Responses On Large Span Spherical Reticulated Shells Under Impact Loads

With the continuous development of economy, large span reticulated shells in construction engineering have received more and more widely used in practice. At the same time, the chances of reticulated shell structure subjected to impact load is relatively large. Due to the impact load has the characteristic of short duration, high peak value, which may causes huge and immeasurable losses and extremely serious negative effects to people's psychology. With the constant improvement of computer technology, it is possible to research on resistance of reticulated shells under impact load by numerical algorithm. In the field of reticulated shell shock, on the basis the span of reticulated shells of previous scholars research are smaller, which are limited to single layer reticulated shells, this cannot satisfy the actual engineering practice of large span reticulated shells, this article will research the impact resistance of large span reticulated shell in this background, and the main contents are as follows:1. Single-layer spherical reticulated shells and double-layer spherical reticulated shells models are foundedThis article describes the basic theory of the software for solving the impact problem in the environment of the finite element analysis software ANSYS/LS-DYNA. By defining the proper element type, material properties, basic assumptions are put forward, it will establish a reasonable simulation method of single-layer spherical reticulated shells and double-layer spherical reticulated shells under all kinds of impact load characteristics.2. Influence on failure modes for reticulated domes impacted by impactors with different sizes and material attributesThis article researches the changing law of failure modes with the change of the impactors' material attributes and size are also analyzed. In accordance with the relationship between energy absorption and failure modes in previous studies, the effect on failure modes subjected to the different sizes and the material of impactors is analyzed.3. Impact dynamic response and failure law of large span spherical reticulated shellsCombining with three typical examples, these kinds of failure modes of the spherical reticulated shell were given, and their characteristic of dynamic response was also analyzed. The difference of failure modes under different conditions is analyzed and explained, these condition contains the different roof loads, spans and bar cross sections.4. Evaluation of spherical reticulated shell impact resistant ability by a new methodBased on the changing of the critical impact kinetic energy, synthetically considering the transforming regular between different impact response modes, found out that the impact response modes change regularly with the kinetic energy carried by the impactors.