APPENDIX B-2 2014 FSAE™ IMPACT ATTENUATOR DATA REPORT – Page 1 of 3

This form must be completed and submitted by all teams no later than the date specified in the Action Deadlines on specific event website. The FSAE Technical Committee will review all submissions which deviate from the FSAE® rules and reply with a decision about the requested deviation. All requests will have a confirmation of receipt sent to the team. Impact Attenuator Data (IAD) and supporting calculations must be submitted electronically in Adobe Acrobat Format (*.pdf). The submissions must be named as follows: schoolname_IAD.pdf using the complete school name. Submit the IAD report as instructed on the event website. For Michigan and California events submit through fsaeonline.com. *In the event that the FSAE Technical Committee requests additional information or calculations, teams have one week from the date of the request to submit the requested information or ask for a deadline extension. University Name: California State University, Northridge Car Number(s) & Event(s): 31 Team Contact: Luiz Oliveira E-mail Address: luiz.oliveira.423@my.csun.edu Faculty Advisor: __Dr. Stewart Prince_____ E-mail Address: sprince@csun.edu !!!!!!!!!!!!

Material(s) Used 5.2-1/4”-.0025N-3003 Aluminum Honeycomb; .08” 4130 steel plate Description of form/shape 8” x 6.25” x 9” Aluminum Honeycomb IA to Anti-Intrusion Plate mounting method

3M Scotch-Weld AF 126 .06wt film adhesive

Anti-Intrusion Plate to Front Bulkhead mounting method

Weld

Peak deceleration (<= 40 g's) 18.1 g’s Average deceleration (<= 20 g's) 16.6 g’s

Confirm that the attenuator contains the minimum volume 200mm wide x 100mm high x 200mm long

Figure 1: Force-Displacement Curve

ATTACH PROOF OF EQUIVALENCY TECHNICAL COMMITTEE DECISION/COMMENTS

_______________________________________________________________________________________ Approved by__________________________________________ Date_____________ NOTE: THIS FORM AND THE APPROVED COPY OF THE SUBMISSION MUST BE PRESENTED AT TECHNICAL INSPECTION AT EVERY FORMULA SAE EVENT ENTERED

0

10000

20000

30000

40000

50000

60000

0 25 50 75 100 125 150 175 200

Forc

e, F

(N)

Displacement, x (mm)

Force v. Displacement

!!

APPENDIX B-2 2013 FSAE™ IMPACT ATTENUATOR DATA REPORT – Page 2 of 3

University Name: California State University, Northridge Car Number(s) & Event(s): ______31_______

Figure 2: Energy-Displacement Curve

Figure 3: Attenuator as Constructed Figure 4: Attenuator after Impact

Energy Absorbed (J): Must be >= 7350 J

8746.8 Joules Vehicle includes front wing in front of front bulkhead?

No

IA Crushed Displacement (mm):

179 mm Wing structure included in test?

No

IA Post Crush Displacement - demonstrating any return (mm):

175 mm Test Type: (e.g. barrier test, drop test, quasi-static crush)

Quasi-static crush

Anti-Intrusion Plate Deformation (mm)

6.1 mm Test Site: (must be from approved test site list on website for dynamic tests)

CSUN Applied Mechanics Lab

APPENDIX B-2 2013 FSAE™ IMPACT ATTENTUATOR DATA REPORT – Page 3 of 3

University Name: California State University, Northridge Car Number(s) & Event(s): ______ 31_______

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

10000

0 25 50 75 100 125 150 175 200

Ene

rgy,

Ea (

J)

Displacement, x (mm)

Energy v. Displacement

Figure 5: Design Drawings

Length (fore/aft direction): 228.6 mm (>=200mm) Width (lateral direction): 203.2 mm (>=200mm) Height (vertical direction): 158.75 mm (>=100mm) Attenuator is at least 200mm wide by 100mm high for at least 200mm: Yes Attach additional information below this point and/or on additional sheets

Test schematic, photos of test, design report including reasons for selection and advantages/disadvantages, etc. Additional information shall be kept concise and relevant.!

!

California State University, Northridge2013-2014 Formula SAE Team - Car # 31

Impact Attenuator Report

Abstract

The objective of this document is to demonstrate our full comprehension of the energy absorbtion system. The following report willstep through the interpretation of the impact attenuator test results, and will show how we used the data from quasistatic compressiontesting to obtain values for average decceleration, maximum decceleration, and total energy absorbed.

I. Nomenclature

m Vehicle mass (300 kg), kgg Acceleration due to gravity, m/s2

n # of data pointsFi, i = 1, 2, ...n Force measured, NFav Average Force, NFmax Maximum Force, Nxi, i = 1, 2, ...n Displacement measured, mAav Average Deceleration, g’sAmax Maximum Deceleration, g’sEa Total Energy Absorbed, J

II. Results & Analysis

Excel and VBA were used to perform the calculations.

The average force of all the data points (Plotted in Figure1) is:

Fav =

n∑

i=1Fi

n

⇒ Fav = 48938.7 N

The maximum of all the force data points is:

Fmax = 53321.3 N

The average deceleration must be less than 20 g’s. It iscalculated by:

Aav =Favmg

=48938.7

(300)(9.81)

∴ Aav = 16.6 g’s ≤ 20 g’s

The maximum deceleration must be less than 40 g’s. It iscalculated by:

Amax =Fmaxmg

=53321.3

(300)(9.81)

∴ Amax = 18.1 g’s ≤ 40 g’s

The energy absorbed by the impact attenuator as it de-forms is the area under the force-displacement curve shownin Figure 1. The impact attenuator needs to absorb at least7350 J. So we have to ensure that:

Ea =� xn

x1Fdx ≥ 7350 J

To find the area under the data points, the TrapezoidalRule was used. So the area under the set of points thenbecomes:

� xn

x1Fdx ≈

n−1

∑i=1

(xi+1 − xi)

�Fi+1 + Fi

2

�

� xn

x1Fdx = 8746.8 J

∴ Ea = 8746.8 J ≥ 7350 J

III. Summary of Results

Description Value UnitsAverage Deceleration 16.6 g’s

Maximum Deceleration 18.1 g’sTotal Energy Absorbed 8746.8 J