MIL-HDBK-17-3F Volume 3,Chapter 6 Structural Behavior of Joints gression of joint types which represent increasing strength capability from the lowest to the highest in the figure.In each type of joint,the adherend thickness may be increased as an approach to achieving higher load capacity.When the adherends are relatively thin,results of stress analyses show that for all of the joint types in Figure 6.2.2.1(b),the stresses in the bond will be small enough to guarantee that the adherends will reach their load capacity before failure can occur in the bond.As the adherend thicknesses increase,the bond stresses become relatively larger until a point is reached at which bond failure occurs at a lower load than that for which the adherends fail.This leads to the general principle that for a given joint type,the adherend thicknesses should be restricted to an appropriate range relative to the bond layer thickness.Because of processing considerations and defect sensitivity of the bond material,bond layer thicknesses are generally limited to a range of 0.005-0.015 in.(0.125-0.39 mm).As a result,each of the joint types in Figures 6.2.2.1(a)and 6.2.2.1(b)corresponds to a specific range of adherend thicknesses and therefore of load capacity,and as the need for greater load capacity arises,it is preferable to change the joint configuration to one of higher efficiency rather than to increasing the adherend thickness indefinitely. OUTSIDE FAMURES JOINT SHEAR STEPPED-LAP JOWNT FAILURES FAILURES SHOWN REPRESENT THE LMMIT ON EFFICIENT DESIGN FOR SHEAR FAILURES EACH GEOMETRY OINT UTSIDE TAPERED-STRAP JOINT DOUBLE-STRAP JOINT tEND STRENGTH PEEL FAILURES BENDING OF SINGLE-LAP JOINT ADHERENDS DUE TO ECCENTRIC LOAD PATH ADHEREND THICKNESS FIGURE 6.2.2.1(b)Joint geometry effects(Reference 6.2.1(n)). 6.2.2.2 Joint geometry effects Single and double lap joints with uniformly thick adherends(Figure 6.2.2.1(a)-Joints(B),(E)and(F)) are the least efficient joint type and are suitable primarily for thin structures with low running loads(load per unit width,i.e.,stress times element thickness).Of these,single lap joints are the least capable be- 6-4MIL-HDBK-17-3F Volume 3, Chapter 6 Structural Behavior of Joints 6-4 gression of joint types which represent increasing strength capability from the lowest to the highest in the figure. In each type of joint, the adherend thickness may be increased as an approach to achieving higher load capacity. When the adherends are relatively thin, results of stress analyses show that for all of the joint types in Figure 6.2.2.1(b), the stresses in the bond will be small enough to guarantee that the adherends will reach their load capacity before failure can occur in the bond. As the adherend thicknesses increase, the bond stresses become relatively larger until a point is reached at which bond failure occurs at a lower load than that for which the adherends fail. This leads to the general principle that for a given joint type, the adherend thicknesses should be restricted to an appropriate range relative to the bond layer thickness. Because of processing considerations and defect sensitivity of the bond material, bond layer thicknesses are generally limited to a range of 0.005-0.015 in. (0.125-0.39 mm). As a result, each of the joint types in Figures 6.2.2.1(a) and 6.2.2.1(b) corresponds to a specific range of adherend thicknesses and therefore of load capacity, and as the need for greater load capacity arises, it is preferable to change the joint configuration to one of higher efficiency rather than to increasing the adherend thickness indefinitely. FIGURE 6.2.2.1(b) Joint geometry effects (Reference 6.2.1(n)). 6.2.2.2 Joint geometry effects Single and double lap joints with uniformly thick adherends (Figure 6.2.2.1(a) - Joints (B), (E) and (F)) are the least efficient joint type and are suitable primarily for thin structures with low running loads (load per unit width, i.e., stress times element thickness). Of these, single lap joints are the least capable be-