Life-cycle assessment modelling and life-cycle assessment evaluation of a triboelement

A procedure based on digraph and matrix method is developed for modelling and evaluation of life-cycle assessment (LCA) of a triboelement. LCA parameters of a triboelement are identified and are called LCA attributes. Consideration of these attributes and their interrelations is rudiment in modelling and evaluation of LCA index. The LCA attributes of a triboelement are modelled in terms of LCA attributes digraph. The digraph is represented by a one-to-one matrix for the development of LCA expression, which is based on various LCA parameters/attributes. A variable LCA attributes relationship permanent matrix is defined to develop LCA expression (VPF-t), which is also useful in comparing two triboelements. LCA index of the triboelement is obtained from permanent of the matrix by substituting the numerical values of the attributes and their interrelations. A higher value of the index implies better LCA of the triboelement. The ideal value of LCA index (I-L(t)) is also obtained from the matrix expression, which is useful in assessing the relative LCA (I-L(t))(r) of the triboelement. The procedure is not only useful for evaluation of LCA of triboelements at operational stage, but can also be used for the design and development of a triboelement at system design stage from LCA point of view. A step-by-step procedure for evaluation of LCA index is also suggested and is illustrated by means of an example.