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mech engg paraphrasing


Open Posted By: jamesanderson Date: 16/08/2020 Academic Level: High School Paper Type: Homework Writing

below are two files attached ,the doc file is the one to be fully paraphrased , even i want new excel tables with same numbers thats why i am attaching excel file as well which u can use


Category: Arts & Education Subjects: Art Deadline: 24 Hours Budget: $60 - $90 Pages: 2-3 Pages (Short Assignment)

Attachment 1

Sheet1

Dynamic Analysis of a Spring
Problem Information & A Priori Decisions General Constraints
Material: Phosphor Bronze (B159) Surface Treatment: Unpeened Ls ≤ 1 in
Dyanmic Load: End Treatment: Squared & Ground L0 ≤ 4 in
Min 4 lbf Robust Linearity: 15% fn ≥ 130 Hz
Max 18 lbf Set: As Wound 3 ≤ Na ≤ 15
Frequency: 6.5 Hz Fatigue: 4 ≤ C ≤ 12
Deflection: Min 1.5 (L0)cr > L0
Min 0.5 in FoS: 1.5
Max 2 in Gamma: 0.32 lbf/in^3
Max Height: 1 in G: 6 Mpsi
Free Length: 4 in E: 15 Mpsi
Sut= A/d^m fom: 8
Ssu= Sut
Ssy= .85Sut
Table 10-4 Eq. 10-14 Eq. 10-28 Eq. 10-13 D-d D+d
d (in) D (in) Fmax (lbf) Fmin (lbf) Fa (lbf) Fm (lbf) k m A Sut (ksi) Ssu (ksi) Ssy (ksi) Ssa (ksi) Alpha (psi) Beta (psi) C Fs (lbf) Na (turns) Nt (turns) Ls (in) L0 (in) ID (in) OD (in) ys (in) L0crit (in) KB W (lbf) fn (Hz) tau a (psi) tau m (psi) tau s (psi) nf ns fom
0.075 0.44 18 4 7 11 9 0.064 110 129.834 129.834 110.359 35 23333.33 3168.95 5.932 20.7 29.939 31.939 2.395 4.70 0.37 0.52 2.3 2.34 1.241 0.059 121.164 23333.33 36666.67 69000 1.5 1.60 -1.578
0.078 0.51 18 4 7 11 9 0.064 110 129.509 129.509 110.082 35 23333.33 2929.87 6.552 20.7 23.106 25.106 1.958 4.26 0.43 0.59 2.3 2.69 1.215 0.057 123.734 23333.33 36666.67 69000 1.5 1.60 -1.541
0.08 0.56 18 4 7 11 9 0.064 110 129.299 129.299 109.904 35 23333.33 2785.21 6.977 20.7 19.629 21.629 1.730 4.03 0.48 0.64 2.3 2.94 1.201 0.055 125.248 23333.33 36666.67 69000 1.5 1.59 -1.525
0.085 0.69 18 4 7 11 9 0.064 110 128.798 128.798 109.478 35 23333.33 2467.18 8.080 20.7 13.430 15.430 1.312 3.61 0.60 0.77 2.3 3.61 1.171 0.053 128.479 23333.33 36666.67 69000 1.5 1.59 -1.511
0.09 0.83 18 4 7 11 9 0.064 110 128.328 128.328 109.079 35 23333.33 2200.66 9.242 20.7 9.499 11.499 1.035 3.33 0.74 0.92 2.3 4.38 1.147 0.051 131.094 23333.33 36666.67 69000 1.5 1.58 -1.529
0.095 0.99 18 4 7 11 9 0.064 110 127.885 127.885 108.702 35 23333.33 1975.11 10.467 20.7 6.903 8.903 0.846 3.15 0.90 1.09 2.3 5.23 1.129 0.049 133.249 23333.33 36666.67 69000 1.5 1.58 -1.577
0.105 1.38 18 4 7 11 9 0.064 110 127.068 127.068 108.008 35 23333.33 1616.81 13.106 20.7 3.887 5.887 0.618 2.92 1.27 1.48 2.3 7.24 1.101 0.047 136.573 23333.33 36666.67 69000 1.5 1.57 -1.763
0.112 1.69 18 4 7 11 9 0.064 110 126.544 126.544 107.563 35 23333.33 1421.03 15.105 20.7 2.708 4.708 0.527 2.83 1.58 1.80 2.3 8.90 1.087 0.045 138.343 23333.33 36666.67 69000 1.5 1.56 -1.972

Sheet2

Attachment 2

C:\Users\ehaffner\Documents\Courses\WNE_long_4_clr.jpg

TO:

FROM:

SUBJECT: Design Project 3–DOME–Design of a Helical Spring under Dynamic Loading

DATE:

Executive Summary

A Phosphor-bronze (B159) helical compression spring will be designed with infinite life that could sustain a fluctuating dynamic load that varies from 4 to 18 lbf at a frequency of 6.5 Hz [1]. The deflection of the spring varies from 0.5 to 2 inches [1]. Due to an assembly considerations, the solid height must not exceed 1.0 inches and the free length cannot be more than 4.0 inches [1]. The spring-maker has certain sizes of wires in stock: 0.075, 0.078, 0.080, 0.085, 0.090, 0.095, 0.105, and 0.112 inches [1]. The spring is required to be an as wound, un-peened spring that has been squared and ground. Calculations were performed for all available wire sizes in this material using equations, tables, figures, and examples provided in the 10th edition of Shigley’s Mechanical Engineering Design textbook [2]. The calculation outcomes were then compared to the failure criteria that could be shown in Table 1. Red highlighted values in Table 2 represents the failure spots where the outcomes have not met the design criteria.

Table 1: Table of failure criteria

Failure Criteria

4

C

12

3

Na

15

Ls

1

Lo

4

(Lo)cr

>

Lo

fn

130

The calculation outcomes verified the size of the wire that should be used, which is 0.095 inches as shown in Table 2. The calculated index of the designed spring (C) was 10.46 which lied under the given range between 4 and 12. The number of active coils (Na) for the wire size of 0.095 was calculated to be 6.9 turns, which is within the acceptable range of 3 to 15 turns. The solid length of the spring (Ls) was founded to be 0.85 inches and is under the required 1 inch maximum. The free length (Lo) was to be 3.15 inches which is under the 4 inches maximum of free length. The critical free length (Lo)crwas larger than the calculated free length with a value of 5.23 inches. The factor safety for both fatigue (nf) and solid height (ns) were 1.5 or larger as indicated. The designed spring has a natural frequency of 133.3 which is significantly greater in comparison to the operating of 6.5 Hz and is larger than the required criteria of 130 Hz. The wire of 0.095 only failed in the natural frequency unlike the others where they failed in more than one criteria. The calculation concluded that the wire size of 0.095 is the optimal one for this material and the design constraints. Sample of a hand calculations will be attached in Appendix A

Table 2: Table shows the wire sizes along with the optimal and the failure spots.

References:

[1]Mindek, Richard B., ME 425 Design of Machine Elements –Final Design Project, Western New England University, 2015

[2] Budynas, Richard G., Nisbett, J. Keith, Shigley’s Mechanical Engineering Design, 10th ed., McGraw-Hill, New York, 2015

Appendix A

Wire Size0.0750.0780.0800.0850.0900.0950.1050.112

Mean Coil DiameterD (in)0.440.510.560.690.830.991.381.69

Inner DiameterID (in)0.370.430.480.600.740.901.271.58

Outer DiameterOD (in)0.520.590.640.770.921.091.481.80

Spring IndexC5.936.556.988.089.2410.4713.1115.10

Number of Active CoilsNa (turns)29.9423.1119.6313.439.506.903.892.71

Solid LengthLs (in)2.401.961.731.311.030.850.620.53

Free LengthLo (in)4.704.264.033.613.333.152.922.83

Critical Length(Lo)cr (in)2.342.692.943.614.385.237.248.90

Fatigue Factor of Safetynf1.501.501.501.501.501.501.501.50

Solid Height Factor of Safetyns1.601.601.591.591.581.581.571.56

Natural Frequencyfn121.16123.73125.25128.48131.09133.25136.57138.34

fom-1.58-1.54-1.53-1.51-1.53-1.58-1.76-1.97

d (in)