Abstract: Continuum damage mechanics (CDM) models have been employed successfully in the literature to predict the response of laminated composite materials. Some sophisticated models can include the effects of non-linear shear and transverse damage progression, plasticity and shear-transverse damage coupling. However, these models require non-standard test data for calibration that may not always be available to a modeller. In this two-part study, we examine the effect of neglecting plasticity parameters, and also the effect of neglecting both plasticity and shear-transverse coupling parameters in simplified CDM models for predicting monotonic tensile strength. In part I, we develop simplified versions of the CDM model and test their ability to accurately predict the failure response of angle-ply laminates. In part II, we provide details of the experimental test series carried out to determine the input parameters for the models. It was found that neglecting plasticity requires some approximations in the damage development laws, but the resulting model can predict well the response of the angle-ply laminates tested under monotonic loading to failure. Neglecting shear-transverse coupling is acceptable for the some materials.