To obtain the effect of different parameters on the tensile performance of stepped-lap repaired composite laminates

the repaired specimens were investigated experimentally. In terms of the laminates with 8 plies

stepped-lap repaired specimens with 2

4 and 8 steps were tested

respectively. In addition

the stepped-lap joint with 4 steps was studied with different number of external plies. As a comparison

a tapered scarf repair with the same bonding area was also tested. Results showed that the tensile strength of stepped-lap repairs increased with increasing the number of steps. When the number of steps increased from 2 to 8

the strength recovery rate of the repaired joint increased from 36% to 67%. The introduction of external plies could also improve the efficiency of repairs. However

the dispersion of the repair strength increased with the increase of external plies. As the stress distribution in the adhesive film is more uniform for the tapered scarf joint

its repair strength is higher. Compared the stepped-lap repaired joint with the tapered scarf joint with the same bonding area

the repair efficiency of the latter is higher. Take the 4 stepped-lap repaired joint for example

its repair strength is increased by 25% compared with that of the tapered scarf joint. Finally

according to the stress/strain distribution on the surface of the repaired joints

the failure mechanism and failure process of the repaired joints under tensile load were obtained.