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This study aims to investigate the impact and compressive strength properties of corn husk fibre (CHF)/polyester composites. The composites were subjected to water immersion treatment at two different durations. A polyester mixture with CHF of different fibre volume fractions was formed via hot press at 107 °C for 5 min. All composites were soaked in water for 24 and 72 h. Characterisation of impact and compressive strength, water absorption and thickness swelling properties of the composites were evaluated. The morphology of surface fractures of the composites was also analysed using scanning electron microscopy (SEM). Results show that the impact and compressive strength, thickness swelling and water absorption properties of the composites initially increased after 24 h of dyeing treatment. After soaking for 72 h, the moisture absorption and swellability properties of each composite increased by approximately 0.24%–1.38% and 0.08%–1.04%, respectively. Consequently, the impact strength of the composites increased, but the compressive strength decreased due to the weakened interface of polyester–fibres. SEM images show the interface between the fibres and the spread of fibres and voids. These results indicate that CHF composites can be an alternative for wood composites as construction materials.

When wood structures are exposed to high temperatures, they will decompose to provide a char layer and pyrolysis zone, an insulating material that inhibits further degradation. This experimental study aims to determine the char thickness and pyrolysis of solid wood exposed to fire for 30, 45, and 60 minutes. The post-fire shear strength has also been evaluated. The solid woods were locally from Nusa Tenggara Island, namely Jati Putih, Bajur, and Rajumas. According to the Indonesian National Standard of the heating curve for structures, the temperature growth was SNI-1741: 2008. Obtained The char layer's highest average thickness was within 60 minutes of combustion with the highest temperature of 1055oC. The char layer for Jati Putih, Bajur, and Rajumas are 2.12 mm, 7.89 mm, and 6.53 mm. Meanwhile, the pyrolysis layers are 8.78 mm, 9.13 mm, and 14.82 mm, respectively, for Jati Putih, Bajur, and Rajumas. Besides, the post-fire shear strength of all wood species shows an increase in shear strength in the core. Wood can still sustain the load during a fire because there is a char layer preventing the core section from immediately exposed to the fire.

Polymeric composites reinforced with natural fibers have raised more attention as the alternative building materials. In this work, natural fiber composites prepared from jute and hemp fiber were proposed for the intermediate layer of a hybrid sandwich panel. This paper presented the flexural behavior of the newly developed hybrid sandwich panel which included the comparison of the ultimate load, load-deflection behavior, load-strain behavior and failure modes. The study was designed as a single factor experiment where the performance of hybrid sandwich panels containing jute fiber composite (JFC) and hemp fiber composite (HFC) as the intermediate layer was compared to the control (CTR) which was a conventional sandwich panel without an intermediate layer. A static flexural test under a four-point bending load scheme was performed in accordance with the ASTM C 393-00 standard. Aluminium sheet was used as the skins, while expanded polystyrene (EPS) was employed for the core. The testing was performed using a 100 kN servohydraulic machine with a loading rate of 5 mm/min. The applied load, displacement and strains were obtained using data logger. The results demonstrated that the hybrid sandwich panel exhibited a more superior performance than the conventional sandwich panels. The intermediate layer contributed significantly to enhancing the load carrying capacity of the hybrid sandwich panel. The load carrying capacity of hybrid panel with the JFC intermediate layer was 29.60% higher than the conventional sandwich panel, and correspondingly 93.46% higher for the sandwich panel with the HFC intermediate layer. The hybrid sandwich panels also developed a much larger area under the load-deflection curve, indicating greater toughness. The introduction of intermediate layer helped the hybrid sandwich panels to sustain a larger strain prior to reach their ultimate loads, resulting in a higher deformation capability. Indentation and core shear were observed as the failure mode of the conventional sandwich panel. Meanwhile, core shear and delamination were identified as the failure mode of the hybrid sandwich panel. Refereed/Peer-reviewed

This paper discusses the results of an experimental investigation on the shear properties of natural fibre composites using the V-Notch or Iosipescu shear test. The natural fiber composites were made of jute and hemp fibers reinforced epoxy polymer resin. The testing was conducted using an MTS machine equipped with a 10 kN load cell in accordance with the ASTM standard D5379M. The testing machine was set-up to apply a load with a speed of 2 mm/min. It was found that the jute fiber composites (JFC) have an average shear stress of 25.56 MPa, while the hemp fiber composites (HFC) have an average value of 22.46 MPa. The loaddisplacement graphs showed a nearly linear trend at the initial loading stage that slightly deflected prior to reaching the maximum load. Most of the specimens in both groups, JFC and HFC, showed fractures in a diagonal cracking pattern, known as an off-axial failure mode. Only a few specimens collapsed across the notched section. Both are customary failure modes for this type of shear test.

This paper presents a comparison of theoretical and experimental deflection of a hybrid sandwich panel under four-point bending load. The paper initially presents few basic equations developed under three-point load, followed by development of model under four-point bending load and a comparative analysis between theoretical and experimental results. It was found that the proposed model for predicting the deflection of hybrid sandwich panels provided fair agreement with the experimental values. Most of the sandwich panels showed theoretical deflection values higher than the experimental values, which is desirable in the design. It was also noticed that the introduction of intermediate layer does not contribute much to reduce the deflection of sandwich panel as the main contributor for the total deflection was the shear deformation of the core that mostly determined by the geometric of the samples and the thickness of the core. Refereed/Peer-reviewed

This paper presents the significance analysis of a new type of hybrid composite sandwich wall panel which can be manufactured as modular panelised system. Two different types of natural fibers reinforced plastics (NFRP) laminate were incorporated into the new sandwich panel as an intermediate layer. The significance analysis in this research has been carried out using analysis of variance (ANOVA). As the aim of the analysis is to select the most appropriate natural fiber composites for the intermediate layer, the experiments were arranged as a single factor experiment in which 3 levels of a factor have been examined. The factor refers to the type of intermediate layer used in the sandwich panel. The result of this study shows that the incorporation of intermediate layer has significantly enhanced the load carrying capacity of the sandwich panels. Refereed/Peer-reviewed

This paper presents a statistical aspect of experimental study on the in-plane shear behaviour of hybrid composite sandwich panel with intermediate layer. The study was aimed at providing information of how significant the contribution of intermediate layer to the in-plane shear behaviour of new developed sandwich panel. The investigation was designed as a single factor experimental design and the results were throughly analysed with statistics software; Minitab 15. The panels were tested by applying a tensile force along the diagonal of the test frame simulating pure shear using a 100 kN MTS servo-hydraulic UTM. The result shows that the incorporation of intermediate layer has sinificantly enhanced the in-plane shear behaviour of hybrid composite sandwich panel. The statistical analysis shows that the value of F0 is much higher than the value of Ftable, which has a meaning that the improvement provided by the incorporation of intermediate layer is statistically significant.

In this study, three different types of lignocellulosic composite materials have been incorporated in sandwich panel structure as an intermediate layer. The experiment was statistically designed based on single factor analysis scheme. The results of experiments have been analyzed using analysis of variance (Anova) followed by Tukey's, Fisher's and Dunnet's tests to obtain the information of how significant those materials contribute to the flexural strength of sandwich panel structure. The total number of samples tested was 48 beams. The results show that the introduction of lignocellulosic composites materials, that are hardboard, medium density fibre (MDF) and plywood, has significantly improved the flexural strength of sandwich panel. The range of improvement contributed by the presence of lignocellulosic composites intermediate layer was around 100-150% for samples with balsa core and 130-150% for samples with polystyrene core. The result of this study shows the potential of lignocellulosic composite material to be developed further for producing more sustainable sandwich panel. Refereed/Peer-reviewed

In this paper, we present a comprehensive analytical and experimental investigation for the determination of the air flow resistivity and porosity of sound absorber composite. The ratio of the volume fraction of fiber and polyester resin is 15, 25, 35, 55 and 65 (%).The dimensions of the absorbent composite sample are 29 mm x 20 cm (diameter x thickness). Porosity and Air flow resistivity of composites have been investigated. The results showed that the porosity of the composites increased with increasing amount of fiber due to the interface between fiber and resinless dense. In contrast, the air flow resistivity values are lower with a denser resin and fiber interface.

This paper presents the structural behavior of newly-developed hybrid structural insulated panels (SIPs) formed by incorporating lignocellulosic composites-jute fiber composite (JFC) and medium-density fiber (MDF)-as intermediate layers between aluminum skin and an expanded polystyrene (EPS) core. The investigation was conducted as an experimental work. A four-point bending load was performed to create pure bending conditions, and the samples were prepared in accordance with ASTM C 393-00 standards. Testing was performed using a 100 kN servo-hydraulic machine with a loading rate of 5 mm/min. The results show that the incorporation of intermediate JFC or MDF layers enhanced the flexural behavior of the SIPs. The ultimate loads of hybrid SIPs with JFCs or MDF were, respectively, approximately 62.59% and 168.58% higher than the ultimate load achieved by SIPs without intermediate layers. Hybrid SIPs exhibited a much larger area under the load-deflection curve than those of conventional SIPs; this points to the toughness of the material and its ability to sustain larger compression strain prior to reaching their ultimate loads, which prevents them from prematurely failing under buckling or indentation. Refereed/Peer-reviewed