On the basis of the strain energy coupled with damage and within the framework of thermodynamics, a model for predicting the properties of fragmentation in brittle solids under high-rate loading is formulated in this paper. The model provides a direct, explicit and quantitative method to determine the average fragment size generated by crack coalescence and the fragment ejection velocity in the dynamic fragmentation process. The theoretical predictions of the fragment size are compared with the experimental data, and it is found that the predicted values agree reasonably well with the test results. The dependence of the ejection velocity on the strain rate is discussed. It is concluded that the value of the ejection velocity increases with the increment of the strain rate. (C) 2004 Elsevier Ltd. All rights reserved.