<p>In this study, fracture analysis of thermally induced cracks in porous functionally graded (PFG) structures is carried out using extended isogeometric analysis (XIGA) under the mechanical and thermomechanical loading conditions. Multiple porosity distribution functions (PDFs) are modeled in the FG structures, and appropriate enrichment functions are utilized to represent discontinuities along the crack face while effectively capturing the singular behavior at the crack tip. Firstly, three distinct porosity distribution types—right end enhanced (REE), left end enhanced (LEE) and symmetrically center enhanced (SCE)—are incorporated into the functionally graded (FG) structure. A power law function is employed to describe the variation of material properties along the structure’s length, facilitating a gradual transition from a metal-rich region to a ceramic-dominant composition. The influence of porosity is integrated into this power law through an additional porosity term. The equivalent properties of the PFG structure are estimated along its length for various PDFs. Subsequently, an adiabatic crack is modeled within the domain to investigate its effect on the fracture behavior of FG structure under thermomechanical load using XIGA. This study introduces a novel approach by analyzing a PFG structure with an adiabatic center crack, considering various porosity distributions (LEE, REE, and SCE) under both mechanical and thermomechanical loading. To verify the accuracy of the XIGA method, the results obtained for a non-porous FG structure are compared with the existing results available in the literature under mechanical and thermal load separately. The impact of various porosity distributions on the fracture behavior of FG structure is further explored for both mechanical load and thermomechanical loading scenarios. Additionally, the effects of power law index, porosity parameter, and crack length on the fracture behavior of PFG structure are examined.</p>