Analysis Of Materials Used For A Car Jack

Activity 1
Choose a product by looking around you at home, workplace, in your car, or anywhere else.
Typical examples include a part or parts of your home’s vacuum cleaner, your bicycle’s sprocket
and chain mechanism, your car’s wheel rim, etc. It is desirable to choose a product where a
change of material would result in an improvement such as preventing material failure,
improving efficiency, improving safety, etc. Then identify and perform an analysis of the
suitability of the material(s) used in the product. In this activity you may find useful Appendix B
(Properties of Selected Materials) and Appendix C (Costs and relative Costs for Selected
Engineering Materials) of reference 2 which can be found in the reserve collection of ECU
library.

Activity 2
Try to find and propose substitute materials which could lead to improvement(s), if any. You
are required to provide adequate reasons and justification for your selection of substitute
materials and explain the sort of improvement expected if the change of material is made. In
some instances a possible outcome could be “no change in the material(s) is recommended,”
however, you should be able to properly justify this. In this activity you need to study assigned
readings of Lecture 6 on the selection of materials – particularly substitute materials selection
examples – and also Ashby’s materials selection charts published in reference 4. The latter
reference can also be found in the reserve collection of ECU library. Take into consideration
factors such as
? performance,
? cost or relative cost,
? safety,
? manufacturing method, and
? environmental issues.

Activity 3
This is an optional activity. If a reasonable change of material is suggested then contact the
manufacturer and talk to them about your research and your suggestion on change of material;
and the sort of improvements that may be achieved. You need to follow this up and it is often
hard to get in touch with industries, however, it worth trying, and this may result in your
connection to the industry.

Types of Car Jacks

ACTIVITY 1:

Identification and analysis of Material

A car jack is a mechanical device that helps in lifting up a vehicle whenever a tire change is required. Car jacks are of different types: hydraulic jacks, scissor jacks and sometimes electric jacks. This device utilizes mechanical effort to lift the vehicle using human force although the force is greatly reduced as compared to when the device is not in use. The car jack employs a screw thread mechanism that is rotated to lift a vehicle. The tension due on the screw thread enacts a compression force that initiates a lift. The threading magnifies the human effort from the lever which is subsequently translated to the screw thread and to the load platform to perform a great work of lifting heavy loads (Yousef Haik, 2015). Car jacks are very useful especially during emergencies like getting a flat tire in the middle of a desert or a deserted place and this facilitates the repairs. For the car jacks to perform well, there is a need for the manufacturer to take into considerations the strength of the material to use, its durability and most importantly the cost of the material. In my report, I have analyzed and re-evaluated the sustainability of the materials used in designing and manufacturing a car jack, considering the suitability of the material in performing its tasks and the cost that was used in coming up with the device. Also in the report is further recommendations that would improve research and design processes

The analysis of materials used for a car jack

A typical car jack is shown below:

The table below shows a parts list for the car jack

Selection of the materials

During the design process, the selection of the materials to be used is a fundamental basic that should not be taken for granted. The process is design guided since it involves the properties of the component required that gives rise to the most suitable material for long-term use and capable of performing in the circumstances given. The selection of the materials involve three main steps. First is to collect and adopt all available materials that are thought possible to be used in the design. Secondly, the materials are brought to scrutiny where they are selected according to the properties of the component required and most importantly taking into consideration the function it will perform. The last step involves picking the best material out of the scrutinized materials. The best material should be favourable in all aspects from the cost of the materials to the mechanical properties involved (James C. Gerdeen, 2011).

Factors Involved in Material Selection

Some of the regularly used materials in engineering include aluminum, copper, plastics, cast iron, and the most common steel with all of their respective alloys. In coming up with a screw jack, it is therefore of necessity to find suitable materials. The material selection is majorly dependable on the following factors:

The ability of the material to withstand abrasive wear

Wear of materials usually occurs due to the constant rubbing of the materials against each other mostly in parts that are in relative motion (Crispin Hales, 2011). In the selection of a screw jack material, it is of great gain to select those materials that would resist abrasive wear or those that wear out slowly.

The strength of the material

Selection of a car jack material requires one to put into consideration a material with greater yield stress. The material should be able to sustain heavy loads without collapsing. The density of the material should also be low so that a screw shaft with greater strength can be realized. It is therefore important to select a material that has a high strength. Some of the strength properties include:

• The elastic limit: This is the power required to deliver lasting disfigurement.
• Yield point: This alludes to the level of the heap at which strain proceeds at a consistent pressure.
• Yield Strength: The measure of pliable power required to worthwhile motivation a very much characterized changeless disfigurement in a material.
• Ultimate Tensile Strength (UTS): This is the most extreme quality of material and compares to the greatest load pressure a basic part can withstand before crack.
• Compressive Strength: This is the capacity of a material to oppose a step by step connected the compressive load

Resistance to collapsing

The material that is used to make the screw should be somewhat elastic and show deflection characteristics. In case of a heavy load, the screw should be able to withstand it even when the critical load limit is exceeded without collapsing (Kutz, 2002).

The property of heat transmission

Heat is normally produced due to friction from the rubbing parts. In our case, the nut and screw are in motion, and therefore heat is likely to be generated. The materials used in these parts should be able to function properly even at high temperatures without deforming or changing their unique properties (Anatoly Lanin, 2008).

Cost and availability of the materials

The raw materials used accounts for more than 50% of the total cost of the end product of a given commodity. To manufacture affordable car jacks, the selection of the materials depending on the cost is vital as it counts at the end of the total production cost. The cost is also dependant on the availability of the materials in or near the manufacturing site. The further the materials are the more expensive it becomes in producing. Therefore, before choosing the material, the cost, availability, and affordability need to be considered (Ashby, 2010).

Other costs to be considered include the cost of work required to create the completed item from that material, cost of the materials used for processing, service cost acquired and tool maintenance cost.

Materials Used in Designing a Car Jack

Rigidity

This is the process by which a material resists bend even when a force is being applied. Its predefined by the versatile modulus of a material. Modulus of flexibility is the proportion of the connected pressure to the relating strain in the versatile furthest reaches of a material. Rigidity is dependent on the elastic modulus value; the greater value adds more rigidity to the material.

In engineering, material selection advances in the following order:

1. Translation of plan prerequisites into particulars for a material.
2. Eliminating the materials with properties that do not match with the particulars keeping in mind the end goal to leave just the best material.
3. Listing of the remaining materials to pick the material with the best property.
4. Employing required data to at long last land at the decision of material to be utilized.

The initial three stages include scientific examination, utilization of different diagrams and charts of a particular property, for example, particular quality, wear protection, clasping protection and reasonableness (Marshek, 2012). The materials are looked at, positioned according to the files of legitimacy, and accessible supporting data is utilized to achieve an ultimate conclusion

ACTIVITY 2:

Carjack parts and their corresponding selected materials

The objective of material determination is to concoct a proper material that best meets the plan prerequisites. The approach is to recognize the association between useful prerequisites and the material properties to enable us to diminish the number of hopeful materials from which to choose from.

Here is a detailed material selection information on each part of the car jack: The screw experiences bending moment, compressive force and torsional moment. For these forces to be overcome, a square type of thread is used which is known to be stronger compared to other types of thread. The square thread is most preferred because of the self-locking feature, and also it has high efficiency. Square threads are made using a lathe machine with a single point cutting tool. The material used in making screw is steel since steel has a high resistance to corrosion and also steel has a higher yielding strength. Majority of the manufacturers prefer carbon steel since its workability is excellent. Also, carbon steels can be modified easily to produce the desired strength properties (Frederic P. Miller, 2010). Compared to other types of materials, carbon steel is cheaper. The heat treatment of the plain carbon steels is possible and can result in modifying the steel properties such as strength and hardness. Some properties of the material used in the screw are listed below:

1. The material is of 0.30C
2. The selected material is classified under the British Standard specification BS 970 080M30

• The material is hardened and tempered

1. The maximum section size of the material is 63
2. The yield strength is 385 MPa
3. The tensile strength ranges from 550MPa to 700MPa

• The elongation is 13%
• Finally, the hardness number ranges from 152HB to 207HB

1.The body

The body comprises of the lifting members, connecting members, the base and load platform. They are made in a conical shape to allow room for easy assembling of the screw and the nut. All these members work together to provide support to the screw jack, and the materials used give the body strength to accommodate the compressive forces it experiences.

Specifications of Parts and Material Used

The body parts are cast during manufacturing for them to perform their full function, and hence the material suitable is grey cast iron. It is mostly preferred because it is readily available and also it is cheaper compared to other metals. The reduced cost is largely due to its ability to be modified easily into different shapes, and hence the machining costs are reduced. Cast iron is advantageous in the design of car jack because of its most suitable characteristic of having a high compressive strength (Frederic P. Miller, 2010). The cast iron mechanical properties are enlisted below:

1. Cast iron has a tensile strength of 220MPa
2. Cast iron has an endurance limit of 96MPa

• Its Young’s modulus ranges from 89GPa to114GPa

1. Cast iron’s shear strength is 284MPa
2. Cast iron has a modulus of rigidity ranging from 36GPa to 45GPa
3. Cast iron has a high compressive strength of 766MPa

• Finally, it has a hardness number of 196HB

2.The Nut

The nut is the most crucial part of the car jack when it comes to its material selection since there is a constant motion when it runs through the screw and hence friction occurs that leads to wear and tear of the nut. A softer material is recommended when designing a nut for the car jack. Phosphor bronze is, therefore, the most suitable material to be used as a nut. It is an alloy of copper containing an insignificant percentage of lead. Phosphor bronze is advantageous because its coefficient of friction is low, its tensile strength is high and also it does not corrode easily (William D. Callister, 2010) .

The bronze used contains 0.2% of phosphor which is responsible for the high tensile strength. The following properties are attributed to the bronze used to manufacture the nut:

1. The bronze has a tensile strength of 125MPa
2. The bronze’s compression strength is 150MPa

• The bronze has a yield stress of 105MPa in shear

1. It also has a safe bearing pressure of 15MPa going by a rubbing speed of 3m/s
2. Its ultimate tensile strength is 190MPa
3. The bronze’s coefficient of friction is 0.1

3.The lock nut and set screw

The material required to make the set screw should be of high rigidity because primarily the set screw is meant to stop motion between the screw and the nut. The washer and lock nut provide the area experiencing the action force. They both unify the force and hence enhance less strain in the screw thread (Richard G. Budynas, 2015). Plain carbon steel is used as the most suitable material for these parts because its properties are the same as of the screw.

All the above design specifications are arrived at from calculation and physical testing of the components by the manufacturers. The calculations involved include searching for the tensile strengths, compression strengths, the yield stresses and the young’s modulus of elasticity. Before the screw jack is made, necessary tests have been performed to aid in the selection of the most suitable material.

In the analysis of the materials used in designing various parts of the car jack, there was no change of material necessary for the existing designs. The materials are chosen put into consideration the material selection procedure, and the best materials were chosen for different parts according to their functionality. They took into consideration the availability of the materials; the cost was minimized, the physical and mechanical properties were considered before selection of the materials. However, there may be substitutes to the materials of the components, but it is highly discouraged to use the substitutes because even if they have the qualities asserted for, they may not be the best and it might lead to failure of the whole system. Some substitutes may have difficulty in manufacturing, and hence the cost may hike as a result. The fundamental objective when manufacturing should be cutting on unnecessary costs and this can be achieved in making the right selection of the materials.

Conclusion:

The selection of materials is key to any manufacturing process. It involves three stages that have to be followed for a successive choice of the most suitable material for the design. All the materials are collected depending on the availability then there is a process of eliminating the unwanted materials depending on the properties required for the design and lastly the ranking of the materials to pick the most suitable material. Car jack’s components passed through the selection process, and the most suitable materials were selected giving in to all demands of the purpose. The common materials used in the manufacture of the car jack include plain carbon steel, bronze, and cast iron. All the materials differ with the task they perform, and hence the material selection process prevents material failure thereby increasing the efficiency of the product. The car jack materials are easily accessible, they are less costly and their properties are reliable in the sense that the selected materials function perfectly as designed. Material failure is minimizes in that process and hence efficiency is increased.

Recommendations:

1. There should be precise documentation of the costs of all materials to ease research and improve design precision.
2. Tests should be done for different alloys to give rise to many substitutes that would possibly reduce further the costs of the materials and improve quality of the services.
3. A program should be initiated that is set to allow students access the industry to boost their practical knowledge of material selections.
4. Students should be encouraged to come up with their own designs of materials and also should be provided with necessary requirements to be able to test the materials designed for specific components.

References:

Anatoly Lanin, I. F. (2008). Thermal Stress Resistance of Materials. Berlin: Springer Science & Business Media.

Ashby, M. F. (2010). Materials Selection in Mechanical Design. Oxford: Butterworth-Heinemann.

Class Professor. (2018). Lecture 6 notes. Australia.

Crispin Hales, S. G. (2011). Managing Engineering Design. Berlin: Springer Science & Business Media.

Frederic P. Miller, A. F. (2010). Carbon Steel: Steel, Carbon, Stainless Steel, Ductility, Welding, Interstitial Defect, Bravais Lattice, Cubic Crystal System, Dislocation, Heat Treatment, Work Hardening, Hot Working. San Carlos: Alphascript Publishing.

James C. Gerdeen, P. P. (2011). Engineering Design with Polymers and Composites, Second Edition. Florida: CRC Press.

Kutz, M. (2002). Handbook of Materials Selection. New Jersey: John Wiley & Sons.

Marshek, R. C. (2012). Fundamentals of Machine Design Components. Fifth Edition. New Jersey: John Wiley & Sons Inc. .

Richard G. Budynas, R. G. (2015). Shigley's Mechanical Engineering Design. New York: McGraw-Hill Education.

William D. Callister, D. G. (2010). Materials Science and Engineering: An Introduction. New Jersey: John Wiley & Sons.

Yousef Haik, S. S. (2015). Engineering Design Process. Boston: Cengage Learning.