Design Report DFMEA & Validation Presentation

SAEINDIA organized Two day

Faculty Leadership Development Programme on 21st & 22nd June 2013 at Priyadarshini College of Engineering, Nagpur.

Baja Design Report, DFMEA & Validation Presentation Dr. K.C. Vora

BROAD CLASSIFICATION •CHASSIS AND ROLL CAGE

•SUSPENSION SYSTEM

•ENGINE AND TRANSMISSION

•BRAKES AND STEERING

Vehicle Configuration Four or more wheels wheels.. Capable of carrying single seated person 190. 190.5 cm (6’3”) tall and weighing 113 113..4 kg (250 pounds). pounds). Maximum vehicle width should be less than 64 64”” including tyres and maximum length should be less than 108 108””. It must possess all terrain capability. capability. It should have adequate ground clearance and traction. traction.

Typical Design Targets Top speed Approximate weight Ground clearance Wheel base Track width Turning radius

50km/hr 210kg 9-10” 56” 60” 8’

Different parts of vehicle • Engine/Air Filter/Silencer • Transmission/Clutch/Differential • Seat • Roll Cage • Body • Axle/Balancing Rods • Suspension • Tyres • Brakes • Steering • Fuel System • Safety • Asthetics/Colour • Spares • Manufacturing Kit/Tool Kit •Innovation

ENGINE BAJA SAEINDIA Competitions require use of Engine provided by Briggs & Stratton, USA of following specifications specifications:: 4 stroke airair-cooled 10 10hp hp OHV Intek Model 205432 305cc, 305 cc, 19 19..66 66Nm@ Nm@2800 2800rpm rpm 79..25 79 25mm mm bore, 61 61..67 67mm mm stroke, 8:1 compression ratio A governor restricts the maximum speed to 3800 rpm

POWERTRAIN

EXHAUST 8 Lombardini LGA 340 Briggs & Stratton Standard Muffler of Sagar Integrated Exhaust Industries with integrated system Catalytic Converter

Engine Crankshaft Key

Adapter Spacer Couple r

Fig. Modified coupler exploded view

PARAMETER

Fig. F.E. Analysis of adapter

VALUE

Max Equivalent Stress Max Shear Stress Max Deformation

97.8 MPa

Factor of Safety

4.54

176 MPa

0.06 mm Fig. Back pressure of Exhaust

Roll Cage Tubular frame to take the loading and protect the driver in a rollover. Roll cage must incorporate appropriate: Rear roll hoop (RRH) Lateral diagonal bracing (LDB) Roll hoop overhead members (RHO) Lower frame side members (LFS) Side impact members (SIM) Front bracing members (FBM) Fore aft bracing members (FAB) Lateral cross member (LC)

Helmet, Head Restraint, Firewall, FireFire-extinguisher, Safety Belt, Spares, Design report, Cost report and Insurance are mandatory.

Rear Roll Hoop (RRH) The rear roll hoop functions to separate the driver from the engine. The fire wall is mounted on the RRH. The driver seat may not protrude the plane of RRH. The RRH should also be 29 inch or greater at a height of 27 inch from the base of the driver’s seat.

Rear Roll Hoop Lateral Diagonal Bracing (LDB)

Lateral bracing for the Rear Roll Hoop will begin at a point along the vertical portion of the RRH within 12.7 cm (5 in) vertically of point BL or BR and extend diagonally to a point no farther than 12.7 cm (5 in) above point AR or AL.

Roll Hoop Overhead Member (RHO) The RHO shall be located above the driver’s seat by a minimum of 104. 104.1 cm (41 inches) inches).. Points C should be located forward of the driver’s seat by a minimum of 30. 30.5 cm (12 inches) inches)..

Lower Frame Side Member (LFS) Lower frame side members shall join the RRH and LC and extend to points forward of the driver’s heel to a front lateral cross member. member.

Side Impact Member (SIM) Side impact members shall join the RRH at points S and extend horizontally to points SF forward of the driver’s toes. The SIM should be between 8 to 12 inc as measured from the base of the driver’s seat. The driver body should not be in contact with the SIM members.

Front Bracing Member (FBM) Front bracing members shall join the RHO, the SIM and the LFS LFS.. The angle between the FBMUP and the vertical should be less than 45 degrees.. degrees

Rear Bracing Members. The Rear bracing acts as a cage carrying the engine and transmission box. The bracing should be fully triangulated.

FABRICATION

USE OF DESIGN SOFTWARES

PTC/ANSYS/ALTAIR SOFTWARES

Software design

Vehicle Dynamics Simulation Vehicle Data

Animation

Math Model Maneuver

Plots Road and Wind Road course, skidpad, grades, cross-slopes, split-mu, crosswind

Hill Climb Test At 20kmph

At 30kmph

At 40 kmph

MATERIAL SELECTION Steel members with at least equal bending stiffness and bending strength. The bending stiffness and bending strength have to be calculated about an axis that gives the lowest value. Bending stiffness is proportional by the EI product and bending strength is given by the value of SyI/c.

M.S. 1.25 O.D. 16gauge

Material Material for the frame and chassis 1018 Circular steel tubing with OD 2.5 cm (1 inch) & wall thickness of 3.05 mm (0.120 inch). Equivalent AIS 4130 or BIS 1875.

Dimensions Overall Length: 84 inches Wheel Base: 63.5 inches Track: Front 50 inches Rear 52 inches Overall Weight 300 kg (w/o Driver)

Rods are cut and welded for chassis. Pipe bending can be used as an alternate measure.

Aim should be to reduce excess weight without compromising any structural rigidity or the safety of the driver. Centre of gravity should be maintained as low as possible.

The body panels protects the drivers’ body and provides a suitable enclosure. Roll cage padding reduces the damage in case of impact.

Specifications Frame was manufactured to fit a seat that allowed for maximum driver comfort and safety, features consumers demand The swing arm requires the engine to be mounted rigidly to the frame, and out of the way from the traveling suspension. This causes the center of gravity to be moved higher, and creates much more sprung mass. Roll cage padding protects driver’s head from impact.

Body

IMPORTANT SUSPENSION VARIABLES

a0 CAMBER ANGLE VARIATION

DIRECTION OF SUSPENSION TRAVEL GROUND CLEARANCE

TRACK WIDTH

GENERAL OBJECTIVES The suspension system forms the link between the frame and the wheels. The suspension of the car prevents the shocks from the road to reach you. For All Terrain vehicles the suspension travel should be as much as possible. The links and the shockers should be strong enough to sustain various shocks and fatigue resistant. The geometry should aid maximum tyretyre-road contact. There are many types systems available .

IMPORTANT DESIGN CONSIDERATIONS

The ground clearance should be optimum. The track width may be kept as much as possible but within the limits specified in the rules. Being the main features of all terrain vehicles, the wheel travel should be as much as possible. The camber variation should be as less as possible to improve the tyre tyre--ground contact which aids in traction..

Safety Features Safety is the primary consideration in the design of Baja SAE vehicles and the conduct of the competitions. Teams need to include safety considerations in all parts of their program. Roll cage A head restraint must be provided on the car to limit rearward motion of the head. In all cases, a minimum of 15.2 cm (6 inches) vertical clearance must be provided from the helmet top of the team’s tallest driver to the bottom of the roll cage top tubes or members. All drivers must be able to exit on either side of the vehicle within five (5) seconds.

A firewall between the cockpit and the engine and fuel tank compartment is mandatory mandatory.. It must cover the area between the lower and upper LC LC..

All drivers must use a minimum of a 4 strap restraint harness.

What is 4 - Point Harness belt? Harness Belt means a belt which is essentially a combination of lap strap and diagonal strap across the shoulder and chest. It is called as SS-type belt in ECE Regulation.

WEBBING LOOPS THROUGH THESE SLOTS FOR ADJUSTMENT

Specification

STANDARD FASTENER

1500 MM (ADJUSTER FULLY EXTENDED)

STANDARD FASTENER

STANDARD ADJUSTER

700 MM (ADJUSTER FULLY EXTENDED)

STANDARD FASTENER

STANDARD ADJUSTER

STANDARD STITCHING

STANDARD ADJUSTER

STANDARD BUCKLE

170 MM

STANDARD STITCHING

1500 MM (ADJUSTER FULLY EXTENDED)

STANDARD ADJUSTER

700 MM (ADJUSTER FULLY EXTENDED)

WEBBING LOOPS THROUGH THESE SLOTS FOR ADJUSTMENT

STANDARD FASTENER

HIGH ‘G’ CRASH TEST

To Validate belt assembly or a restraint system affecting the restraint of the occupant shall break and no buckles or locking system or displacement system shall release or unlock

Engineering Design Engineering design assessment consists of two events 1) Design Report 2) Design Evaluation

Design Report The design report should clearly explain the engineering and design process that was used in developing each system of the team’s Mini Baja vehicle. The process for each system could include: 1> Objectives 2> Customer requirements 3> Alternatives considered 4>The result(s) of design calculations 5>Stress Analysis 6>Testing Design reports must follow the format for SAE Technical Papers

Design Report - Format The design report file must be named as follows: Car #_college name EXAMPLE: Car # 14 VIT

Design Report – Page Limit The technical paper segment of design report is limited to ten (10) pages, excluding the cover page. Additionally the report may, at the team’s option, include up to four (4) nontext, pages of plans, graphics, photographs or other data for a maximum of fourteen (14) pages of information. The only text permitted on the four (4) optional pages are captions. All pages must be either 8 ½ “x 11” or A4. NOTE: If your paper exceeds 10 pages of technical report or 4 pages of graphics, then only the first 10 technical and 4 graphic pages will be evaluated.

Design Report – Deadline and Submission Design reports must be received not later than the due date of 15th Dec 2014. 2014. Any Design Report not received by the due date will be subject to a penalty of ten (10) points for each day after the deadline. Both soft & hard copies are required. Teams that do not submit a Design Report will not be judged in either part of the Design Event and will receive zero (0) points.

Design Evaluation Design Evaluation will be conducted at the event site on the first full day of the competition. Cars are expected to be presented for Design Evaluation in essentially finished condition, i.e. fully assembled, complete and readyready-toto-run. Vehicles presented in an unfinished condition may receive lower, or zero points for any incomplete areas that can not be fully assessed by the design judges. Additionally, the judges have the right to refuse to evaluate incomplete vehicles. Teams that are refused judging because of incompleteness will receive zero points for Design Evaluation.

Design Evaluation During design evaluation team members are expected to be able to fully explain and discuss all aspects of their vehicle’s design and the rationale behind their design decisions. Teams that are unable to adequately explain the various aspects of their design to the judges satisfaction will receive lower scores down to, and including, zero (0) points.

DFMEA Design Failure Mode & Effect Analysis

Potential Failure Mode and Effects Analysis (Design FMEA)

__ System __ Subsystem __ Component Model Year/Vehicle(s): Core Team:

Item

Function

Potential Failure Mode

FMEA Number: Page 1 or 1 Prepared by: FMEA Date (Orig.):

Design Responsibility Key Date:

Potential Effect(s) of Failure

Potential O C S L C Cause(s)/ E A Mechanism(s) C U V S Of Failure S R

Current Design Controls Prevention

Current Design Controls Detection

D Action Results Responsibility E R. Recommended & Target S O D R. T P. Completion Actions Action(s) E N. E C E P. Date Taken V C T N. C

48

FMEA Procedure List all Function & requirements

Re- evaluate (New RPN )

List all conceivable failure modes Consider effects, if above failure mode happens Look possible causes & mechanism for failures mode Assess the frequency of occurrence of failure modes (O)

Define Responsibility & Time- frame Recommend improvements Calculate the Risk Priority Number (RPN) Assess the possibility of Failure being detected ( D )

Assess the Severity of effect (s)

FMEA Sequence Subsystem

Potential failure mode

Potential S C Potential Effect(s) of E L Cause(s) Failure V A Mechanism(s) S of Failure S

O C C U R

Current Controls

Function Requires

What are the effect(s)?

How bad is it?

What are the Functions, Features or Requirements? What can go wrong? - No function - Partial/ over/ degraded function - Intermittent function - Unintended function

What are the cause(s)?

How often does it happen? How can this be prevented and detected?

D R Recommende Responsi E P d bility & T N Action(s) Target E completio C n date T I O N

What can be done? - Design changes - Process changes - Special controls - Changes to standards, procedures, or guides

How good is this method at detecting it?

Action results

Act- S O D R. ions E C E P. take V C T N. n

S.O.D. Tables & its usage

Occurrence table Occurrence (o) Suggested Evaluation Criteria: Probability of Failure Very High : Persistent failures

Possible Failure Rates > 100 per thousand vehicles/ items 50per thousand vehicles/ items

Ranking 10 9

High : Frequent failures

20 per thousand vehicles/ items

8

10 per thousand vehicles/ items

7

5 per thousand vehicles/ items

6

2 per thousand vehicles/ items

5

1 per thousand vehicles/ items

4

Low : Relatively few failures

0.5 per thousand vehicles/ items

3

0.1 per thousand vehicles/ items

2

Remote : Failure is unlikely

< 0.010 per thousand vehicles/ items

1

Moderate : Occasional failures

Severity table Effect Hazardous without warning

Criteria : severity of Effect Ranking Very high severity ranking when a potential failure mode affects safe 10 vehicle operation and/or involves noncompliance with government regulation without warning.

Hazardous with warning

Very high severity ranking when a potential failure mode affects safe vehicle operation and/or involves noncompliance with government regulation with warning.

9

Very High High

Vehicle/ item inoperable (loss of primary function). Vehicle/ item operable but at reduced level of performance. Customer very dissatisfied.

8 7

Moderate

Vehicle/ item operable, but Comfort/ Convenience item(s) inoperable. Customer dissatisfied.

6

Low

Vehicle/ item operable, but Comfort/ convenience item(s) operable at a reduced level of performance. Customer somewhat dissatisfied.

5

Very Low

Fit & Finish/ Squeak & Rattle item does not conform. Defect noticed by most customers (greater than 75%).

4

Minor

Fit & Finish/ Squeak & Rattle item does not conform. Defect noticed by 50% of customers.

3

Very Minor

Fit & Finish/ Squeak & rattle item does not conform. Defect noticed by discriminating customer (less than 25%).

2

None

No discernible effect.

1

Detection table Suggested Evaluation Criteria: For Detection Criteria : Likelihood of Detection by Design Control Ranking detection Absolute Design control will not and/or can not detect a potential cause/ 10 Uncertainty Very Remote Remote Very Low Low Moderate Moderate High High Very High Almost Certain

mechanism an subsequent failure mode; or there is no Design control Very remote chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Remote chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Very low chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Low chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Moderate chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Moderate high chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. High chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Very high chance the Design control will detect a potential cause/ mechanism and subsequent failure mode. Design control will almost certainly detect a potential cause/ mechanism an subsequent failure mode.

9 8 7 6 5 4 3 2 1

RPN / Risk Priority Number Top 20% of Failure Modes by RPN R P N

Failure Modes

DVP&R Design Validation Plan & Report

Why Design Validation?? Validation?? ‘Are we building it right?’ Major costs of projects are incurred in early design stages. The cost of fixing a design and faulty decisions at later stages is exponentially greater than at an earlier stage. Early involvement of CFT in product development saves time and money over product life.

Validation Definition The documented act of proving that any procedure, process, equipment, material, activity or system, actually leads to the expected results. Design Validation means establishing by objective evidence that device specifications conform to user needs and intended uses.

Requirements of Design Validation Design validation shall be performed under defined operating conditions on initial production units, lots or batches, or their equivalents. It includes testing of production units under actual or simulated use conditions. It includes software validation and risk analysis. The Validation must be documented in Design Validation Plan.

Design Validation Process Validation Plan Validation Review Validation Methods Validation Report

Comparison Between Validation, Verification & Review

Design Validation Plan (DVP) Design Validation is next step to DFMEA. Depending upon RPN in DFMEA the components are arranged in DVP. It contains all the information regarding the acceptance criteria, responsible person or team, type of test and start & finish dates.

Validation Methods Testing ( Static as well as Dynamic) Analysis ( Using software's and simulations) Inspection Methods(Visual or with Test Rigs) Compilation of relevant scientific literature Study of historical evidences of similar design

Examples of validation methods & activities Worst case analysis of an assembly. Fault tree analysis of a process or design. Failure modes and effects analysis (FMEA). Package integrity tests. Testing of materials. Comparison of a design to previous vehicles having an established history of successful use.

All the best for BAJA SAEINDIA 2014