Product fragility is measured on a vibration tester which is able to make either sinus vibrations in a sweep (different hz and amplitude) or random vibration. Many prefer to test own frequencies in a sinus sweep.
The product is mounted at the vibration table. The table is running a sinus sweep (harmonious sinus vibrations with a slowly change in frequency). The sweep starts at the lowest possible frequency and runs up to a maximum level of 100-200 Hz. Do you expect to use corrugated boxes you have no need to test over 100 Hz because the natural frequency of corrugated boxes is about 80 Hz. The energy in the input is constant during the sweep.
An accelerometer mounted on the product measures the product output. The signal from the table (input) is compared with the output. If the 3 peaks in the output are higher than the input it is critical for the product in case of such frequencies in the distribution. Also a small peak lower than the input can be a problem. Compare such a response diagram me with the spectra from truck, train, ship and airplane transport.
You can analyse the response from the product only by using your ear and listen to sounds from the product. When you hear sounds from the product note the frequency. You can also use an accelerometer on the product and compare inputs and outputs as illustrated.