Micron and submicron particles tend to form agglomerates due to adhesive and cohesive forces. The disintegration of these dry powder agglomerates often represents a major task in powder technology. One model describing the mechanical stability of granulates is given by the planar fracture model of Rumpf. In the present work, a new model is introduced intended for applications where a complete disintegration of dry powder agglomerates is required (e.g. for pharmaceutical aerosol generation). Therefore, the breakup of every single connection inside an agglomerate is considered and the dispersion strength sigma(disp) of model agglomerates is calculated and discussed. In order to balance the stability of agglomerates predicted from the model with the stress which is required for powder dispersion, mechanisms of deagglomeration in fluids are discussed. Furthermore it could be shown from an example of a dry powder disperser, that a step-wise disintegration is most likely which can also be described by the model. (C) 2010 Elsevier B.V. All rights reserved.