Hemp fibre mat reinforced polyester composites were fabricated using a conventional sheet moulding compound (SMC) process. The influence of fibre and CaCO 3 filler content on strength and stiffness of the HF-SMCs is reported and compared with data for chopped glass fibre reinforced sheet moulding compounds (GF-SMCs). In addition the influence of alkaline and silane treatments of the hemp fibres is evaluated. The experimental data is compared to modified versions of the Cox-Krenchel and Kelly-Tyson models, supplemented with parameters of composite porosity to improve the prediction of composite tensile properties. A good agreement was found between the modified models and experimental data for strength and stiffness. The results indicate that HF-SMCs are of interest for lowcost engineering applications that require high stiffness to weight ratios.

This paper describes the results of falling weight impact tests on natural fibre reinforced polyester composites fabricated using a conventional sheet moulding compound (SMC) process. The influence of hemp fibre and CaCO 3 filler content on the penetration energy of hemp fibre reinforced sheet moulding compound (H-SMC) is reported and compared with glass fibre reinforced sheet moulding compound (G-SMC). To evaluate the influence of fibre/matrix interfacial adhesion on the impact behaviour of these H-SMCs, the hemp fibres were treated with alkaline and silane treatments, as well as a combination of these treatments. A simple mechanistic model is proposed for these natural fibre composites and is used to obtain more insight into the impact behaviour of the composites as well as to provide guidelines to compare the experimental data with theory.

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The fracture toughness properties, in terms of stress intensity factor K Ic and strain energy release rate G Ic , of hemp fibre mat-reinforced sheet moulding compound (H-SMC) are measured using the compact tension (CT) method and compared with those of glass fibre-reinforced SMC (G-SMC). Three material parameters were considered for composite optimisation: fibre volume fraction, CaCO 3 filler content and hemp fibre surface treatments using either alkaline, silane or a combination of these two treatments. The highest fracture toughness for H-SMC composites was obtained at a fibre loading of around 30 vol.-%, while it was also shown that the fracture toughness properties of H-SMC are sensitive to mineral filler content. Surface treatment of the hemp fibres using a combined alkaline-silane treatment resulted in a significant improvement in fracture toughness of H-SMC composites. Optimised H-SMC composites exhibited fracture toughness properties similar to those of G-SMC at fibre contents of 20 vol.-%, with K Ic values of around 6 MPa.m −1/2 .

Flow in streams and rivers typically erodes the banks, causing channel bank migration laterally, resulting in loss of nearby land, modification in channel morphology, excessive sediment transport, and water quality degradation. A spur dike is a hydraulic structure placed at the channel bank projecting outward to guide or divert the flow away from the bank, thus protecting it from erosion. The stability of the riverbed and banks is influenced by turbulent characteristics such as three-dimensional velocity distribution, turbulent kinetic energy, Reynolds shear stress, turbulent intensity, and bed shear stress. The researchers found that these turbulence parameters are instrumental in sediment movement along the channel's bed and from its banks. Spurs dikes are a significant river training structure provided along the river bank to protect from erosion. Several aspects related to spur dikes, such as their geometry, physical features, design considerations, flow and scour patterns, etc., are critically reviewed in this paper. Despite the numbers of literature in the field of turbulent characteristics and scour depth around spur dike, the role of vegetation and the effect of seepage around spur dike still remains an unexplored area. These knowledge gaps of spur dikes in field conditions are discussed for future studies.