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Fatigue Stiffness

  1. Anastasios P. Vassilopoulos

Published Online: 20 JUL 2012

DOI: 10.1002/9781118097298.weoc081

Wiley Encyclopedia of Composites

Wiley Encyclopedia of Composites

How to Cite

Vassilopoulos, A. P. 2012. Fatigue Stiffness. Wiley Encyclopedia of Composites. 1–9.

Author Information

  1. Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

Publication History

  1. Published Online: 20 JUL 2012


Service loading of structures affects their strength and stiffness. In many cases, the influence of the stiffness changes on the structure is quite large since these changes also affect the deflections, cause dimensional changes, alter the structure's vibration characteristics, and affect the load or stress distributions inside the structure. Several generic sources of stiffness changes can be identified in various degrees. Transverse cracking, delamination, fiber breakage, and fiber-matrix debonding are some of the defects that occur in laminated composites. Stiffness changes can be used for the development of fatigue life modeling and prediction methodologies as well, since stiffness can be monitored in a nondestructive way during the operation of a structure. These subjects are discussed in this article through the demonstration of the fatigue behavior and stiffness degradation patterns of several multidirectional composite laminates and adhesively bonded composite joints.


  • fatigue;
  • stiffness;
  • failure;
  • stiffness degradation;
  • off-axis angle