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Chapter 14: Bioengineering
Problems 1 and 2 concern the following situation: A car is traveling 30. mph hits a wall.
The car has a crumple zone of zero and the passenger is not wearing a seat belt. The
passenger’s head hits the windshield, and is stopped in the distance of 0.10 m. The skull
mass is 5.0 kg. The area of contact of the head and the windshield is 0.010 m2. Assume
direct contact (that is, ignore whiplash) and ignore the time it takes the passenger to reach
the windshield.
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14-1) Provide a graph of v - t graph of the collision of the skull and the windshield, and
then graph the force experienced by the skull as a function of time.
Need: v - t graph of the collision and F = _____ N (as fn. of time)
Know: v = 30. mph = 13. m/s; Ds = 0.10 m and A(contact) = 0.010 m2.
Skull mass = 5.0 kg.
How: v - t graph area relates to Ds and hence the time of impact. This gives
the deceleration and thus the acting force.
Solve: Ds = ½ v0 × ts; hence ts = 2 × 0.10/13.0 [m][s/m] = 0.015 s.
(Constant) deceleration rate = v0/ts = 13.5/0.015 [m/s][1/s] = 850 m/s2.
Force on head at contact is m × a = 5.0 × 850 [kg][m/s2] = 4,200 N and
lasting 0.015 s.
13.4
m/s
13. m/s
Ds= ½ v0 × ts
= 0.10 m
Force, N
4,500
4,200
v
0
ts
t
0
t, s
ts = .015 s
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14-2) If the compressive strength of bone is 3.0 × 106 N/m2, will the collision in the
previous exercise break the skull?
Need: Max allowable stress on skull exceeded = _____ (yes/no)
Know: Contact area = 0.010 m2 and force is 4,200 N. Compressive strength
of bone = 3.0 × 106 N/m2.
How: Compute force per unit area (which is the same as the energy per unit
volume) of collision, and compare to compressive strength of bone
Solve: Force = 4,200 N. ∴Force/area = stress = 4,200 /0.01 [N][1/m2] =
4.2 × 105 N/m2 (<< than the compressive strength of bone, so no, the skull
will not be broken, but other very serious injuries may still occur within the
head or neck)
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Problems 3 and 4 concern an experiment in the 1950s when Air Force Colonel John Paul
Stapp volunteered to ride a rocket sled to test the resistance of the human body to “g
forces”. The sled accelerated from 0 to 625 miles per hour in 5.0 seconds. Then the sled
hit a water brake and decelerated in 3.0 seconds to a standstill. Assume that Stapp was
rigidly strapped into the sled, and he had a mass of 75 kg.
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14-3) Prepare v – vs.- t and F – vs.- t graphs of Stapp’s trip, and compute the “g forces” he
experienced in the course of acceleration and deceleration.
Need: v – vs.- t and F – vs.- t graphs and g = ____ [0].
Know: vmax = 625 mph = 279 m/s. Constant acceleration for 5.0 s and
constant deceleration for 3.0 s.
How: Acceleration is slope of line.
Solve: Acceleration phase: a = (279 – 0/(5.0 – 0.0) [m/s][1/s] = 55.8 m/s2
or g = 55.8/9.8 [m/s2][s2/m] = 5.7 [0] or = 5.7 g.
During deceleration phase, a = (0 – 279/(3.0 – 0.0) = - 93 m/s2 = - 93/ 9.8
[m/s2][s2/m] = -9.5 [0] or = - 9.5 g.
279 m/s
5.7
F, g
v
t
0, 0
t
0,0
5.0 s
3.0 s
-9.5
5.0 s
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3.0 s
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14-4) Using the force vs. time graph (Figure 14.6) for human resistance to “g forces”,
predict whether Stapp suffered serious injury in the course of his record-breaking trip in
the worse case.
Need: Was Stapp’s maximum g force that was experienced for a duration
of 3.0 second in the “serious injury or death” region = ______ yes/no?)
Know - How: Graph of g force vs. duration is provided as Figure 14.6.
Solve: Stapp’s experience of 9.5 g for 3.0 seconds is right at the “serious
injury or death line”. GSI = a2.5ts = 835!
(Col Stapp did indeed survive. His experiments established important data
points along the graph used in this example. Before his experiments, it was
believed that humans would not withstand more than 20 g at all without
serious injury. )
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14-5) A tall person sits down onto a sofa to watch TV. Assume that the center of gravity
of the person falls 1.0 m with constant gravitational acceleration in the course of sitting
down. The sofa compresses by 0 .05 m. Assume constant deceleration. Determine the g
forces experienced by the person in the course of this sitting down.
Need: g forces on a tall couch potato = ____ g
Know: During the time to hit the sofa, the person is in free fall; there are no
imposed forces until the person is slowed by the couch.
How: Use v - t diagrams a) to find speed at which person hits the couch and
b) the subsequent deceleration.
v, m/s
m/ 2
s
v0
Ds = 0.05 m
9.8
1
Solve:
1.0 m
0, 0
t1
0, 0
t2
a) To solve for v0 we use two facts from the first of these figures:
Acceleration = 9.8 m/s2 = v0/t1 and distance traveled = 1.0 m = ½ v0 × t1 so
that by eliminating t1, v0 = √(2 × 9.8 × 1.0) √[m/s2][m] = 4.4 m/s.
b) In diagram 2, Ds = 0.05 m = ½ v0 × t2 = ½ × 4.4 × t2. Hence t2 =
0.10/4.4 [m][s/m] = 0.023 s.
Hence max. deceleration = 4.4/0.023 [m/s][1/s] = 191 m/s2 = 191/9.8
[m/s2][s2/m] = -20. [0] = 20. g (so be kinder to couch potatoes!).
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Problems 6 and 7 concern an infant’s rear-facing safety seat as illustrated below.
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14-6) A rear facing child safety seat holds a child of mass 12. kg rigidly within the interior
of a car. The area of contact between the seat and the child is 0.10 m2. The car undergoes a
30. mph collision. The car’s crumple zone causes the distance traveled by the rigid interior
to be 1.0 m. Give the stress experienced by the child’s body in terms of a fraction of the
breaking strength of bone assuming an infant’s bone breaks at a stress of 10. MN/m2.
Need: Stress experienced by child’s body = ____ × breaking stress of bone.
Know: Impact at 30. mph = 13. m/s; deceleration distance = 1.0 m and
contact area = 0.10 m2. Breaking stress in infant’s bone = 10. MN/m2.
How: Find duration of accident tf from v – t diagram. Find deceleration
from v0 and tf.
Find force from F = ma and find stress from force/area. Compare to
breaking stress of 10. MN/m2.
Solve: From v – t diagram, 1.0 m = ½ ×13.0 ×
tf [m/s][s] so that tf = 2.0/13. = 0.15 s.
13.4m/s
m/s
13.
1.0 m
v
Hence deceleration rate for infant = 13. /0.15
= 87. m/s2. ∴ Force on baby = 12. × 87. [kg][
m/s2] = 1.0 × 103 N.
0,0
tf
∴Stress = 1.0 × 103/0.10 = 1.0 × 104 N/m2.
As fraction of breaking stress, 1.0 × 104/ 10. × 10-6 = 1.0 × 10-3. Bones
should hold and infant should be safe.
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14-7) A rear facing child safety seat holds a child of mass 25. kg rigidly within the rigid
interior of a car. The area of contact between the seat and the child is 0.10 m2. The car
undergoes a 30. mph collision. The car has no crumple zone, but a harness attached to the
car seat stops it uniformly within a distance of 0.30 m. According to the Gadd severity
index, will the child sustain serious injury or death?
Need: Child ___ (will/will not) suffer serious injury or death.
Know: Child’s mass = 25. kg. Initial speed at impact is 30. mph (13. m/s)
and deceleration distance = 0.30 m. In addition, contact area for child is
0.10 m2.
How: GSI = a2.5tS (with tS in seconds and a
in g) < 500 means no injury. Need to
calculate a and tS from stopping data. Use
v – t diagram.
13.4 m/s
Solve: Ds = 0.30 m = ½ × 13. × ts [m/s][s]
so that tS = 0.60/13. = 0.046 s.
v
Deceleration rate = 13. /0.046 [m/s][1/s] =
280 m/s2 = 280/9.8 [m/s2][s2/m] = 29. [0] =
2.9 g.
Hence GSI = a2.5tS = 2.92.5 × 0.044 = 210 <
500 and thus serious injury/death is unlikely.
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0.30 m
0,0
ts t s
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14-8) Consider a parachute as a safety device. When parachute opens the previously freely
falling person has typically reached a speed of about 50. m/s. The parachute slows to a
terminal speed of about 10. m/s in 1.3 s. Approximating this set of motions by a constant
deceleration, what is the maximum g experienced by the parachutist?
Need: maximum acceleration = ___ g
Know: Deceleration occurs between v =
50. m/s and 10. m/s in 1.3 s.
50. m/s
Deceleration
v
How: Use v – t diagram.
Solve: Deceleration = change in speed/time
= (10. – 50.)/(1.3 – 0.0) [m/s][1/s] = - 31.
m/s2;
10. m/s
∴g = - 31./9.8 = -3.1
1.3 s
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14-9) In the previous problem, the force exerted by the parachute is spread by a harness in
contact with 0.50 m2 of the parachutist, and the parachutist has a mass of 75. kg, what is
the force per unit area (stress) experienced by the person during the deceleration?
Need: Stress = ____ N/m2
Know - How: Deceleration of parachutist = -31. m/s2 and mass is 75. kg.
Harness area = 0.50 m2. Force is m × a and the stress = force/area
Solve: Force = 75. × 31. [kg][m/s2] = 2300 N
∴Stress = 2,300/0.50 = 4,600 N/m2
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14-10) The parachutist in the previous two exercises
hits the ground (still wearing the parachute!) and is
stopped in a distance of 0.10 m. If this final
deceleration is constant, calculate the Gadd Severity
Impact of the landing.
Need: GSI = ____ (a number)
455
10. m/s
0.10 m
v
Know: Terminal speed = 10. m/s. Mass =
75. kg and stopping distance is 0.10 m.
How: Use v – t diagram & GSI = a2.5tS.
0,0
ts
ts
Solve: Time of stopping = 2 × 0.10/10. [m][s/m] = 0.020 s.
Hence deceleration rate = 10./0.020 [m/s][1/s] = 500 m/s2 or g = 500/9.8 =
51 g.
∴ GSI = a2.5tS = 512.5 × 0.02 = 370 < 500 (and parachutist should be OK)
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14-11) A 75. kg person jumping from a 1.00 × 103 m cliff will reach a terminal speed of
50. m/s and uses a 1.00 × 102 m bungee cord to slow the descent. The bungee cord exerts a
force F proportional to its extension, where F (in newtons) = (5.0 N/m) × (extension in m)
and is designed to extend by 5.00 × 101 m in the course of bringing the user to a stop just
above the ground. Is the maximum deceleration in g experienced by the falling person
more or less than the maximum deceleration experienced by a parachutist undertaking the
same leap (excluding landing forces)?
Need: Maximum deceleration for bungee is ____ (greater/equal/less) than
for parachute.
Know: Initial height = 1.00 × 103 m; max stretch = 5.00 × 101 m and
restraining force on jumper = 5.0 × (extension in meters.) Jumper’s
terminal speed is 50. m/s.
How: Compute maximum deceleration = ____ in g.
Maximum deceleration occurs where the restraining force is maximum at 5.00 ×
101 m or F = 5.0 × 5.00 × 101 [N/m][m] = 2.5 × 102 N.
The corresponding bungee’s jumper’s deceleration is 2.5 × 102/75. [N][1/kg] = 3.3
[kg m/s2][1/kg] = 3.3 m/s2 or, in g = 3.3/9.8 = 0.34.
Excluding the landing, a parachutist’s maximum g forces occur when slowing
from 50. to 10. m/s (Exercise 10). The parachutist’s maximum g = 3.1 (excluding
landing) and was an order of magnitude > than that experienced by bungee
enthusiast.
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14-12) The airbag is designed to inflate very quickly and to subsequently yield if the
driver hits it. A collision uniformly stops a car from 30. mph to 0.0 and then triggers the
air bag. The driver is not seat belted and so hits the inflated airbag. This acts as a local
“crumple zone” and consequently compresses by 0.20 meters as his head is brought to
rest.
According to the Gadd Severity Index, will the driver suffer serious injury? Assume
constant deceleration of the driver’s head after hitting
the air bag.
13.4
13.m/s
m/s
Need: Driver ____ (will/will not) suffer
serious injury.
Know: Air bag will compress 0.20 m. Car
stopped from 30. mph (13. m/s). Head must
hit the air bag at v = 13.
m/s and stop after 0.20 m.
How: Deceleration rate from v – t diagram &
GSI (in appropriate units of g and seconds) =
a2.5tS < 500.
0.20 m
v
0,0
Solve: Head hits the air bag at 13. m/s and stops after 0.20 m. Stopping
time, 2 × 0.20/13. [m][s/m] = 0.031 s.
Deceleration rate = 13. /0.031 [m/s][1/s] = 420 m/s2 or 420/9.8 = 43. g.
∴GSI = 43.2.5 × 0.031 = 380 < 500 so that this driver should survive
without serious injury.
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t, s
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14-13) Two 100. kg football players wearing regulation helmets collide helmet to helmet
while each is moving directly at each other at 10.0 m/s and come to a near instantaneous
(<1 millisecond) stop. The area of contact is 0.010 m2, and the helmets are each designed
to provide a compression zone of 0.025 m. What is the maximum stress exerted on each
player?
Need: Stress = _____ N/m2
Know: Speed of each player is 10. m/s; their
masses are each 100. kg and their helmets
compress each by 0.025 m. Their collision time is
< 1 ms and their mutual contact area, helmet-tohelmet, is 0.010 m2.
20. m/s
v
How: If the players are moving at 10. m/s towards
each other, their relative speed is 20. m/s. Their
combined “crumple” zone is 0.050 m, from which
we can calculate their deceleration time and rate.
Use the v – t diagram.
0.050 m
0,0
Solve: From the v – t diagram, ts = 2 × 0.050/20.
[m][s/m] = 0.0050 s.
ts
t, s
∴ deceleration rate = 20./0.0050 [m/s][1/s] = 4,000 m/s2.
Each player will experience the same force: 100. × 4,000 [kg][m/s2] = 4.0 ×
105 N
∴stress on each player = force/area = 4.0 × 105/0.010 = 4.0 × 107 N/m2.
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14-14) A designer of football helmets has two options for increasing the safety of helmets,
but for economic reasons can implement only one. One option is to double the area of
contact that will be experienced in a helmet to helmet collision. The other is to double the
crumple distance experienced in a helmet-to-helmet collision. Which will be more
effective in reducing the maximum stress? (Hint: Try previous exercise first.)
Need: Which is more effective? ____ (doubling area of contact/doubling
crumple zone)
Know: Previous exercise is a representative calculation.
How: Repeat the previous exercise with variables in place of numbers and
get a formula for stress.
Solve: Assume total crumple zone (double that for one helmet) is Ds
meters. Assume time to dead stop is ts seconds.
Assume each player has mass m kg and
2v0 m/s
collides dead on at v0 m/s. Their relative
speed is thus 2v0 m/s. Let area of contact be
Ac.
From the v – t diagram, ts = 2 × Ds/2v0
[m][s/m] = Ds/v0 seconds
v
Ds m
Deceleration rate = 2v0/ts [m/s][1/s] = 2v02/Ds
m/s2.
Collision force = m × 2v02/Ds [kg][m/s2] =
2mv02/Ds N.
0,0
ts
∴ Stress at impact = Force/Ac = 2mv02/( Ac × Ds) N/m2.
Variables open to helmet designer are Ac & Ds. Doubling either will be
equally effective since both are included only to the first power.
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460
14-15) A soccer player “heads” a wet 0.50 kg soccer ball moving directly toward him by
striking it with his forehead. Assume the player initially moves his head forward to meet
the ball at 5.0 m/s and the head stops after the ball compresses by 0.050 m during impact.
Assume the deceleration of the head is constant during impact. Compute and comment on
the calculated Gadd Severity Impact of heading a soccer ball under these conditions.
5.0 m/s
Need: GSI = ____ (a number)
Know: Mass of ball is 0.50 kg; head initially at 5.0.
m/s. Time of collision set by 0.050 m compression
of ball coinciding will motion of head.
0.0500.05
m m
v
How: Use v - t curve.
Solve: From v - t curve, ts = 2 × 0.050/5. [m][s/m] =
0.020 s.
0,0
ts
2
2
2
t, s
2
Acceleration of head: 5.0/0.020 [m/s][1/s] = 2.5 × 10 m/s [m/s ][s /m]
and in g’s = 25.5 [0] = 26 g (appreciable!)
∴ GSI = a2.5 × ts = 262.5 × 0.020 = 69
This is below the 500 criterion for severe injury or death, but consider that experts 3 warn
against the dangers of small children repeatedly heading soccer balls!
3. See for example: http://www.physsportsmed.com/issues/1998/11nov/asken.htm
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14-16) A car strikes a wall traveling 30. mph. The driver’s cervical spine (basically the
neck) first stretches forward relative to the rest of the body by 0.010 m, and then recoils
backward by 0.020 m, as shown below. Assume the spine can be modeled by a material of
a modulus E = 10. GPa and a yield strength of 1.00 × 102 MPa. Will the maximum stress
on the cervical spine during this “whiplash” portion of the accident exceed the strength of
the spine? Assume a 0.15 m length of the cervical spine.
Need: Stress on cervical spine = _____ (greater than/equal to/less than)
tensile strength of spine?
Know: v0 = 30. mph = 13. m/s; cervical spine length = 0.15 m. During
stopping period, T2, spine stretches forward 0.01 m and on stopping at T3
backwards by 0.02 m. Elastic constants are E = 10. GPa and “transverse”
strength of 1.00 × 102 MPa for this failure mode.
How: Compute stress on spine from its strain. Compare to its strength.
Solve: Maximum stretch of cervical spine = 0.020 m.
∴Maximum strain of spine = 0.020/0.15 [m][1/m] = 0.13
∴Stress on cervical spine = modulus × strain = 1010 × 0.13 = 1.3 × 109
N/m2
Compare maximum stress on spine to tensile strength of spine
1.3 × 109 N/m2 (max stress) > 108 N/m2 (strength)
∴stress on cervical spine is greater than its tensile strength.
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14-17) Which do you think has been more effective in reducing fatalities on American
highways, seatbelts or airbags? Give an engineering reason for your answer, containing
variables, numbers and units. (Hint: Recall the SSSA formula previously developed and
consider what other safety element is designed into a modern automobile.) Then go on the
web and see if you were right.
Need: The more effective way of reducing fatalities is _____ (seatbelts or
airbags)
Know: Stress-speed-stopping-distance-area (SSSA) criterion relates the
stress developed in an accident.
How: Stress on a passenger in a car, σ = mv2/2ADS in which A and Ds can
both be varied by design.
Solve: Typical contact stress values for a 30 mph (~15 m/s) collision
without airbag or seatbelt for a 75 kg passenger are (assuming a hard
dashboard yielding only 0.01 m, with an area of contact only 0.01 m2) is ~
75 × 152/(2 × 0.01 × 0.01) [kg][m/s]2 [1/m2][1/m] ~ 108 N/m2, a potentially
fatal collision.
The airbag increases the distance of the deceleration to about 0.05 m, and
increases the contact area to about 0.03 m2, thereby making a reduction to ~
6 × 106 or a factor of 15 in the stress.
The seatbelt in older cars might still allow the head to meet the dashboard
or steering column since the body flexes according to the applied g forces.
But newer cars now have a rigidly framed passenger compartment that
stays intact during a 30 mph crash, and they have a crumple zone that
reduces the applied g forces. That means a person belted to a seat strongly
attached to the rigid frame will not hit the dashboard at all, distributing
deceleration over an area at least as great as the air bag (0.03 m2 or more).
In addition, the crumple zone increases Ds to perhaps thre quarters of a
meter. The stress criterion then yields 75 × 152/(2 × 0.03 × 0.75) ~ 4 × 105
N/m2. So the seatbelt leverages automobile improvements to give a stress
reduction of ~ 250 times over the unprotected passenger.
According to web resources, seatbelt use is estimated to save on the order
of 5000 - 10,000 lives per year, vs 500- 1000 per year for airbags. Note
however the emphasis on the word “use”. It is still the case that a sizeable
fraction of drivers, perhaps as much as one-third, do not fasten their
seatbelts. On a $ invested in safety equipment per life saved, the
advantages of seatbelts are even more striking.
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463
18) As a bioengineer at the Crash Safety Test Facility of a major automobile company,
you are asked to provide more data for the Gadd Severity Index (Figure 14.6 of this
chapter). Your boss suggests using live animals, dogs and cats from the local pound, in
hard impact tests and then inspecting them for injury. You know their injuries will be
severe or fatal, and using dogs or cats seems cruel. What do you do?
a) Nothing, live animals are used regularly in product testing, and besides they will
probably be killed in the pound anyway.
b) Suggest using dead animals from the pound, since their impact injuries probably
don’t depend on whether or not they are alive.
c) Suggest using human cadavers since you really want data on humans anyway.
d) Suggest developing an instrumented human manikin for these tests.
Use the Engineering Ethics Matrix format to summarize your conclusions.
1) Apply the Fundamental Canons: Engineers, in the fulfillment of their professional
duties, shall:
1) Hold paramount the safety, health, and welfare of the public - this canon
requires you to first find out if there are data from live animal studies
that are essential to drawing conclusions about human safety, but can’t
be obtained in other ways. If so, then this canon argues in favor of
option a).
2) Perform services only in the area of their competence - applies equally
to all options.
3) Issue public statements only in an objective and truthful manner applies equally to all options.
4) Act for each employer or client as faithful agents or trustees - the
answer here depends on whether your boss has relevant expertise
beyond yours in the field. If you judge that the boss does, this must
incline you toward accepting the boss’s recommendation and accepting
option a)
5) Avoid deceptive acts - Applies equally to all options
6) Conduct themselves honorably, responsibly, ethically, and lawfully so
as to enhance the honor, reputation and usefulness of the profession—This
canon argues in favor of options b), c), and d), even if live animal data
would provide irreplaceable information for human safety. Sacrificing
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animals to improve products certainly will not enhance the honor,
reputation and usefulness of a profession.
2) Engineering Ethics Matrix
a) Nothing
b) Suggest
use of dead
animals
from pound
c) Suggest
use of
human
cadavers
Meets canon
Meets
canon
Meets canon
d) Suggest
development
of
instrumented
mannequin
Meets canon
Meets canon
Meets
canon
Meets canon
Meets canon
Silence here
is an
untruthful
public
statement
Meets
canon
Meets canon
Meets canon
Meets
Risks harm
to employer’s canon
reputation
Meets canon
Meets canon
Does not
apply
Meets
canon
Meets canon
Meets canon
Not
honorable in
disregard for
issues of
animal
welfare
Meets
canon
Meets canon
Meets canon
Options
Canons
Hold
paramount
the safety,
health and
welfare of
the public.
Perform
services only
in the area of
your
competence
Issue public
statements
only in an
objective and
truthful
manner
Act for each
employer or
client as
faithful
agents or
trustees
Avoid
deceptive
acts
Conduct
themselves
honorably …
Solution: The ethical problem comes down to balancing canon 1 and canon
6. Is the potential payoff in terms of human health and safety sufficient to
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justify the harm to a profession, and to one’s personal ethics, that live
animal tests would cause? Only if the data from live animal tests are
essential and irreplaceable in saving lives is there an ethical argument for
live animal tests.
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14-19) You are now a supervisor in the bioengineering department of a major motorcycle
helmet manufacturer. Your engineers are testing motorcycle helmets manufactured by a
variety of your competitors. Motorcycle helmets contain an inner liner that crushes upon
impact to decrease the deceleration of the head on impact. This liner material is very
expensive, and can only be used once (i.e., once the helmet sustains a single impact it
must be replaced.) Your company has developed an inexpensive liner that will withstand
multiple impacts, but is less effective on the initial impact than any of your competitors.
The Vice President for Sales is anxious to get this new helmet on the market and is
threatening to fire you if you do not release it to the manufacturing division. What do you
do?
a) Since your company has invested a lot of money in the development of this
helmet, you should release it, and besides, if you don’t someone else will.
b) Recommend continued testing until your company’s product is at least as good as
the worst competitor’s product.
c) Contact your company’s legal department to warn them of a potential product
liability problem and ask for their advice.
d) Go over the Vice President’s head and explain the problem to the company’s
President.
1) Apply the Fundamental Canons: Engineers, in the fulfillment of their professional
duties, shall:
1) Hold paramount the safety, health, and welfare of the public - this canon
supports doing options b), c), or d).
2) Perform services only in the area of their competence - applies equally
to all options.
3) Issue public statements only in an objective and truthful manner applies equally to all options - no public statement has been made yet.
4) Act for each employer or client as faithful agents or trustees—Argues
strongly against option a) - signing off on an inferior product is not
faithful service.
5) Avoid deceptive acts - again, argues against option a) which is
deceptive.
6) Conduct themselves honorably, responsibly, ethically, and lawfully so as
to enhance the honor, reputation and usefulness of the profession - This
canon argues in favor of options b), c), and d).
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2) Engineering Ethics Matrix:
Options
Canons
Hold
paramount
the safety,
health and
welfare of
the public.
Perform
services
only in the
area of your
competence
Issue public
statements
only in an
objective
and truthful
manner
Act for each
employer or
client as
faithful
agents or
trustees
Avoid
deceptive
acts
Conduct
themselves
honorably
…
b)
Recommend
continued
testing
Meets canon
c) Contact
legal
department
d) Go over
superior’s
head
Meets
canon
Meets canon
Meets canon
Meets canon
Meets canon
Meets canon
Release may
be an
implicit
untruthful
statement
Meets canon
Meets canon
Meets canon
You are
subjecting
your
employer to
liability- so
does not
meet canon
Deceptive
Meets canon
Meets canon
Meets canon
Meets canon
Meets canon
Meets canon
Meets canon
Avoiding
responsibility
is
dishonorable
Meets canon
Meets canon
a) Release
helmet
Does not
meet canon
Solution: The canons rule out option a) - whatever the Vice President of
Sales says. The choice among options b), c) and d) depends on which
would most effectively insure public safety, as each represents acting as a
faithful agent to the employer.
Copyright ©2010, Elsevier, Inc
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468
14-20) During World War II, Nazi Germany conducted human medical experimentation
on large numbers of people held in its concentration camps. Because many German
aircraft were shot down over the North Sea, they wanted to determine the survival time of
pilots downed in the cold waters before they died of hypothermia (exposure to cold
temperatures). German U-boat personnel faced similar problems.
In 1942, prisoners at the concentration camp in Dachau were exposed to
hypothermia and hypoxia experiments designed to help Luftwaffe pilots. The research
involved putting prisoners in a tank of ice water for hours (and others were forced to stand
naked for hours at sub-freezing temperatures) often causing death.
Research in the pursuit of national interests using available human subjects is the
ultimate example of questionable bioengineering. Since the Nazi scientific data were
carefully recorded, this produces a dilemma that continues confronts researchers. As a
bioengineer today, should you use these data in the design of any product (such as cold
weather clothing or hypothermia apparatus for open heart surgery?)
a) Since these experiments had government support and were of national interest at
the time, so they should be considered valid and available for scientific use now.
b) Should you use these data since similar scientific experiments have been
conducted in other countries during periods in which national security is
threatened and these data are not questioned today. Even the US conducted
plutonium experiments on unsuspecting and supposedly terminally ill patients
(some of whom survived to old age!)
c) This is just history and should have no bearing on the value or subsequent use of
the data obtained.
d) Experimentation of any kind on unsuspecting or unwilling humans is abhorrent
and unethical and should not be tolerated under any circumstances.
Show your results in an Engineering Ethics Matrix.
1) Apply the Fundamental Canons: Engineers, in the fulfillment of their professional
duties, shall:
1) Hold paramount the safety, health, and welfare of the public - if the data
provided by these tests is unobtainable by other means, this would
argue in favor of option c (“use the data”).
2) Perform services only in the area of their competence - applies equally
to all options.
3) Issue public statements only in an objective and truthful manner applies equally to all options.
Copyright ©2010, Elsevier, Inc
Kosky, Wise, Balmer, Keat: Exploring Engineering, Second Edition
4) Act for each employer or client as faithful agents or trustees - applies
equally to all options.
5) Avoid deceptive acts - applies equally to all options.
6) Conduct themselves honorably, responsibly, ethically, and lawfully so as
to enhance the honor, reputation and usefulness of the profession - this
canon reminds us that human ethics can override narrowly
professional ethics. In this case human ethics clearly does override
narrowly professional ethics. Deliberately sacrificing one human life
against the will of that human for the benefit of another human (or
even for the benefit of billions of other humans) is unethical. This
argues for option d) (which implies “don’t use the data”).
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2) Engineering Ethics Matrix:
Options
Canons
Hold
paramount
the safety,
health and
welfare of
the public.
Perform
services
only in the
area of your
competence
Issue public
statements
only in an
objective
and truthful
manner
Act for
each
employer or
client as
faithful
agents or
trustees
Avoid
deceptive
acts
Conduct
themselves
honorably
…
a) Treat as
valid
b) Use data
c) Ignore
source of
data
d) Do not
use data
Meets
canon
Meets
canon
Meets
canon
Does not
put safety
paramount
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Meets
canon if
done
thoughtfully
and with
attention to
possible
public
reaction
Meets
canon
Risks
ignoring
damage to
employer’s
reputation
Risks
ignoring
damage to
employer’s
reputation
Meets
canon
Meets
canon
Meets
canon
Meets
canon
Risks
dishonoring
profession
by ignoring
ethical
issues
beyond the
canons
Risks
dishonoring
profession
by ignoring
ethical
issues
beyond the
canons
Meets
Clearly
canon
dishonors
profession
by ignoring
ethical
issues
beyond the
canons
Copyright ©2010, Elsevier, Inc
Kosky, Wise, Balmer, Keat: Exploring Engineering, Second Edition
Solution: In this case, canon 6 speaks so strongly to the issue that it is hard
to conceive of it being overruled by canon 1, in spite of that word
“paramount”. The canons therefore argue for option d, don’t use the data.
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