<p>The purpose of this research is to design and build a new fixture to perform all fracture tests in different modes. Therefore, such a fixture has been designed and built. In this study, using the new mixed-mode fracture fixture, the fracture toughness of aluminum samples in pure modes as well as I–II, I–III, II–III, and I–II–III mixed modes has been discussed. The obtained results showed that this fixture has the ability to perform tests of all fracture modes and their mixed modes. The obtained results show that the dominant mode in each mixed mode has a great impact on the force and energy required to break the samples. Finally, scanning electron microscope imaging was used to further investigate the fracture surfaces of aluminum samples on a microstructural scale, and it was shown what effect each mode had on the sample fracture surfaces, which in mixed modes, the fracture surface had the effects of all pure fracture modes in it. In the continuation of the research, the designed fixture was modeled in Ansys Workbench software, and with the practical forces obtained from the tests, the stress intensity coefficients KI, KII, and KIII, as well as shape coefficients in different modes, were obtained for this fixture. Also, the numerical simulation of the fixture was done in Ansys Workbench 19 under the effect of different forces, and the displacement was obtained, proving the efficiency of this fixture for the fracture test in mixed modes.</p>