ENGINEERING ETHICS: THREE CASE STUDIES
ENGINEERING ETHICS:THREE CASE STUDIES(Subtitle:EVERYTHING SHOULD BE AS SIMPLE ASPOSSIBLE, BUT NOT SIMPLER)Victor Singer, P.E. (retired)Dan Schiffbauer, P.E.Toshiba
OVERVIEW: Canons or Codes of Ethics Noteworthy Historical Background for Each Case In Point– The Tacoma Narrows First Suspension Bridge: failed 1940– The Silver Bridge (US Hwy 35 Ohio River Crossing): failed 1967– The Shuttle Challenger: failed 1986 Questions To Ponder For Each Case In Point:–––––Are There Relevant Ethical Issues Or Just 20-20 Hindsight?When, If At All, Did Which Ethical Issue Come Into Play?If Errors Occurred, Were They Errors Of Judgment, Omission or Commission?Or Murphy’s Law Events - - Accidents In An Imperfectly Understood World?Who Should Have Done What, That He Didn't Do?
CANONS OR CODES OF ETHICS NSPE, ASCE, ASME, AAES: Engineers shall hold paramount the safety,health and welfare of the public . . . (Fundamental Canon) AIChE: Members shall hold paramount the safety, health and welfare ofthe public . . . IEEE: We, the members of the IEEE . . . , do hereby . . . agree to acceptresponsibility in making decisions consistent with the safety, health andwelfare of the public . . . AIAA: The AIAA member will have proper regard for the safety, healthand welfare of the public in the performance of his professional duties. AIA: Members should . . . thoughtfully consider the social andenvironmental impact of their professional activities. ABA Model Code of Professional Responsibility: Canons:1.2.3.4.5.6.7.8.9.A lawyer should assist in maintaining the integrity and competence of the legal profession.A lawyer should assist the legal profession in its duty to make legal counsel available.A lawyer should assist in preventing the unauthorized practice of law.A lawyer should preserve the confidences and secrets of a client.A lawyer should exercise independent professional judgment on behalf of a client.A lawyer should represent a client competently.A lawyer should represent a client zealously within the bounds of the law.A lawyer should assist in improving the legal system.A lawyer should avoid even the appearance of professional impropriety.
CASE IN POINT: TACOMA NARROWSFIRST SUSPENSION BRIDGE Highway 16 Puget Sound Crossing between Tacoma WA and Kitsap Peninsulaopened to traffic 7/1/1940; collapsed 11/7/1940; 6-minute video of collapseat http://www.youtube.com/watch?v j-zczJXSxnwfrom: http://en.wikipedia.org/wiki/Tacoma Narrows Bridge (1940)
VON KARMAN VORTEX STREET(observed from space): Wind blowing above the sea is disturbed by an island, creating a "vortex street."Clouds serve as markers, allowing us to see the vortices in the flow downstreamof the island.Von Karman Vortex Street in the atmosphere: SeaWiFS image courtesy of Orbimage,Inc., SeaWiFS Project (Code 970.2) and Distributed Active Archive Center (Code 902) atNASA's Goddard Space Flight Center, Greenbelt, MD
TACOMA NARROWS BRIDGE: before,during and after failure 3 hrs transverse flexural (up and down) vibration, amplitude 1.5 ft, 35 mph windWind rose to 42 mph, a midspan hanger cable broke (slipped), and the torsionalmode started. Frequency 0.2 Hz, 28 ft double amplitudeFrequency associated with von Karman vortices at 42 mph wind: 1 HzFederal Works Agency's Failure Commission concluded: Vortex shedding unlikelyimportant because of the frequency difference.Violins teach that excitation with RANDOM frequency content producesresponses at resonant frequencies AND AT HARMONICS unless the vibratingsystem provides substantial internal damping.Currently popular attribution: AEROELASTIC FLUTTER: jargon for stimulation ofmultiple degrees of freedom CONCURRENTLY, A MURPHY’S LAW EVENT.
SIMILAR PHENOMENAfrom: www.clarktesting.comStockbridge Damper (SCE 1928)
PROTECTION AGAINST MURPHY’SLAW EVENTS In general, interpolate within rather than extrapolate beyondprior experience.Extrapolate in small steps, only where risk and benefits arebalanced.Tacoma Narrows Bridge was a substantial extrapolation intothe unknown.Much lower flexural rigidity and torsional rigidity than priorart, to reduce cost.Eminence of the designer - - Leon Moisseiff - - played role insuppressing criticism.Exception - - David B. Steinman, also an eminent suspensionbridge designer, criticized the design at a 1938 meeting of theASCE Structural Division.Othmar Ammann (Failure Commission member) wrote:– "The failure has given us invaluable information. . . [that] every newstructure that projects into new fields of magnitude involves newproblems . . . [for] which neither theory nor experience furnish anadequate guide. It is then that we must rely on judgment. If errors orfailures occur, we must accept them as a price for progress."
QUESTIONS TO PONDER– Are There Relevant Ethical Issues Or Just 20-20 Hindsight?– When, If At All, Did Which Ethical Issue Come Into Play?– If Errors Occurred, Were They Errors Of Judgment, Omission or Commission?– Or Murphy’s Law Events - - Accidents In An Imperfectly Understood World?– Who Should Have Done What, That He Didn't Do?
SECOND CASE IN POINT: THE SILVERBRIDGE US Highway 35 Ohio River Crossing, Point Pleasant WV to Kanauga Ohio.– completed 1928, collapsed 12/15/1967 center span 700 ft, side spans 380 ft each,deck width 28 ftfrom: http://en.wikipedia.org/wiki/Silver Bridge
SILVER BRIDGE 46 dead, 2 missing (never found)
HERCILIO LUZ BRIDGE Florianopolis, Brazil– (26 deg S latitude) center span 1113 ft. Opened 1926, closed 1982, re-opened(pedestrians) 1988, closed 1991 Designers: David B. Steinman and Holton D. Robinson– Using eyebar chain as upper chord of stiffening truss reduced weight and cost.– American Bridge Company proposed using their "special" 1060 carbon steel eyebarsheat-treated to over 2X strength of the 1020 ASTM A-7 in common use.– Steinman dissociated his firm from further connection with the project.
SILVER BRIDGE: concept &proportions copied from Florianopolis For main span 2/3 as long, chain tension force was about half as large, allowing chainswith only two heat-treated 1060 steel eyebars rather than four as on Florianopolis.If one outer eyebar breaks, pin cannot sustain unsymmetrical load; bridge comesdownEyebars 12” x 2”, Eye dia 28 in. Pin dia 11 inchesHeat Treat: ST 875 degC, WQ, temper 625 degC 2 hrs.Average eyebar properties: Ftu 120 ksi, Fty 81 ksi, El 20%, R/A 45%, CVN 2 to 3 ftlbs at 32 degF, KIc 46.4 ksi root inchOther steel shapes and plate (1020 carbon steel, ASTM A7-24) Ftu 58.2 ksi, Fty 31.7ksi, El 20.7%, R/A 50%, CVN 15 ft lb at 50 degF, KIc 100 ksi root inchEyebar allowable stress 50 ksi (67% of min required elastic limit)
Ignorance is Truly Bliss Only one recovered eyebar had a broken head Fracture Surface, lower side: corner crack 0.28 inch long (parallel to 2 inch thickness), and0.12 inch deep radially.Technology enabling quantifying the relationship between flaw size and failure load didn'tyet exist in the 1920's when Silver Bridge was designed.1920’s era brittle fracture provisions for steels for buildings and bridges commonlyreflected a 15 ft lb minimum CVN (Charpy Vee Notch Impact Test)Eyebar steel, at 2X the strength, provided less than 20% as much fracture energySteinman’s view (evidently): Stronger eyebars either too much extrapolation from priorexperience or too little fracture energy for Florianopolis, as far from equator as Miami andmuch warmer than Kanauga.
SILVER BRIDGE: post-mortem Found original stress analysis reasonably accurateEvaluated actual loading at time of failure to estimate actual load on failedeyebar.Conducted extensive material testing program, including modern fracturetoughness tests and related crack growth rate quantifications, and scale modeltesting program.Final Highway Accident Report NTSB Report SS-H-2 (adopted 12-16-1970):Fig 36: approximate positions of all vehicles on the bridge at time of failure.Westbound lane 1/3 empty, eastbound lane more than half empty.Page 98: "the probability of 100 percent of design stress is quite remote."Failed eyebar head obviously loaded to actual capability when it failed.The state-of-the-art circa 1920’s lacked recognition of potential premature - - flawinduced - - failure in brittle materials at low temperatures.– Fracture cause: a flaw grew over 40 years to critical size by stress corrosion andcorrosion fatigue. Which was dominant is unknown.– No indication main member deterioration by rusting to a point of inadequacy underintended or actual loading.–––––
QUESTIONS TO PONDER– Are There Relevant Ethical Issues Or Just 20-20 Hindsight?– When, If At All, Did Which Ethical Issue Come Into Play?– If Errors Occurred, Were They Errors Of Judgment, Omission or Commission?– Or Murphy’s Law Events - - Accidents In An Imperfectly Understood World?– Who Should Have Done What, That He Didn't Do?
THIRD CASE IN POINT: SHUTTLECHALLENGERWhat SHOULD happen: SPACE SHUTTLE DISCOVERYat STS-120 LaunchWhat DID happen: SPACE SHUTTLE CHALLENGERat SPS-25 Launch Jan 28, 1986
BACKGROUND: Space ShuttleProgram OverviewAPOLLO flight vehicle Vehicle Architecture: Shuttle's"Stages In Parallel" architecturewas a substantial departure fromApollo and Mercury "Stages InSeries" architecture. Re-Usable Orbiter objective madeCrew Capsule Jettison feature ofApollo and Mercury programsmore difficult than before. NASA Decision: NO CREWCAPSULE ESCAPE SYSTEM FORSHUTTLE
BACKGROUND Space ShuttleProgram Overview cont’d. Funding Strategy: Seek Congressional approval by earmarking at least onecomponent supplier contract for each US Senatorial and Rep District in thecountry.Delaware got space suits, Wisconsin got SRM steel cases, Minnesota got phenolicresin impregnated carbon cloth, Virginia got rayon for white woven cloth (carboncloth precursor), Nevada got ammonium perchlorate oxidizer for solid propellant,etc.Congressional direction to NASA: YOU TELL US that revenue from commercialflights will cover the program development costs.– Interpretation: "You tell us" more important than whether or not it's true.– Responses: 1) Flight schedule large enough to recover program development costs;2) Intense program-long focus on costs. Original launch schedule built from "modest" start to SIXTY flights/year; peaklaunch rates actually achieved: 9 in 1985 and 8 in 1997.All ground support systems designed AND BUILT to support 60 flights/yearschedule.
SUBTLE DEMONSTRATION OF NASA“SHOP CULTURE” Projected 60 flights per year schedule is one flight every six days.Time in orbital flight much longer than time during ascent.Potential for damage by collision with space junk (natural or otherwise) duringascent or orbital flight, precluding normal return, should be among designconsiderations.Obvious solution: Standing policy NOT to fly Flight "X" until Flight "X 1" iswithin six days of flight-ready.No such policy was in effect when the Shuttle Columbia failed re-entry (2/2003).After Columbia, it was implemented for only one of the several additional flights.Credible reason: In the year such a policy becomes effective, implementationrequires paying for one more total vehicle build-up than the number of flights.Cost impact first year, no impact thereafter.MANAGEMENT DECISION: Do it NEXT year. Cost out-ranks safety.
CLEVIS JOINT CROSS SECTION(schematic)A - steel wall thickness 12.7 mm, B - Primary O-ring, C - Backup O-ring,D - Cork cover band, E - insulation, F - insulation, G - carpeting,H - sealing paste, I - propellant
IMPLICATIONS OF SPACE SHUTTLESRM SERVICE TEMPERATURE NASA specification: demonstrate capability to operate between 40 degF and 90 degF.–––– SRM Thermal mass judged sufficient to bridge excursions higher or lower.Lowest temp full scale demo, at 53 degF, showed primary O-ring blow-by.Effect of adjacent orange tank for cryogenic fuel and oxidizer unrecognized.Orange tank caused convection; SRM case temp was often below 40 degFSRM clevis joint was originally proportioned to INCREASE O-ring squeeze withrising pressure.After case fab was well under way, NASA initiated weight reduction to increasepayload by reducing SRM case cylinder thickness between clevis joints. Thischanged clevis joint behavior, DECREASING O-ring squeeze with rising pressure.O-ring (artificial rubber) stiffens with decreasing temp,Squeeze loss during pressurization prompted intense experimental inquiry intoO-ring material behavior: Would prior squeeze relax fast enough to maintain sealduring ignition pressurization and thereafter.Result: Yes (on paper) at 40 degF and higher, but 53 degF was lowest actualfully credible verification from an early 1985 flight.
PRE-LAUNCH ACTIVITY AT THE CAPE Evening before launch, at Readiness Review Meeting, anticipated weather for1/28/1986: 29 degF at 9 am, 38 degF at 2 pm (without convection effect)MTI lead on-site rep presented charts leading to first (engineering)recommendation: "O-Ring temp must be 53 degF (or greater) at launch."NASA on-site reps asked for and got MTI higher management telecomconcurrence. After off-line conference, top management in Utah withdrew earlierobjection.Launch day morning observations: ICE EVERYWHERE ! !– Local ambient air temp 26 degF– ICICLES HANGING FROM AFT SEGMENT STIFFENING RINGS ! !– Hand-Held Infrared Pyrometer measurements on one of steel cases: near aft field joint: 9 degF, on aft skirt 7 degF– Ice Team informed Mission Management Team soon after 9 am.– No MMT discussion because measurements were for Engineering Information only, notpart of formal Launch Commit Criteria– Ice Team 10:30 am inspection disclosed ice still on one of the SRB's– Houston Mission Control reported that trajectory analysis of ice falling from orangetank during flight would not impact orbiter Launch was at 11:38 am
Failure on the Pad
THE GREEN BALL THEORY(title of Chapter 26 in "Truth, Lies and O-Rings: Inside the Space ShuttleChallenger Disaster" Allan J. McDonald with James R Hanson) Conversation, Al McDonald and Richard Feynman,physicist, Nobel Prize winner, Rogers Commissionmember, at impromptu May 1986 lunch: Summary of 13pages of text:– Feynman: Why did Morton Thiokol (MTI) management change their minds after theirinitial recommendation not to launch?– McDonald: Because of the Green Ball Theory.– Feynman: What's the Green Ball Theory?– McDonald: Management considerations: No signed contract for the next SRM buy;and NASA announced intent to seek a second source for SRM’s.– Feynman: So what does that have to do with a Green Ball Theory?– McDonald: What do you have when you have a green ball in your left hand andanother green ball in your right hand?– Feynman: I don't know. What DO you have?– McDonald: Complete and absolute control of the Jolly Green Giant!
QUESTIONS TO PONDER– Are There Relevant Ethical Issues Or Just 20-20 Hindsight?– When, If At All, Did Which Ethical Issue Come Into Play?– If Errors Occurred, Were They Errors Of Judgment, Omission or Commission?– Or Murphy’s Law Events - - Accidents In An Imperfectly Understood World?– Who Should Have Done What, That He Didn't Do?
TWO MESSAGES TO RECOGNIZE: We understand much;We don’t yet understand more.AND REMEMBER WHAT THE SECOND ONE TEACHES: Be cognizant of the need for further learning;Be attentive to what you see along your path.LEARNING IS LIKE DRIVING AT NIGHT: Our headlights illuminate only 300 feet of the road ahead; With continuing attention to details, we can travel far, reasonably safely.
POST-SCRIPT: COINCIDENCES INTERRELATE THE CASES IN POINT The Tacoma Narrows Bridge failure has been attributed to aeroelastic flutter.– Theodore von Karman, an aerodynamicist, long before the 1940 event, had quantifiedthe fluid flow condition later known as a von Karman vortex street, including itsperiodicity. He served in the failure investigation.– David B. Steinman, a structural engineer, strongly criticized the design before it wasbuilt, perhaps because it substantially extrapolated beyond prior experience. The Silver Bridge failed because its eyebar steel was twice as strong but ten timesas brittle as steels conventionally used in bridge and building construction.– Its design was copied from a similar David B. Steinman bridge in a warmer climate.– Steinman dissociated himself from that design when his client chose to use highstrength steel in its eyebars, to reduce cost. The Shuttle SRB's were built by a successor to Thiokol Chemical Corporation,which went into the rocket motor business when GALCIT's JPL started usingThiokol's polysulfide polymer to control the burn rate of black powder.JPL at the time was headed by Theodore von Karman, who coined the JetPropulsion Lab name.
CANONS OR CODES OF ETHICS NSPE, ASCE, ASME, AAES: Engineers shall hold paramount the safety, health and welfare of the public . . . (Fundamental Canon) AIChE: Members shall hold paramount the safety, health and welfare of the public . . . IEEE: We, the members of the IEEE . . . , do hereby .
series b, 580c. case farm tractor manuals - tractor repair, service and case 530 ck backhoe & loader only case 530 ck, case 530 forklift attachment only, const king case 531 ag case 535 ag case 540 case 540 ag case 540, 540c ag case 540c ag case 541 case 541 ag case 541c ag case 545 ag case 570 case 570 ag case 570 agas, case
Sampling for the Ethics in Social Research study The Ethics in Social Research fieldwork 1.3 Structure of the report 2. TALKING ABOUT ETHICS 14 2.1 The approach taken in the study 2.2 Participants' early thoughts about ethics 2.2.1 Initial definitions of ethics 2.2.2 Ethics as applied to research 2.3 Mapping ethics through experiences of .
Engineering Ethics: Case Studies College of Engineering GE106:Introduction to Engineering Design By Matthew Amao. Outline Wednesday, December 04, 2019 Introduction to Engineering Design GE-106 2 Case Study 1: Murder Case Study 2: Driving Over the Speed Limit
"usiness ethics" versus "ethics": a false dichotomy "usiness decisions versus ethics" Business ethics frequently frames things out, including ethics Framing everything in terms of the "bottom line" Safety, quality, honesty are outside consideration. There is no time for ethics.
Code of Ethics The Code of Ethics defines the standards and the procedures by which the Ethics Committee operates.! More broadly, the Code of Ethics is designed to give AAPM Members an ethical compass to guide the conduct of their professional affairs.! TG-109! Code of Ethics The Code of Ethics in its current form was approved in
Professional Ethics Professional societies develop polices for their own industries, and the societies hold their members to that code of ethics. Professional ethics is different from studying philosophical ethics. Professional ethics encompass how people work in a professional setting by following expected standards of behavior (Strahlendorf).
Ethics in Engineering . Presenter: Iqtidar Khan. President ISA Houston Section. Date: Oct 26, 2019. Agenda. 1. Speaker introduction 2. Understanding Ethics in Engineering . - Electrical & Automation Engineering Manager, Team sizes managed: - 20 to 150 Engineers and Designers. Understanding Ethics in Engineering
4. Ethics in engineering: 4.1 Purpose and concepts of engineering ethics, 4.2 Engineering as social experimentation, 4.3 Types of enquiry, 4.4 Issues in engineering ethics,. 5. Engineer's responsibility and Safety: 5.1 Safety, Risk, Underestimating the Risk, Over-estimating the Risk, Risk-Benefit analysis, 5.2 Cause of an accident and
