Papers by Keyword: SMC

Abstract: The growing popularity of SMC compression moulding in the automotive industry has led to great interests in process simulation model development. Existing process simulation models are commonly adapted from models originally developed for short fibre composites and lacking experimental validation data. A novel material model specifically developed for SMC flow simulation is proposed in this paper, where the experimental material characterisation is performed using the squeeze flow testing method. The model is validated through simulation of the squeeze flow testing and the accuracy of the model is assessed by comparing the predicted compression forces against experimental data collected from the squeeze flow testing. The proposed new model has demonstrated significant improvement in comparison to existing commercial models in term of compression force prediction, but the predicted compressive forces diverted away from the experimental values towards the end of the test. The predicted cavity pressure distribution has also been investigated and compared to observations reported in the literature where good correlation between predicted pressure distribution and the literature have been achieved.

Abstract: Sheet Molding Compound (SMC) materials offer attractive specific strength and stiffness properties. With an addition of short cycle times, the possibility for complex geometries and a high recycling potential, this material is a promising solution for the manufacture of lightweight components of numerous industrial sectors. Accurate and reliable simulation can contribute to a fast and competitive development process and effectively reduce the time-to-market. Especially, the accuracy of the simulative filling process is crucial to be able to predict the mechanical properties and hence, pave the way to structural parts. An appropriate characterization of the rheological behavior is therefore, crucial for accurate simulation results. To this purpose bar flow tests are performed and the experimental results are compared to the numerical results. A sensitivity analysis is performed to investigate the influence of each parameter on the simulation outcome. Furthermore, guidelines to improve the simulation accuracy and the testing equipment are derived. In the testing method some improvement potential was identified and the necessity for a testing method closer to the compression process could be established.

Abstract: Low Density and Low Pressure Sheet Molding Compounds (LD-LPMC) were prepared by using magnesium oxide paste and crystalline polyester as thickening system to reduce molding pressure and Hollow Glass Microspheres (HGM) as fillers to reduce the density. The molding pressure of LD-LPMC was investigated. The effects of HGM content (0%, 3.8%, 7.6%, 11.4%, 15.2%, 19.0%) on the density, flexural strength and thermal conductivity of LD-LPMC were studied. The results showed that 2-4Mpa was the best molding pressure for the composite materials. With the increase of HGM content, the density, flexural strength and thermal conductivity of LD-LPMC decreased. The thermal conductivity increased with the increase of temperature. When the molding pressure was 3Mpa and the content of the HGM was 7.6%, the density decreased by 13.6%, the flexural strength only decreased by 23.3% and the thermal conductivity (40°C) also decreased by 11.5%, which reflected the low density, high strength and good thermal insulation performance of LD-LPMC.

Abstract: The Innovate-UK-funded Composite Lightweight Automotive Suspension System (CLASS) project, led by Ford Motor Company and partnered by Gestamp UK, GRM Consulting and WMG, investigated the use of carbon fibre reinforced composite materials to decrease the weight of a complex automotive rear suspension component in support of reduction in vehicle emissions. A multi-material design comprising discontinuous fibre composite (C-SMC), aligned fibre composite laminate (prepreg) and steel was developed. A high volume hybrid compression moulding manufacturing process was developed at WMG, achieving total press cycle times of around 5 minutes. Prototype parts were manufactured and evaluated using materials characterisation techniques to validate the manufacturing methods. The optimum C-SMC charge pattern was investigated to achieve complete fill with minimal pre-processing. Destructive and nondestructive analysis of the hybrid parts was performed to understand resultant hybrid material macrostructure. This innovative design and manufacturing process resulted in a component 35% lighter than the original multi-piece steel design.

Abstract: Sheet Molding Compound (SMC) was developed in the 1960s and initially enabled the production of glass fiber reinforced polymer composite (GFRPC) in mass production. Nowadays, both material and process are well established for the production of semi-structural components in various applications from construction industry to automotive components. Currently, approximately 20% of all glass fibers produced in Europe are processed to SMC. In this paper, the use of renewable filler materials in SMC is described. By using those alternative fillers, a density reduction of 20%, while maintaining same processability and mechanical properties of SMC, can be achieved.

Abstract: For electrostatic coating application Sheet Molding Composites (SMC) have to be modified antistatically. By a novel approach several monomeric and polymeric ionic substances were incorporated into the duromeric bulk phase and tested in terms of its antistatic effectiveness. Furthermore the influence of selected additives on the SMC thickening and molding procedure as well as resulting mechanical properties of modified SMC-panels and the powder coating application were studied.

Abstract: The SMC cold temperature asphalt mixture consumed less energy and harmful emission compares with the traditional HMA and WMA, and it can be worked at the subzero temperature or after a long time storage, which makes the construction and maintenance of the asphalt pavement in a special environment (low temperature) and special conditions (without a hot mix station) come true. It has been widely used in Beijing, Xinjiang, Sichuan, Tibet, etc. with a satisfied performance. Highway construction and maintenance technology level of China would be positively promoted by using the SMC asphalt mixtures.

Abstract: In this paper, we present the result of investigations pertaining to the floating photovoltaic energy generation structures. Pultruded fiber reinforced polymer plastics (PFRP) and sheet molding compound (SMC) fiber reinforced polymer plastics (FRP) have superior mechanical and physical properties compared with those of conventional structural materials. Fiber reinforced polymer plastics (FRP) has an excellent corrosion resistance and high specific strength and stiffness, the FRP material may be highly appreciated for the floating photovoltaic energy generation system. The floating photovoltaic energy generation system is analyzed and designed to have sufficient safety. In addition, from the finite element analysis the safety of the structure was also confirmed. Based on the results, structural system is designed, fabricated, and installed at the site.

Abstract: In this paper the problem of guiding a parabolic trough solar concentrator through a system based on a water displacement mechanism is addressed. The actuator mechanism consists of a set of four on/off electrovalves in ”H-bridge” configuration, a small water pump, a sun sensor and two containers half-filled with water, installed on the side ends of the concentrator. To guide and balance the concentrator, a sliding mode controller (SMC) to enable / disable the opening and closing of the valves that control the direction and flow of water between the two containers is proposed. The validity of the implementation of the proposed law of control applied to the actuator mechanism is verified with stability analysis and simulation results.

Abstract: Today's sandwich structures and materials offer a high potential for lightweight design and are being used in various industrial applications. However, the material and manufacturing costs for structural sandwich structures in aerospace and automotive industry are comparatively high. Furthermore the production of lightweight and functional composite-sandwich components is usually characterised by long manufacturing lead times and a high level on manual workload. In this context the production of lightweight, functional and geometric complex sandwich structures consisting of SMC layers and closed cell rigid foams as core material in a single-step compressing moulding process is very promising. By using such a process new design approaches, a high level of functional integration as well as excellent cost, material and resource efficiencies can be realised. This paper deals with the new manufacturing approach, first experimental investigations on the mechanical properties and the estimated potentials for using these high-efficient, lightweight sandwich structures in aviation and automotive industry.