Method for calculating load coefficient of uniform cross-section and simply-supported beam under action of blast load

Abstract

The invention discloses a method for calculating a load coefficient of a uniform cross-section and simply-supported beam comprising near-field blast and far-field blast. The method comprises the stepsof: firstly, establishing a uniform load model of a uniform cross-section and simply-supported beam under the action of near-field blast and far-field blast, and establishing a coordinate by taking the mid-span position of the uniform cross-section and simply-supported beam as the coordinate origin, the horizontal rightward parallel beam direction as the x axis direction and the direction vertical to the x axis direction as the y axis direction; and, selecting the mid-span cross section of the uniform cross-section and simply-supported beam as an observation position, wherein constraint conditions of two end parts of the uniform cross-section and simply-supported beam are same, solving a first-order vibration mode function by adopting Taylor's third-order substitution, selecting a typicalblast impact wave overpressure peak parameter value and an explosive equivalent, and thus, determining the blast load coefficient of the uniform cross-section and simply-supported beam comprising near-field blast and far-field blast. A uniform calculation formula obtained by the method can provide relatively accurate calculation numerical value for structural design calculation; and the design risk due to ignoring of the near-field blast in the traditional method can be reduced.

Description

technical field [0001] The invention relates to a method for calculating the load coefficient of a simply supported beam of equal section under the action of an explosion load, belonging to the technical field of explosion-proof design of structural engineering. Background technique [0002] At present, when the equivalent single-degree-of-freedom design calculation of the equal-section simply-supported beam structure under the action of explosion is carried out at home and abroad, the explosion shock wave load factor is calculated using uniform load, that is, the premise is a far-field explosion, and the equal-section simply-supported beam is ignored. The actual situation of the near-field explosion type of the structure occurs, and when the near-field explosion occurs, the shock wave load coefficient still uses this ideal model, which will cause the calculated values ​​in the structural design calculation to be inconsistent with the actual situation. [0003] Therefore, fo...

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Problems solved by technology

[0002] At present, when carrying out equivalent single-degree-of-freedom design calculations for structures with constant-section simply supported beams under explosion, uniformly distributed loads are used in the calculation of blast shock wave load coefficients. The actual situation of near-field explosion occurs in the structure, and the shock wave load coefficient still uses this ideal model when the near-field explosion occurs, which will cause the calculated value during the structural design calculation to be inconsistent with the actual situation

[0003] Therefore, for the design of some important building structures and anti-blast experiments, in order to accurately calculate the explosion load and ensure the rationality of the structural design, it is necessary to obtain a unified calculation formula or load factor that includes the load coefficients of near-field explosions and far-field explosions Look up the table to reduce the design risk caused by ignoring near-field explosions, but the current design methods and research results have not effectively solved this problem

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