concentration and reduce its mechanical performance. Adding 1 wt% filler offered the best dispersion in the matrix, which can enhance better load transfer capability.

In this paper, the mechanical properties of composite materials are subjected to statistical analysis. This study aimed to determine the value of B-Basis strength parameters of carbon composite material with UD-00, UD-900, fabric-00, fabric-900 from the results of tensile and compression tests. The maximum normal residual test was used for outlier identification and k-sample Anderson’s darling test to determine whether parameters can be processed as one large group of data. The scope of this study focused on evaluating B-Basis values using two methods: Weibull and ANOVA. The results showed that Weibull distribution method could be applied to analysis the data and produced a confidence level of 95%. ANOVA method however, could not be applied to specific data which were the tensile strength of UD 00 with a non-tabbing treatment. This was due to the inhomogeneous of the data.

This research was done to evaluate flexural properties (flexural strength, flexural modulus, and failure mode) of Bambu Tali (Gigantochloa Apus) composite. Lycal 1101 was used as matrix. Two types of laminate were tested in four point bending, unidirectional (00/00) s and symmetric cross ply (00/900) s. Results were then compared with numerical simulation using MSC PATRAN-NASTRAN to determine flexural strength and failure mode prediction for both specimens. All specimens were manufactured using cold press manufacturing method. Results show there was around 28% reduction in flexural strength from unidirectional specimen to symmetric cross ply. Numerical simulation results on failure mode prediction show good agreements with actual four point bending test.

The commercial feasibility of active noise control (ANC) is very promising due to its capability beyond passive noise control (PNC). To some extent ANC becomes a complement of PNC. The active noise reduction is also capable and beneficial in reducing noise selectively. However, the active noise reduction using a conventional secondary source can become very complicated if a significant noise level reduction is required, since a large number of secondary sources will be needed. The active noise reduction is also less effective for reducing high-frequency noise. With such perspectives, a novel approach has been developed using a multipole secondary source to addressthe problems mentioned. In addition, the multipole secondary source will be used for numerical simulation of noise reduction in of propeller noise source in a free field.