Spectral fatigue, PSD, Transport, Condensing Units
Transportation is a factor of paramount importance on the life cycle of manufactured goods. Components are in constant movement in the production line, the product is transported to one or more distributors and then to the final costumer. During the transport, all components are subjected to vibration. Such vibrations depend on several factors, like transportation method (Truck, Train, Air, …), vehicle suspension type (Spring, Air, ...), road and rails quality, etc. Due to the unknown nature of all components involved, these vibrations are usually assumed to depict random characteristics, resulting in a somewhat random stress in the components. Most of methods to evaluate fatigue are based on the load history, making them unsuitable for the product damage estimation during transportation. In this paper a frequency domain approach is used to estimate the damage in this situations. The random nature of the load is transformed to the frequency domain using power spectrum density (PSD) and a probability density function (PDF) for the resulting stress. Afterwards, with a common fatigue curve and the stress PDF the component damage is calculated. The methodology has been used to evaluate the transportation effects on condensing unit tubes based on fatigue damage.