Could Crash Modeling Have Saved the Concordia?8 Mar, 2012 By: Robert Yancey
Viewpoint: Event simulation helps automobile manufacturers design safer vehicles — and it can do the same for shipbuilders.
The Costa Concordia cruise ship disaster has generated many questions, but one in particular haunts survivors and onlookers alike: Could this disaster have been prevented? It is clear that the captain made some unwise choices, which put the ship and its passengers in danger. Could something have been altered in the ship’s design to limit the impact of that poor decision-making on the crew and passengers?
Most automobile accidents are also caused by bad decisions. Some are caused by conditions beyond the control of the driver, but the vast majority are a result of drivers speeding, disobeying traffic regulations, attending to distractions, falling asleep at the wheel, etc. Automotive manufacturers have done a great deal to improve car safety, introducing features that minimize harm even when drivers perform poorly. Crumple zones, airbags, and energy-absorbing materials all reduce passenger injuries and fatalities in crashes. Automobile safety ratings for the past decade show a clear improvement — much of which is due to extensive simulation modeling of crash events.
In simulation modeling, engineers use a digital design of a vehicle to generate a simulation model that represents all of the key elements of the design, including material properties, mass properties, occupant models, and the impact event (e.g., side impact, frontal offset, etc.). Engineers have been working for years to correlate these simulation models with real-world test results. The result is that modern simulation models correlate very well with physical test data in regard to the deformation of the vehicle, the energy absorption of the vehicle, and — most importantly — the effects on the passengers.
The accuracy of these models is now so high that most automotive companies do extensive virtual testing of their vehicle designs before ever building prototypes, and the physical testing is really just a final verification of the crashworthiness of the design. In most cases, there are no surprises during the physical test.
From Land to Sea
Could ship designers follow the automotive industry's example? Could we employ simulation modeling to create more advanced designs that can better respond to the type of event that destroyed the Concordia? The answer is yes.
Engineers could use much of the technology developed for automotive crash modeling to model a ship’s impact on rocks, icebergs, sandbars, and other hazards. We cannot always prevent these events from happening, but if we can develop ship designs that more effectively respond to these impacts — especially to provide sufficient time to safely evacuate the passengers — we could improve passenger safety and confidence.
In the case of the Concordia, the ship’s hull was divided into several watertight compartments; one or two sections of the hull could flood without sinking the entire ship. The ship had longitudinal bulkheads, intended to keep it from listing when flooded. During the recent disaster, however, the ship came to rest on a rock ledge; this caused the vessel to become unstable on the uneven bottom and roll on its side. This position complicated the rescue operation, because many of the lifeboats could not be deployed with the ship listing to one side.
Disaster simulations could help ship designers prepare for uncommon scenarios, such as having a ship run aground and roll onto its side. Image courtesy of Roberto Vongher, via Wikimedia Commons.
This occurrence, and many other unusual situations, could be simulated on a computer. Just as a car-crash simulation varies according to speed, direction, impact zone, and other elements, a good simulation model of a ship could replicate many of the conditions that the vessel might encounter. Armed with the results of these simulations, engineers can adapt the ship design to better respond to each of these situations.
Simulation Offers Proven Benefits
In addition to the automotive industry, the ability of simulation to inform design is also evident in the aviation world. Airplane designers must ensure a safety by planning for a variety of events, including excessive turbulence, engine failure, bird strikes, and lightning. Redundancy is built into the design to ensure that the airplane can land safely, even under these circumstances. Simulation modeling is also used extensively in the aerospace industry to understand and design for these events.
Can simulation modeling help with the design of cruise ships? Twenty-five years of experience in the simulation field has taught me that simulation technology definitely can help this industry. The technology is available, it's proven, and it can be used successfully to improve safety.
In that case, the questions become: Will the industry embrace this technology? Will shipbuilders see value in performing these simulations? and — more importantly — Will the passengers who book passage on these ships demand a safer experience? Hopefully, the Concordia tragedy will bring shipbuilders, cruise ship operators, and passengers together to create a better outcome the next time a bad decision or unforeseen event causes significant damage to a ship.