Explosive loading factor

Several factors affect the structural performance of a building or other structure subjected to explosion loadings (Ref. 71). These factors relate to the nature of the blast wave and the structural characteristics of the building components. The primary blast wave and stmctural factors are as follows ... 

Limit state design specifications define the load factors and combinations of loads to be used for conventional loading conditions such as dead, live, wind and earthquake. However, no current limit state design specifications cover blast loading conditions. Blast loads are combined with only those loads which are expected to be present at the time of the explosion. Therefore, blast loads are not combined with earthquake and wind loads,... 

As indicated in Fig. II-5, the effective blast loading on a structure, as represented by the dynamic load factor, is strongly dependent upon the ductility capacity p (mm) exhibited by the structure. This figure is applicable provided that the natural frequencies of the structure are far from the major frequency content of the load function and therefore no significant dynamic response is excited. A structure exhibiting a ductility level of approximately 5, for example, would typically require only of the order of 33% of the load capacity of a brittle structure with the same frequency characteristics in order to survive the same explosion. 

During the transient load phase of an accidental explosion, when the shock duration is less than the time of maximum response of the structural elements, member end rotations are limited to one degree. Maximum inelastic deformation is limited to three times the member elastic limit deflection. Since this loading phase is suddenly applied, use of material dynamic increase factors based on strain rate of loading are also used. 

Shaped charge for perforating oil well casing) 55) Cook (1958), Chapter 10, "Principles of Shaped Charges , which includes History (pp 226-28) Explosive factors in cavity effect (228-29) Application to mass loading in different geometries (229-35) Detonation pressure in nonideal explosives (235-44) Mechanism of linear collapse and jet formation (244-47) Metal-... 

The relationship between loading press and charge density for commonly pressed expls is given in Table 1 (Ref 1). An approximation of the loading densities of six commonly used explosives is shown in the nomograph, Fig 5 (Ref 3). The pressure-density relationship varies somewhat from lot to lot. In addition, loading density is affected by such factors as ram clearance and increment length... 

The calculated values do not exactly agree with those obtained by experiment if the explosion takes place in a bomb, the true compositions of the explosion products are different and, moreover, vary with the loading density. In accurate calculations these factors must be taken into account. In difficult cases (strongly oxygen-deficient compounds and side reactions, such as the formation of CH4, NH3, HCN, or HCI), the only way is to analyze the explosion products. For standard values of heats of formation at constant volume or constant pressure -> Energy of Formation. 

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