An-Najah Staff

Portable products can suffer critical damage due to drop impact and thus, such load cases must be taken into account in the conceptual and detailed design phases of such products. One method explored in the current study for alleviating the peak accelerations resulting from impact is to isolate fragile components from the product housing using internal shock mounts. There is a lack of studies that address this method in a systematic and reliable manner. This paper presents an experimental and analytical study on the dynamic behaviour during impact of portable products with internal shock mounting. Using a special drop tower with guiding frame for controlled-angle free-fall drop impact, representative products are dropped at different angles and the acceleration is recorded both on the outer case and on an internally-mounted plate. A simplified analytical procedure, suitable for conceptual design purposes, is proposed for predicting the resulting dynamic response. The work affirms the suitability of guide-and-release facilities in impact experiments; additionally, it may facilitate the conceptual design for impact resistance of portable products.

Two methods are usually available for designing structures subjected to seismic loads. They are equivalent static load method and dynamic analysis method. The dynamic method of analysis is not widely used, but it may be necessary for important structures. Dynamic analysis usually has three phases, defining the expected source of earthquake, evaluating ground surface response spectra taking into account local soil properties, and applying response spectra to proposed structure to evaluate seismic forces. In this paper, the first two phases are discussed. The recent methods in evaluating the ground response that take into account soil properties are presented. This includes sources of earthquakes in Palestine and their characteristics such as earthquake magnitude, predominant period, maximum acceleration, and duration. Furthermore, this paper presents a case study for evaluating ground response spectra using computer program called Shake that may be used to evaluate ground response in Palestine. Key Words: Dynamic Analysis, Earthquakes, Ground Response, Palestine, Shake.