1. A method of selecting sampling points in a sequential multi-objective engineering design optimization of a product based on the product's durability in response to an impact event, said method comprising: (a) receiving a description of the product to be optimized; (b) selecting an initial set of sampling points in a design variable space configured for evaluating durability of the product in response to an impact event; (c) obtaining numerically-simulated structural responses by conducting a computer simulation of the impact event for each of the currently-selected set of the sampling points; (d) constructing metamodels using the numerically-simulated structural responses and deriving one or more approximate Pareto Optimal Points (POPs) from said metamodels; (e) selecting one or more Pareto Optimal Frontier (POF) kernels from said one or more approximate POPs with a first point selection procedure that maximizes minimum distance amongst the selected POF kernels; (f) establishing one or more subregions encasing the respective POF kernels, each subregion being associated with a size; (g) creating a set of Diversity Basis Points by populating said subregions according to a space filling criterion; (h) selecting another set of sampling points from a combined group of the set of Diversity Basis Points and the POF kernels using a second point selection procedure that maximizes minimum distance amongst the currently-selected set of sampling points; and (i) reducing the size of said subregions and repeating (c)-(h), until a termination condition has been reached and the currently-selected set of sampling points represent optimal designs of the product.