Group 21 2012 Gate 3 - Revision history

MAE 277 2012 - Group 21: /* Challenges */

2012-12-14T06:09:28Z

Challenges

MAE 277 2012 - Group 21: /* Analysis Process */

2012-12-14T06:05:06Z

Analysis Process

MAE 277 2012 - Group 21: /* Introduction and Justification */

2012-12-14T06:03:22Z

Introduction and Justification

MAE 277 2012 - Group 21: /* Product Analysis */

2012-12-14T06:02:59Z

Product Analysis

MAE 277 2012 - Group 21: /* Cause for Corrective Action */

2012-12-14T06:00:48Z

Cause for Corrective Action

MAE 277 2012 - Group 21: /* Table 1: Weekly Schedule */

2012-12-14T03:35:04Z

Table 1: Weekly Schedule

Show changes

MAE 277 2012 - Group 21: /* Monday Meeting Minutes */

2012-12-14T03:34:05Z

Monday Meeting Minutes

MAE 277 2012 - Group 21: /* References' */

2012-12-14T02:49:32Z

References'

MAE 277 2012 - Group 21: /* Engineering Analysis */

2012-12-14T02:49:08Z

Engineering Analysis

MAE 277 2012 - Group 21 at 02:38, 14 December 2012

2012-12-14T02:38:56Z

Show changes

@@ Line 27: / Line 27: @@
 *We have set up google docs account so all material being worked on will be available to each group member.
 *We have meetings about once a week and the minutes can be found in the table below.
-**After the due date of this gate, the updated meeting minutes and table will be found on gate 4 with updated information in Table 1.
 '''''Wiki Organization '''''

@@ Line 798: / Line 798: @@
 The frame is a key component of the bicycle. It is the backbone, which supports and connects all of the other parts. It also contributes to a large percentage of the bicycle’s weight, which is a huge factor in a bicycle’s performance. Lastly, the frame plays a big part in determining the final cost of the product since different frame materials are more expensive than others. To a consumer, those are the two biggest concerns: performance and cost. For these reasons, it is a component that would require a lot of engineering analysis during the design and testing stages of the design process.
 ===''Analysis Process''===
-===='''Problem Statement'''====
 Engineers first need to determine the problem to be solved. In this case, the problem is deciding the best material to be used in the bicycle frame. To begin, certain questions need to be asked. Who is the target audience? Are they a casual or competitive rider? Are they male or female? What is their weight and height range? They also need to know what the factors are that decide performance and make one material better than other. What are the equations that are used to determine that?
-===='''Diagram'''====
 First we must understand the loads that the bicycle frame is subjected to and must be able to withstand. The following system diagram is helpful to visualize it:
 [[File:diagram.gif|frame|center|Force Diagram for the Bicycle. Referenced from http://earth911.com/wp-content/uploads/2008/10/bicycle.jpg]]
@@ Line 806: / Line 810: @@
 There are two main factors, stiffness and strength, that determine how well the frame is able to support these forces. These two factors, along with the main design factor, weight, all affect the general performance of the bicycle and must be taken into consideration during the design process. The ideal frame has a high stiffness so that it can support the mentioned loads with minimal elastic deflection (bending). It has a high strength to avoid cracking and fatigue due to impacts and rough surfaces, and it has a low weight so that it can accelerate and go uphill faster (“aluMATTER”).
-===='''Assumptions'''====
+'''Assumptions'''
 Depending on the audience, different assumptions can be made. For example, if the audience is a child, it can be assumed that cost will be a big factor, since children grow out of bicycles quickly and need to replace them more often than an adult. It can also be assumed that the child won’t take care of it very well, and get in a lot of damaging collisions and impacts, therefore it will also need to be strong enough to withstand those impacts. This is why knowing the audience is a big part in analysis, and is one of the first questions asked.
-===='''Equations'''====
+'''Equations'''
 Different materials perform better than others in tests for these factors.
 We must also take into account the fact that some materials weigh more than others, so stiffness and strength need to be based on a strength-to-weight ratio and a stiffness-to-weight ratio. For example, aluminum weighs less than steel, but a tube of aluminum is less stiff than the same exact same size tube made of steel. Aluminum can be stiffer than steel though if the diameter of the aluminum tubing is increased. Of course this would increase the weight, but compared to the steel, it already weighs a lot less, so the extra weight is allowable (“Ultracycling”). For this reason weight is taken into account in stiffness and strength by dividing by the material density. The following equations are used to determine the specific stiffness and specific strength for different materials (“aluMATTER”):
@@ Line 817: / Line 823: @@
 [[File:deflection.gif|center|frame|Deflection equation used for analysis]]
-===='''Calculations'''====
+'''Calculations'''
 Using these equations, we can then calculate the values for different materials to see which ones will perform better. The specific stiffness and specific strength (fatigue resistance) for different materials common materials are plotted below. The materials highlighted in blue are materials that have been used in bicycle frames already (“aluMATTER”).
 [[File:pic2.gif|center|frame|Figure 1: Specific stiffness and specific strength plot. Referenced from http://aluminium.matter.org.uk/content/html/eng/default.asp?catid=89&pageid=2144417038]]
 '''''Figure 1: Specific Stiffness and Specific Strength Plot Analysis'''''
-===='''Solution Check'''====
+'''Solution Check'''
 This chart shows that carbon fiber reinforced plastic (CFRP) is the material that will provide the best performance as it has a high stiffness and strength (fatigue index) while also providing a minimal weight. This makes sense because CFRP is known to be very light and very strong, which is why it’s a great alternative to the common steel frames. Notice also that the metals all have roughly the same stiffness, but vary in strength, with titanium and magnesium being stronger than steel and aluminum, which makes sense if you think about common objects made from each of those materials.
-===='''Discussion'''====
 While CFRP is the better material, it is also very expensive. Steel on the other hand, is known for its strength but relatively low cost, which is why it’s still used widely in bicycles today. It would probably be the best material to be used in a bicycle aimed for children. Engineers will need to build different bicycles with different materials to satisfy a range of audiences. Engineering analysis is used to determine the best design for a specific audience, and what tradeoffs will need to be made to accommodate that audience. For example, a casual rider that uses a road bike will not care as much for performance and care more for cost, so in the analysis, the engineer will have to sacrifice performance for cost. The opposite can be true. A more competitive rider who cares most about speed and performance will want the best material and care less about cost. Bicycles targeted for that audience, will have a more expensive, yet better performing frame. The analysis process will need to be used to determine exactly what the audience is, and what kind of tradeoffs need to be made to satisfy them.

@@ Line 339: / Line 339: @@
 '''Component Function'''
 Here we will be talking about what components functions they perform, what flows they are associated with and what environment it functions in. We have discussed this concept for each component in Table 3.
 '''Component Form'''
 Here we will be talking about the geometry, material and appearance of the component. For geometry, the general shape, properties, how it influences the function of the component, weight, etc. For material, we will be talking about what the component is made of as well as manufacturing methods, which will include aesthetics. We have discussed this concept for each component in Table 3.
 '''Manufacturing Methods'''
 We will be specifying out manufacturing choices with evidence and conclusions coming from shape, material and GSEE factors. We have discussed this concept for each component in Table 3.
 '''Component Complexity'''
 ===''Table 3: Product Analysis''===

@@ Line 338: / Line 338: @@
 :::The brake cable is needed for the brake pad to create friction with the rim. Without the cable, the braking mechanism on this bike would not function. Another braking mechanism would need to be added, or the user would have to put down their feet to stop the bike. The braking cables allows the user to slow down and stop safely.
-===''Component Function''===
+'''Component Function'''
 Here we will be talking about what components functions they perform, what flows they are associated with and what environment it functions in. We have discussed this concept for each component in Table 3.
-===''Component Form''===
+'''Component Form'''
 Here we will be talking about the geometry, material and appearance of the component. For geometry, the general shape, properties, how it influences the function of the component, weight, etc. For material, we will be talking about what the component is made of as well as manufacturing methods, which will include aesthetics. We have discussed this concept for each component in Table 3.
-===''Manufacturing Methods''===
+'''Manufacturing Methods'''
 We will be specifying out manufacturing choices with evidence and conclusions coming from shape, material and GSEE factors. We have discussed this concept for each component in Table 3.
-===''Component Complexity''===
+'''Component Complexity'''
 We will define a meaningful scale to how complex our component is. We will also discuss the complex the connections. We have discussed this concept for each component in Table 3.

@@ Line 14: / Line 14: @@
 *Attendence
-==== '''Challenges That Have Been Addressed'''====
+'''Challenges That Have Been Addressed'''
-===== Communication=====
 The main communication problems were as follows:
@@ Line 28: / Line 29: @@
 **After the due date of this gate, the updated meeting minutes and table will be found on gate 4 with updated information in Table 1.
-=====Wiki Organization =====
+'''''Wiki Organization '''''
 In our first gate, we were marked down highly because of our disorganization of the wiki page. We have changed roles and Tiffany has taken over the wiki programming. Comments from the grading rubric have been taken into consideration while this gate was being produced.
-==== '''Unresolved Challenges'''====
+'''Unresolved Challenges'''
-=====Attendance =====
 A recurring problem we have been having as a group is the poor attendance not only to the weekly meetings, but to class as well. To solve this problem, we attempted to have a meeting with the professors that not everyone in the group attended. We address this as an unresolved challenge even through we have attempted to solve this problem a few times before.
 We address this problem by sending emails to the professors, making them aware of the issues we are having. The emails contain all information covered in our meetings as well as who attended, who did not, the agenda of the meeting, time, place, etc. If needed the group member will be spoken to by the professors if they fail to meet the needs of the group.
-===='''Future Challenges'''====
+'''Future Challenges'''
 Some challenges we foresee are:
 *Group members still not attending class and/or meetings.

@@ Line 707: / Line 707: @@
 |style="background-color: #fe0000;"|
 |}
 =====Wiki Organization =====

@@ Line 1,539: / Line 1,539: @@
 What the engineer chooses for the final design all depends on the targeted audience. For example, with our product, the targeted audience seems to be casual riders that want a low cost bicycle and don’t seem to care too much about performance. This can be concluded by the fact that the frame is made of steel, which doesn’t perform as well as other materials, but is relatively cheap. It can also be reasonably concluded that it is targeted to female consumers since the color of the frame is baby blue. These are all factors that an engineer needs to take into account for analysis during the design process. Tradeoffs will always have to be made in order to satisfy different audiences.
-===''References'''===
+===''References''===
 '''“aluMATTER.” '''