Formost strip-like plastic injectionmolded parts

whose cross section size is much smaller than their length

the traditionalHele-Shawmodel and three-dimensionalmodel do notworkwell in the prediction of thewarpage because of their special shape. A newsolutionwas suggested in thiswork. The strip-like plastic partwas regarded as a little-curved beam macroscopically

and was divided into a few one-dimensional elements. On the section of each elemental node location

two-dimensional thermal finite element analysis was made to obtain the nonuniform thermal stress caused by the time difference of the solidification of the plastic melt in the mold. The stress relaxation

or equivalently

strain creep was dealt with by using a special computing model. On the bases of in-mold elastic stress

the final bendingmoment to the beamwas obtained and thewarpagewas predicted in good agreement with practical cases.