A Comprehensive Assessment of Commercial Process Simulation Software for Compression Moulding of Sheet Moulding Compound

With a growing interest in the application of carbon fibre Sheet Moulding Compound (SMC), a number of commercial software packages have been developed for the simulation of compression moulding of SMC. While these packages adopt different algorithms and meshing strategies, the constitutive material model and processing control are usually adapted from injection moulding process simulation. Little has been done in the literature for assessing the capabilities of these software as design tools, and more importantly, validating the process simulation results using experimental data. This paper aims to provide an independent and comprehensive assessment of existing well-known process simulation software for SMC compression moulding. The selected software will be compared in terms of material models, and available processing settings in order to determine their robustness as a compression moulding design tool. The predictive accuracy of the software will also be assessed by comparing the compression force and filling patterns against the experimental data.

On an application of multi-material composite laminates in the aerospace sector

This paper explores the possibility to use shredded thermoplastic laminates as one of the plies within a laminate. The focus lies in potential performance decrease due to the presence of such compounds within the laminate. For this purpose, a typical application of a stampformed thermoplastic-based laminate is taken as a basis. In this application, the replacement of mid-plane layers by a moulding compound is considered. The performance knockdown is evaluated using a series of tests typically related to the application. The results of bending, bearing and curved beam tests are reported and analysed. The results show that the replacement of continuous fibres by shredded laminates does not affect significantly the performance of the material for the chosen properties. The applicability of such hybrid laminates is further discussed based on these results.

COLLECTIONS OF CLAY PRODUCTS FROM A PALAEOETHNOBOTANICAL POINT OF VIEW

The basis of the study is the work of N. M. Kravchenko and G. O. Pashkevych in 1985 with the addition of the author’s observations. The author analyzed options for the penetration of palaeoethnobotanical materials into the moulding compound as well as their value for interpreting these findings. The reasons for penetration of materials to molding compound, groups of clay products and their informative value, advantages and disadvantages of this method of information gathering and further perspectives of research and interpretation were reviewed. Plant impurities were found in most categories of clay products. Conventionally they include utensils, probable architectural details and / or «stationary» utensils, tools as well as figurines, and other products that have no practical application. According to the scheme proposed by N. M. Kravchenko and G. O. Pashkevych four factors of the penetration of plant residues into the molding compound were identified. Factor 4 «The use of vegetable impurities as a backing between the stand and the crude billet of clay product (pot, vessel)» is of the less informative value. Its value could lie in the possibility to establish the season of manufacturing of pottery due to the backing. Factor 2 «Adding grain to a molding compound for ritual purpose» now can be significantly expanded due to ordinary household items, such as large pots for grain storage, firepans / pans and even furnaces. Factor 1 «Technological technique, in which crushed plant mass was added to reduce shrinkage of products during their drying and firing» also usually does not add information about palaeoethnobotanical materials. The only factor important for statistical surveys and the establishment of the grain economy is factor 3 «Accidental ingress of grains or seeds into the molding compound during the manufacture of pottery».

Post-impact damage tolerance of natural fibre-reinforced sheet moulding compound

Natural fibre composites are of interest for a wide range of semi-structural applications in the building, construction and automotive sector. For a number of these applications, the evaluation of performance degradation after impact is of some relevance. The present work focused on the influence of fibre volume fraction and fibre surface treatment on the residual load-bearing capability of hemp fibre-reinforced sheet moulding compound (H-SMC) after non-penetrating impacts. Post-impact flexural strength and stiffness of H-SMC decreased linearly with increasing impact energy. At higher impact energy levels, the residual flexural strength of H-SMC improved with increasing fibre volume fraction. However, for the same amount of absorbed energy, the residual strength or damage tolerance capability of glass fibre-reinforced sheet moulding compound was about twice that of H-SMC. Composites based on surface treated hemp fibres showed a slight improvement in residual flexural strength, particularly for systems based on hemp fibres treated with a combined alkaline and silane surface treatment. Surface treated systems showed improved levels of adhesion and increased levels of energy absorption through potential mechanisms such as debonding, pull-out or fibre fibrillation.