PurposeBallistic missile-resistant impact panels have seen fair advancement over the years, especially in military applications. However, high cost, as well as a changing materials landscape, has impressed the need for a deeper understanding of impact mechanism as well as of new permutations in design strategy development. Parameters such as projectile impact angle, panel impact location as well as application of multilayer sandwich panels are not fully explored and characterised. In this work, finite element method simulation methodology is used on a 25 mm by 25 mm plate of 3.5 mm thickness to investigate the above-mentioned parameters and conditions. Solid elements using Johnson–Cook damage material models are developed. Two common impact angles of 90 and 45° at centre and plate-edge locations are investigated for single-layer titanium alloy and carbon steel panels. Subsequently, a bilayer panel comprising of titanium alloy at the impact layer with the same overall plate thickness is investigated for impact at five different impact speed (ranging from 100 ms-1 to 500 ms-1). The displacements and von Mises stresses are documented for all cases, and it is shown that angular impact angles bring about greater plastic deformations as well as higher fracture likelihood compared to normal angle impact. Findings also indicate that with an addition of 1 mm thick Ti-6Al-4V front bilayer, the impact resistance of the high carbon steel is significantly improved (up to twice the impact load), especially at higher impact velocities. The study documents the properties of titanium alloy–carbon steel bilayer armoured panel, which shows good promise for its implementation due to its superior performance and its cost-savings potential.Design/methodology/approachIn this work, finite element method simulation methodology is used to investigate the above-mentioned parameters and conditions. Solid elements using Johnson–Cook damage material models are developed. Two common impact angles 90 and 45° at centre and plate-edge locations are investigated for single-layer titanium alloy and carbon steel panels, and, subsequently, a bilayer panel comprising of titanium alloy for the outer layer is investigated for the combination of the same aforementioned materials. Five different impact speed effects are studied.FindingsThe effects and trends of displacements and stresses are documented for all cases and shown to indicate angular impact angles bringing about greater plastic deformations as well as higher fracture likelihood compared to normal angle impact. Findings also show that with an addition of 1 mm thick Ti-6Al-4V front bilayer, the impact resistance of the high carbon steel is significantly improved, especially at higher impact velocities.Originality/valueThe study documents the properties of titanium alloy–carbon steel bilayer armoured panel, which shows good promise for its implementation due to its superior performance and its cost-savings potential.

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Pigment levels are known to have an effect on defect formation of the plastic injection moulding parts. Warpage, Shrinkage and Flash are common defects that were found during plastic injection moulding process. It was found that the pigment does play a role in the formation of defects on the plastic injection moulding parts. The main finding of this case study is to analyse and study the warpage, shrinkage and flash defects that were found in the Plastic Injection Moulding (PIM) parts which are moulded with different pigmentation percentages. It is also to identify the effects of the different pigments colours on the moulding quality of the parts when the pigment percentage is made constant. In this research, the dog bone design was used as the experimental specimen. The material used in this study is Polypropylene (PP). The other parameters such as injection pressure, melting temperature and cooling time were set to constant. The only parameter that varies is percentage of pigmentation. Warpage, Shrinkage and Flash defects are measured and calculated to obtain the value of defects. The pigmentation gives a huge effect on Warpage and Flash deformation. The warping and flash increase as the percentage of pigmentation increase. The highest value for warpage and flash are 3.0732 and 1.45304 respectively. Moreover, blue pigment gives the lowest value for Warpage and Flash defect. While yellow has the highest warping and flash defects. However, it was found that shrinkage is not affected by the pigmentation. The shrinkage result is less than 1%.

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