The first part of this two-part study introduces an approach for a numerical model of the composite manufacturing method light resin transfer moulding. Discussion of process physics and relevant literature is used to develop a coupled finite element and infusion software simulation of both the structural and flow elements of the method, with the aim of producing an accurate and comprehensive model. This theoretical overview of the model acts as a precursor to the final part of the research where results are presented and verified and a wind energy case-study application will be demonstrated.