In　civil　engineering,　concrete　structures　often　suffer　from　multiple　dynamic　loadings,　or　being　subject　to　dynamic　loadings　with　different　strain　rates　on　the　base　of　initial　loadings.　In　the　study,　a　three-dimensional　meso-scale　numerical　model　of　dumbbell-shaped　concrete　was　established.　The　uniaxial　dynamic　tensile　failure　behavior　of　concrete　materials　under　different　nominal　strain　rates　was　simulated.　The　sudden　increase　of　strain　rate　in　the　hardening　and　softening　stages　of　a　concrete　uniaxial　tensile　stress-strain　curve　were　also　simulated　in　meso-scale.　The　effects　of　the　sudden　increase　of　strain　rate　on　the　dynamic　tensile　failure　behavior　and　stress-strain　curves　were　analyzed.　The　results　show　that　the　strain　rate　effect　of　concrete　is　relatively　weak　under　low　strain　rate,　while　the　strain　rate　effect　is　significantly　enhanced　under　high　strain　rate.　The　dynamic　tensile　strength　and　corresponding　peak　strain　resulted　in　by　loading　after　the　sudden　increase　of　strain　rate　in　the　hardening　stage　are　significantly　enhanced.　When　the　sudden　increase　of　strain　rate　happens　in　the　softening　stage,　the　＇softening　behavior＇　changes　to　the　＇hardening　behavior＇,　and　a　secondary　peak　appears　on　the　stress-strain　curve.　The　dynamic　tensile　strength　obtained　under　combined　loadings　of　initial　strain　rate　and　sudden　strain　rate　is　lower　than　that　obtained　under　single　loading　of　sudden　strain　rate,　and　the　percentage　of　the　decrease　in　strength　increases　with　the　increasing　strain　rate.　©　2021,　Editorial　Office　of　Journal　of　Vibration　and　Shock.　All　right　reserved.