Complex product development will inevitably face the design planning of the multi-coupled activities,and overlapping these activities could potentially reduce product development time,but there is a risk of the additional cost.Although the downstream task information dependence to the upstream task is already considered in the current researches,but the design process overall iteration caused by the information interdependence between activities is hardly discussed;especially the impact on the design process’ overall iteration from the valid information accumulation process.Secondly,most studies only focus on the single overlapping process of two activities,rarely take multi-segment and multi-ply overlapping process of multi coupled activities into account;especially the inherent link between product development time and cost which originates from the overlapping process of multi coupled activities.For the purpose of solving the above problems,as to the insufficiency of the accumulated valid information in overlapping process,the function of the valid information evolution(VIE) degree is constructed.Stochastic process theory is used to describe the design information exchange and the valid information accumulation in the overlapping segment,and then the planning models of the single overlapping segment are built.On these bases,by analyzing overlapping processes and overlapping features of multi-coupling activities,multi-segment and multi-ply overlapping planning models are buiby sorting overlapping processes and analyzing the construction of these planning models,two conclusions are obtained:(1) As to multi-segment and multi-ply overlapping of multi coupled activities,the total decrement of the task set development time is the sum of the time decrement caused by basic overlapping segments,and minus the sum of the time increment caused by multiple overlapping segments;(2) the total increment of development cost is the sum of the cost increment caused by all overla
展开▼