This article presents a new model developed to investigate hyperviscoelastic behavior of elastomeric materials/polyolefin elastomers (HDPE/POE blend) under dynamic biaxial and uniaxial tensile loading. Various strain energy functions (SEF) have been used in this model, and their capability to predict hyperelastic behavior of the aforementioned materials was validated by experimental data. In the experimental part, a new dynamic tensile-loading mechanism was designed and developed to be mounted on a drop-weight impact-testing machine. As a novelty, this mechanism has the ability to perform either uniaxial or biaxial dynamic tensile tests for any type of material, especially for investigating the hyperviscoelastic behavior of materials like elastomers at various strain rates. In addition, a new hyperviscoelastic model has been developed for elastomeric material, which can predict the behavior of the material well at different strain rates. By increasing the strain rate in the dynamic biaxial and uniaxial loading, Pucci–Saccomandi and Yeoh SEF predicted the dynamic behavior of material well due to its lower root mean square error. In fact, in this case, these functions are more capable than Mooney–Rivlin, Neo-Hookean, and polynomial SEF in predicting the effect of the strain rates. In addition, the results show that Yeoh SEF performs much better than the other SEFs in predicting the material behavior in cases of dynamic biaxial and uniaxial tensile strain. The results also indicated that the newly designed mechanism was capable of performing dynamic tensile loading and extracting its accurate results and could reduce the cost of testing compared to other methods.