Engineering - Learning from the Past and Building the Future
Oct 28, 2014
“Bad decision making can overcome even robust engineering”.1 Expectations of society towards mechanical engineers include that the product will fulfil its purpose, address the need, and do so in a way that doesn’t do any harm. In that respect it is an engineer’s priority to keep the potential for human error to a minimum by making sure that a newly designed mechanism has been thoroughly tested prior to entering the market. By examining incidents of mechanical failures from the early 20th century until today, this paper shows how learning from past mistakes plays a crucial role in designing a better and safer world for the future.
Henry Ford would have fit pretty well into my former perception of a typical engineer. When he wanted to build his famous V-8 motor, his engineers told him that it would be an impossible task. Ford however, told them to ''Produce it anyway.”2 Is that what engineering is all about – the creation of products that have never existed before? In fact, it was Léon Levavasseur who had constructed the first V-8 engine for the aircraft industry thirty years earlier, in 1902.3 Furthermore, before Ford’s V-8 was introduced, high-end automobiles were already equipped with V-8 cylinders. 4 Consequently, Ford’s aim was not to produce a new product that never existed before – he wanted to make an existing product more competitive, by decreasing its costs of manufacturing and making it available to a wider range of people. Since Ford was determined to get the product into the market by 1932,5 he did have little time to test drive his new engine. As a consequence, nearly every part of the engine experienced some issue and had to be replaced.6
This is only one example that illustrates the importance of making sure that a product is working without any problems before introducing it into the market. Not only does it mean that manufacturers will have to deal with fewer customer complaints, but most importantly, it ensures that users are safe. Engineers often find themselves in two unfortunate situations. One is engineering error or failure as one of the first speculations made when an accident occurs. Two is engineering failures (even if they are only assumptions) get much more media coverage than products that are well designed and serve their purpose. The following incident illustrates these points in more detail.
Today, the John Hancock Tower in Boston is rated as the “third-best work of architecture in the Boston history.”7 However, the public perception was very different in the 1970s when the 62-story, approximately 1,700,000 square foot tall glass tower8 was still under construction and at least 65 huge panels of glass, each weighing 500 pounds, smashed onto the ground reaching up to 75 miles per hour.9 Both the architecture company I.M. Pei and Partners, as well as the engineers working on the project, were subject to criticism for having made a mistake in the construction of the building. After several years of negative press, experiments conducted with the Hancock window panels showed that it was the window maker who hadn’t produced the correct type of glass. All 10,344 windows of the Hancock Tower had to be replaced by the manufacturer for a total cost of $7 million.10 But the reputational damage to architects and engineers was already done.
This incident illustrates just how easy it is for engineers to be in the center of the news as soon as something seems to have failed. Since a train or plane accident gets much more media coverage than a car accident, some people even believe that air travel is riskier than other means of transportation.11 In fact, driving a car is the most dangerous means of transportation, whereas travelling by train is the safest.12 But why is it so easy to connect engineers with whatever seems to be out of control? One part of the answer is that engineering is involved in nearly everything we interact with in our daily lives. The other part of the answer is that engineering products is a process that consists of many different stages that are fulfilled by more than one person – hence, there is increased potential for errors to occur. A study conducted at the Swiss Federal Institute of Technology in Zurich analyzed 800 cases of engineering failures in which 504 people were killed, 592 people injured, and millions of dollars of damage incurred.13 Some engineering failures can be explained by a lack of sufficient test runs, however, sometimes it is much more difficult to foresee and more importantly to imitate all potential environmental conditions.
When the Titanic made her maiden voyage in 1912, it was the “largest moveable object ever made”.14 One reason for the rapid sinking of the ship was due to the underestimation of environmental influence and the choice of material. The hull steel and the wrought iron rivets failed due to brittle fracture.15 Factors that lead to brittle fracture include low temperature, high impact loading and high sulphur content, which were all present on the day when the Titanic hit the iceberg and sunk.16 In addition, the ship that even “God himself could not sink […]”17 had design flaws, which became apparent when the water that entered the front six so-called “watertight compartments” began to spill over into adjacent compartments.18 In fact, the compartments were only “watertight” horizontally; their tops were open, so that the water could flow from one compartment to the next.19 The most tragic element of the disaster is the fact that passenger’s lives could have been saved, if there had only been enough lifeboats. The Titanic had only 20 lifeboats on deck, but 48 would have been needed to save all passengers on board.20 Is this yet another example of engineering carelessness? In fact, the vessel was carrying more lifeboats than it required according to the British Board of Trade’s rules. However, these rules had been made in 1894, and the Titanic was four times larger than the largest legal classification considered under the old rules.21 In addition, due to the public belief that the Titanic was unsinkable, Titanic’s owners and the British Board of Trade thought that having too many lifeboats would unnecessarily crowd the deck and make people belief that the ship was unsafe.22 Indeed, even the car industry was reluctant to install seatbelts in the 1950s, because it gave the impression that something might be unsafe about the car.23 Had the engineers underestimated their duty to design safe and efficient mechanisms?
To conclude, although it is an engineer’s highest priority to design mechanisms that are safe, engineering errors can happen due to a number of various factors. It is an engineer’s responsibility to ensure that people’s lives are not endangered even in the event of an accident. Examples include higher safety practices and improved emergency equipment, such as airbags in cars and planes, life jackets and lifeboats on marine vessels and safety windows in busses. However, there is one risk factor that cannot be eliminated, namely human fallibility.24 As noted in an article published after the sinking of the Titanic, the Titanic "simply furnished another example of the well-established principle that if, in the conduct of any enterprise, an error of human judgment or faulty working of the human senses involves disaster, sooner or later the disaster comes.”25 In that regard, engineers cannot prevent every disaster from happening, but their task is to keep damage to human life and the environment to a minimum while creating products that solve society’s needs.
References: 2014-Miller-Williston Abstract-References