First Experience in Uncovering the Truth Behind a Case

In January 2017, while serving as a faculty member at the College of Engineering at UL Lafayette, I was approached by a colleague who needed help with a case involving an unexpected damage charge. At the time, I was not acting as a paid expert witness; I simply lent my engineering knowledge to help uncover the truth.

My colleague had stayed at a hotel in Washington, DC, from January 7 to January 13, 2017, while attending a conference. After checking out, he didn’t receive a receipt and was told it would be sent via email. Days later, he received a guest folio with an unexpected charge of $1,594 for a "damaged dining table." The hotel also sent him a photo of the damaged table, which showed a stone tabletop supported by a metal frame. The damage, curiously, was located on the bottom corner edge of the table. My colleague reached out to me, knowing I could use my expertise to determine whether the damage was truly his responsibility.

Analyzing the Evidence

Upon reviewing the picture of the damage, several details stood out. The table appeared to have a stone top, likely limestone, supported by a sturdy metal frame. Typically, a stone tabletop would fail at the upper corner edge if struck, as this is the most vulnerable point when dealing with brittle materials like stone. However, in this case, the damage was primarily located on the bottom corner edge, which was unusual.

Given these observations, I began conducting a theoretical stress analysis, assuming the tabletop was made of homogeneous material. This involved evaluating the distribution of principal stresses and angles across the table’s structure. My analysis revealed that under normal conditions, failure would occur at the top edge if the tabletop were subjected to an external force, such as a direct hit. The lower edge, on the other hand, would typically remain intact, as it would be less susceptible to impact damage from common forces.

With this knowledge, I began to question how the damage could have occurred. I hypothesized that two factors could explain the failure:

(1) Pre-Stress After Assembly

If the table had been improperly assembled, with either excessive tightening or insufficient support from the metal frame, it could create pre-stress within the stone top. Over time, this pre-stress could lead to the formation of micro-cracks, particularly along the weaker, lower edge. As these cracks propagated, they would eventually cause the material to fail at the bottom edge—exactly as seen in the picture. I also observed a pre-existing crack in the photo, further supporting this theory.

(2) Discontinuity in Microstructure

Another potential cause of the failure was the presence of different phases within the stone’s microstructure. In materials science, discontinuities between phases can lead to internal stress concentrations, which, when combined with external loads, can initiate micro-cracking. Over time, especially under the weight of the tabletop or through daily use, these cracks would propagate and lead to a larger fracture. In this case, pre-stress from improper assembly could accelerate the aging process, making the tabletop more prone to damage even under regular service conditions.

Building the Case

Based on my analysis, I concluded that the damage to the table was not caused by any external impact but was likely the result of inherent design or assembly flaws. The micro-cracks observed and the unusual location of the failure strongly pointed to this being a maintenance issue, rather than something my colleague was responsible for during his stay.

I compiled my findings into a detailed four-page report, explaining the mechanics of the failure and my reasoning behind the conclusions. I provided a thorough breakdown of how both improper pre-stress and microstructure discontinuities could lead to the observed damage, ultimately suggesting that the hotel should have performed better maintenance or quality control during assembly.

Results of the Investigation

A few weeks after the report, my colleague contacted me with good news: he had successfully contested the charge. The hotel not only waived the $1,594 damage fee but also provided him with compensation. This marked my first foray into expert witness work, and it was a rewarding experience to see how engineering analysis and critical thinking could unravel the truth behind a seemingly straightforward dispute.