A foldable device includes a housing and a foldable display device coupled to the housing. The foldable display device includes a foldable display layer, a foldable glass layer on a first side of the foldable display layer, and a sensing device on a second side of the foldable display layer. The sensing device includes a strain gauge layer. The strain gauge layer includes an array of resistors arranged on a piezoresistive substrate. Changes in resistance levels measured by the array of resistors are used to detect faults such as scratches, punctures, cracks and the like in the foldable glass layer. The foldable device may output an alert in response to detection of a fault in the foldable glass layer.