D Challenge Design and Drawings - Coursework Example

Portfolio - САD Challenge design and drawings By Student’s name Course code and name Professor’s name University name City, State Date of submission Design Summary The paper had to design brake pedal using aluminium alloy materials which have been selected. The final drawing has been done for the project using SolidWorks. The pedal shaft for the project has been designed its drawing has been provided. The front and rear brakes have been designed as well as the bias bar. The bias bar has 10mm bias adjustment as well as a width of 3 or 8” and a diameter of 1”. It should have maximum brake of 27.28MPa and front brake lines. It has a safety factor of 1. The results indicated that option 2 indicated that had low density, high-yield strength, and good fracture toughness, wieldable at high temperature as well as very low temperatures, it has also a small elongation percentage as compare to Aluminum alloy. Table of Contents Design Summary 2 Introduction 4 Final Design drawing 4 Materials and fabrication method 6 Material Cost 8 Design optimization methodology 8 Preliminary analysis 10 Conclusion 10 References 11 Introduction In designing brake pedal various approaches were considered however, performance, cost and castability were given priority. The requirements for the materials will be highlighted in this case as well as in the design case. The design issues will include the casting method, the types of alloy, the drawing of the structure and the final drawing in the solid work. Brake pedals should be made stable before being placed in the car. If these proper specifications are followed, it will lead to improved braking efficiency and minimized weight. Inspection of support structures, hydraulic leaks and brake systems should be periodically inspected and repaired. For any brake pedal to be successful in compatibility with the car where it is used, the design and modeling takes into account that brake pedal can withstand various during it use. It has been modeled using SolidWorks software focusing on appearance. The purpose was to make sure the brake pedal is able to perform their duties properly. This will help in coming up with standards which guide in planning preventive and maintenance of the brake pedal. Final Design drawing The final design drawing of the brake pedal has been made and screen shots of the drawing are shown below. Simulation was done for duration of 0.6 seconds where the time interval was 0.003 seconds. The resistance force which was applied on the shaft of the brake pedal was 250N. There is a major concern especially when the proactive maintenance method is undertaken to detect the rolling element of bearings. In addition, there is vibration that is related and connected with the worn bearings which is usually created from the numerous impacts of the numerous metal parts. Figure 1: Pedal shaft Materials and fabrication method In order to design strong brake pedal design, the following specifications for materials will be necessary. In selecting the aluminium alloy for the brake pedal, the following specifications were considered for selection. The specifications specifically considered modulus elasticity, yield strength, ultimate tensile strength, corrosion resistance and elongation of materials. The mechanical properties of aluminium relatively depend on the low pressure permanent mould method. Therefore aluminium alloy materials will be casted using one method that is low pressure permanent mode which has many advantages including good mould durability. Low pressure moulding is best to brake pedal because it does not use a lot of pressure therefore breaking the material is not easy thus maintaining dimensional tolerance. The materials that were considered were aluminium alloys. The materials values are listed below. Through calculation, the stiffness values for the three pairs in the drive line of the brake pedals. Materials performance Requirements Option 1 Option 2 Option 3 Yields strength 200MPa 400 220 180 Modulus of elasticity 14200MPa 14000 14200 14500 Density of the materials 2.7MPa 2.7 2.7 2.7 Ultimate Tensile strength 300MPa 450 350 400 Corrosion resistance (1=Excellent, 5=poor) 1 3 2 1 Ductility (% Elongation) 8% 10% 8% 12% Castability (1=Excellent, 5=poor) 1 2 1 5 Table 1: Specification table The bias bar has 10mm bias adjustment as well as a width of 3 or 8” and a diameter of 1”. It should have maximum brake of 27.28MPa and front brake lines. It has a safety factor of 1. The combination of the above values is generally used during the calculation of the general output values therefore characterizing a certain mechanical condition regarding the brake pedals. As such, the initial values do match up to the overall state of the brake pedals while the ensuing value normally corresponds to a state of the specified bearings. Looking at density, it can be noted that titanium material has the lowest density which is likely to decrease the weight of the brake pedal. Therefore, from the mechanical properties of the two materials, titanium-lithium alloy is selected as a suitable replacement of aluminum alloy The reserve safety factor of 1.0 has been considered in the analysis. This will enable the coverage of unforeseen factors while brake pedal is in the car. Another stress source is thrust misalignment. The trust can be misaligned in any direction, and can lead to extra bending and torsion. The thrust at various angles was input into the structures codes again, this time as a source of shear stress. If Young’s Modulus decreases, the critical stress decreases Material Cost The table below indicates cost per weight and cost per MPa (strength) for all materials under consideration. Material Cost/weight (USD/kg) Cost/Strength (USD/MPa) Option 1 alloy 7.50 0.92 Option 2 alloy 7.02 0.83 Option 3 alloy 7.83 1.00 The cost-to strength ratios favor is aluminum but cost may not be a major issue at the moment. The cost also favors aluminum alloy when comparing weight due to the ease of manufacturability. In this case we choose as it has the lowest cost of materials and this will save the long term cost of the project. Design optimization methodology Design Requirements- the design of brake pedal various parameters needs to be considered and they include; Dimensions – maximum length, width and height Weight – Safety Levels The scoring were rated using the following scale Relative performance rating Much worse than 1 Worse than 2 Same as 3 Better 4 Much better than 5 Rating Efficiency Weight Safety requirements Weight (%) rating weighted score rating Weighted score rating weighted score Reliability 15 4 0.6 4 0.6 3 0.45 Manufacturing cost 15 2 0.3 2 0.3 3 0.45 Maintenance and Repair 15 3 0.45 3 0.45 4 0.6 Efficiency 15 3 0.45 4 0.6 5 0.75 Occupant Protection 20 4 0.8 3 0.6 4 0.8 Durability 10 3 0.3 3 0.3 4 0.4 Total score 3.2 3.85 3.55 Action reject Accept reject This defines the source of energy and t is distributed within the system to make the brake pedals operate. The following are designs available for the system to operate. The rate of movement is to be controlled by hand with the help of now extraneous booms or electronic slew rate monitors and controls. The system proposed above is in use in many engineering section however, the cost of manufacture and maintenance is inhibitive. It requires large space to be effective and efficient. The next power drive system under consideration is breaking system This option is one of the best in terms of maintenance, purchase, installation and usage. It is uses small space and provides effective movement and good performance compared to the other designs. The best advantage this design provides is that it has a variable speed control with the help of the brake pedals. Preliminary analysis Safety is main factor in the design of the braking system. This is because it involves human contact and if not given importance could be very risky. The second factor to be considered is the mechanism being used to braking system from one place to another. This is also important because it will determine how compact the space is, how easily it is operated etc. When designing various considerations was taken into consideration, one of the considerations was safety factor. The final product was required to have plant edges to avoid injury to the users. They were also required to be of reasonable size to avoid the straining of drivers when they are using them. The pedal part should be wide as well as have enough stepping treads for the driver to step on without slipping. There must be a distance between the pedals to enable the driver have proper usage. Conclusion In the production, design, modeling and simulation of brake pedal various methods and testing are done to ensure that it works at the minimum without any effect. The designed brake pedal was a simple model and was done successfully. The pictorial representation of the model parts has been made. The designed brake pedal has the capacity to withstand modulus of elasticity of 14200MPa has yield strength of 220MPa. The density of aluminum was 27000kilograms/m3 and elongation of 8%. References Dym, C. L. & Little, P., 1999. Engineering Design: A Project-Based Introduction, John Wiley, New York. Ertas, A. & Jones, J. C., 1996. The Engineering Design Process, John Wiley and Sons, NewYork, 1996. Hyman, B., 1999. Fundamental of Engineering Design. New Jersey: Prentice Hall, Lumsdaine, E., Lumsdaine, M. & Shelnutt, J. W., 2008 Creative Problem Solving and Engineering Design. New York: McGraw-Hill, Inc.. Read More