In this study, Hypermesh and Catia V5 software were adopted for finite element analysis (FEA) of a vehicle B-pillar. The design objectives were to optimise the B-Pillar such that the maximum displacement, weight, and maximum stress value of B-Pillar is minimised without compromising its yield strength and impact resistant properties. This is significant for the improvement of a vehicle's crashworthiness and ensuring the safety of passenger(s) during road accidents. This study initially analysed a given B-pillar design after being subjected to an even force of 140kN. The result produced von Mises stress of 1646MPa and deflection of 5.9mm. To ensure that EuroCAP directives were met, the BPillar was reinforced by adding extra steel plates to its inner surface and applying seam welding to ascertain their fusion and analysed using the same force of 140kN. Analysis of the reinforced B-Pillar design produced maximum von Mises stress of 673MPa with a maximum displacement value of 2.39mm. The optimised B-Pillar design was reinforced with 1.7kg steel plate with the overall mass of the B-Pillar amounting to 4.2kg of the total design compared to the original B-Pillar which had a total mass of 6kg. The optimised BPillar possessed less weight beside capable of resisting a force of 140kN with von Mises stress and displacement rate lower than the original B-Pillar. Thus, this indicates improvement in the tensile strength, stiffness, and impact resistant behaviour against collision forces by acting sideward on vehicles during road accidents. This can save such vehicles and passengers from severe damage that may result in loss of lives and properties. Hence, B-Pillar must be designed following the existing standards and tested before installation on vehicles to avoid unforeseen catastrophes.

Helical compression spring plays a vital role in vehicle application as it improves ride index, sustains the vehicle against extreme degrees of vibration and stress induced on the suspension system as a result of uneven road. Depending on the extent of load acting on the suspension system, material selection, design considerations and manufacturing processes, longevity and performance of the spring may be sustained, otherwise the spring may fail prematurely under severe loading condition. In this study, compression spring was designed using high carbon steel, stainless steel and chrome vanadium steel and the designed spring models were simulated for maximum Von-mises stress, maximum resultant displacement and resultant strain. Curb weight of the vehicle was considered in the analysis which involves the weight of the car with all fluids and components but without the driver, passengers, and cargo. At the end of the simulation, the three materials remained within the limit of their elasticity without any significant sign of failure under the applied load of 3888N. However, the difference between Von-mises stress obtained for Chrome vanadium and its yield strength was the highest (653MPa) followed by stainless steel (235MPa) before high carbon steel (109MPa). This implies that at increasing loading conditions, high carbon steel will be the first material to fail during operation, whereas, stainless steel and chrome vanadium may exhibit sustained level of longevity before failure as a result of the high chromium content and other alloying elements that gives them a better quality but at relatively high cost compared to high carbon steel which can satisfactorily undergo its service condition at relatively low cost.

Remotely controlled hydraulic bottle jack was designed in this study to alleviate the difficulties encountered during auto servicing that requires certain choice of elevation. Major components of the hydraulic jack were housed in a metal casing of 220mmx220mmx180mm with 2mm thickness. Curb weight (weight of the car with all fluids and components but without the driver, passengers, and cargo) of several cars ranging from 1086kg-1970kg were determined using a scale at nearby automobile shop. Considering the weight of individual cars that the designed hydraulic jack elevated, the time required to attain upward stroke of the piston and specific height of elevation was recoded accordingly. The time varied between 1.2 minutes with specific height of 150 mm and 1.44 minutes with specific height of 112 mm. Half weight of 1970 kg (985 kg) was used as the load case in Finite Element Analysis (FEA) to check the stress deformations, displacement and equivalent strain. Maximum von-mises stress of 8.465x106 N/mm^2 was obtained which is below the yield strength of the jack piston material. Maximum displacement of 2.999x10-1 mm and maximum equivalent strain of 3.56x10-3. Factor of safety was chosen on a scale of 1-10, and the colour chart in the analysis indicated blue colour in the range of 7-10 throughout the jack assembly. This was an indication that the jack is safe to operate under the aforementioned applied load. Therefore, adoption of remotely controlled hydraulic bottle jack can save time and energy required to elevate vehicles to working height.

In this study, a two stroke internal combustion engine was successfully modeled as a closed cycle with the intake, compression, expansion and exhaust processes considered in two strokes of the reciprocating piston. The in-cylinder combusted gases with respect to air-fuel mixture of 14.4:1 in the two stroke engine model were analyzed, showing the dynamics of the combusted gases, the flame pressure and temperature trajectories. It was observed that provided compression and expansion takes place at air-fuel mixture near ideal condition (14.7:1), the combusted gas temperature which occurred in the range of 293.92-3000.60 K is directly proportional to the cylinder gas pressure which occurred in the range of 60.76-80.20 bar. With a heat transfer coefficient of 581.236 W/m2K, the maximum temperature of the IC engine material was found to be 2367.56K at equilibrium and the maximum shear stress was found to be 176 x 102 MPa (1.76 x 105 bar). The 14.4:1 air-fuel mixture implies that 26% O2, 73% N2 and 1% trace gases are the in-cylinder air constituent that will react with 1 mole of hydrocarbon to form the combusted products of 96.2% CO2, 3.2% H2O and 0.6% N2. This will vary in conditions where the air-fuel mixture changes. Keywords: Modelling, Gas dynamics, Two stroke, IC engine, Air-fuel mixture.