A memo on Engineering Recommendation for Liberty Ships

A memo on Engineering Recommendation for Liberty Ships

To: All military members

From: mechanical engineer

Date: 1/12/2019

Subject: liberty ship engineering failure

This memo is written to address the issues that had transpired during the war against the Nazi-Germans war. Specifically, it will elucidate on the mechanical failures of the Liberty ships and recommends measures to be taken to remedy this issue and to prevent similar failures from occurring.

The context of this failure occurred in World War II. The battle of France and England against Germany amid the Second World War lead to considerable utilization of resources in the two nations, which were mostly in the form of oil, food, ammunition, and fuel (Zhang 1). Beginning in the early 1940s, neither France nor England was capable of meeting the demands themselves. In a bid to support the war against German Nazis, the US provided for both France and England, but later, on New Zealand and Australia joined the allied groups, and were fighting against the Japanese in the Pacific, with several supplies that were related to war.

Because all the supplies had to be shipped across the Pacific or the Atlantic, a massive fleet of ships was needed. However, it was apparent that the old US vessels did not have the capacity nor speed to deal with such challenges.

The conundrum thus necessitated innovations, which led to the production of more than 2700 welded lightly armed ships, vessels, as well as tankers, and the production process was not standard as they were manufactured within a short period of time. Moreover, inferior materials were used, and most critically, the design plan was in such a manner that the ships were welded instead of being riveted (“Liberty Ship Fatigue Failures” N.p).

The primary cause of the accident was primarily due to steel’s low weldability (Hideo and Hisahiro 2). In addition, some of the secondary causes of the accidents were the stress concentration because of poor designs as well as the initial welding defects. Typically, steel gets ductile fracture at extremely high temperatures, and it also undergoes brittle fractures at lower temperatures. Brittle fracture transpires under high loading rate, low-temperature, and multi-axis stress constraint conditions. Therefore, the brittle fractures, which occurred in the ships, were due to low notch toughness at lower temperatures of steel at the joint that was welded, which commenced at weld cracks or points of stress concentration. The residual stresses, in conjunction with the external forces, increased the fracture in the extremely low winter temperatures. This is why almost all the accidents due to brittle fractures occurred amid the winter periods.

To remedy this issue, we recommend that the notch toughness should be increased at low temperatures. We also recommend that metallurgical improvements like low carbonization or the addition of deoxidizing elements like silicon and Manganese in order to avert the weld cracks. Moreover, changes can be made to remedy the poor designs that promoted failure. One of the designs can entail redrawing the plans to round off the troublesome hatch corners. The second design requires the installation of crack-arresting devices, to avert cracks from spreading through to the hulls. Some of the countermeasures that can be utilized are the utilization of high weldability steels in a bid to guarantee notch toughness at low temperatures. This will ensure that the vessels will be able to handle low temperatures. Kindly put these recommendations into consideration.