978-0128012420 Chapter 16 Part 2

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:

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

Perform

services only

in the area of

your

competence

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

Act for each

employer or

client as

faithful

agents or

trustees

Risks harm

to employer’s

reputation

Meets

canon

Meets canon

Avoid

deceptive

acts

Does not

apply

Meets

canon

Meets canon

Conduct

themselves

honorably …

Not

honorable in

disregard for

issues of

animal

welfare

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

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

Issue public

statements

only in an

objective

and truthful

manner

Release may

be an

implicit

untruthful

statement

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

Avoid

deceptive

acts

Deceptive

Meets canon

Conduct

themselves

honorably

…

Avoiding

responsibility

is

dishonorable

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:

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.