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16-13) 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
16-14) 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
16-15) 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.
Need: GSI = ____ (a number)
16-16) 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?
16-17) 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.
16-18) 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 16.6 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:
Copyright ©2015, Elsevier, Inc
21
2) Engineering Ethics Matrix
Options
Canons
a) Nothing
b) Suggest
use of dead
animals
from pound
c) Suggest
use of
human
cadavers
d) Suggest
development
of
instrumented
mannequin
Hold
paramount
the safety,
health and
welfare of
the public.
Meets canon
Meets
canon
Meets canon
Meets canon
Perform
services only
in the area of
your
competence
Meets canon
Meets
canon
Meets canon
Meets canon
Issue public
statements
only in an
objective and
truthful
manner
Silence here
is an
untruthful
public
statement
Meets
canon
Meets canon
Meets canon
Act for each
employer or
client as
faithful
agents or
trustees
Risks harm
to employer’s
reputation
Meets
canon
Meets canon
Meets canon
Avoid
deceptive
acts
Does not
apply
Meets
canon
Meets canon
Meets canon
Conduct
themselves
honorably …
Not
honorable in
disregard for
issues of
animal
welfare
Meets
canon
Meets canon
Meets canon
Solution: The ethical problem comes down to balancing canon 1 and
canon 6. Is the potential payoff in terms of human health and safety
Kosky, Balmer, Keat and Wise: Exploring Engineering, Fourth Edition
Copyright ©2015, Elsevier, Inc
22
16-19) 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:
2) Engineering Ethics Matrix:
Options
Canons
a) Release
helmet
b)
Recommend
continued
testing
c) Contact
legal
department
d) Go over
superior’s
head
Hold
paramount
the safety,
health and
welfare of
the public.
Does not
meet canon
Meets canon
Meets
canon
Meets canon
Perform
services
only in the
area of your
competence
Meets canon
Meets canon
Meets canon
Meets canon
Issue public
statements
only in an
objective
and truthful
manner
Release may
be an
implicit
untruthful
statement
Meets canon
Meets canon
Meets canon
Act for each
employer or
client as
faithful
agents or
trustees
You are
subjecting
your
employer to
liability- so
does not
meet canon
Meets canon
Meets canon
Meets canon
Avoid
deceptive
acts
Deceptive
Meets canon
Meets canon
Meets canon
Conduct
themselves
honorably
…
Avoiding
responsibility
is
dishonorable
Meets canon
Meets canon
Meets 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.
16-20) 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 crew 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:
Copyright ©2015, Elsevier, Inc
26
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”).
2) Engineering Ethics Matrix:
Options
Canons
a) Treat as
valid
b) Use data
c) Ignore
source of
data
d) Do not
use data
Hold
paramount
the safety,
health and
welfare of
the public.
Meets
canon
Meets
canon
Meets
canon
Does not
put safety
paramount
Perform
services
only in the
area of your
competence
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Issue public
statements
only in an
objective
and truthful
manner
Does not
apply
Does not
apply
Does not
apply
Does not
apply
Act for
each
employer or
client as
faithful
agents or
trustees
Meets
canon if
done
thoughtfully
and with
attention to
possible
public
reaction
Risks
ignoring
damage to
employer’s
reputation
Risks
ignoring
damage to
employer’s
reputation
Meets
canon
Avoid
deceptive
acts
Meets
canon
Meets
canon
Meets
canon
Meets
canon
Conduct
themselves
honorably
…
Risks
dishonoring
profession
by ignoring
ethical
issues
beyond the
canons
Risks
dishonoring
profession
by ignoring
ethical
issues
beyond the
canons
Clearly
dishonors
profession
by ignoring
ethical
issues
beyond the
canons
Meets
canon
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.
