Three-dimensional integrated woven spacer sandwich composites have been widely used as industrial textiles for many applications due to their superior physical and mechanical properties.Three-dimensional integrated woven spacer sandwich composites made of glass fiber with “8”shape and “1” shape structures in the core,having the advantages of being light weight,energy absorbent,high strength,high stiffness,and cost-effectiveness over the traditional sandwich structure composite materials.This research investigates the structural parameter changes that influence the mechanical properties of three-dimensional integrated woven spacer sandwich composites under different load conditions.As well as explore the fracture morphologies under various load conditions.This investigation aims to provide a broad description of the mechanical properties and fracture behavior of three-dimensional woven spacer sandwich composites with different structural parameters under various experimental analyses.Which can help determine the mechanical properties and structure of three-dimensional integrated woven spacer sandwich composite materials for end-use products.The comprehensive study focused on the 3D woven sandwich structure composites,mainly three-dimensional integrated woven spacer sandwich composites.The reinforcement 3D integrated woven spacer fabric was made of high-performance alkali-free glass fiber.Five different specifications 3D integrated woven spacer sandwich composites were developed by using the hand lay-up technique.Structural parameters including core piles height,core shape,face sheet thickness,warp,and weft directional influence on the 3D integrated woven spacer sandwich composites studied under three-point bending load,edgewise compression load,flat compression tensile load,and drop weight impact load.As well as the fracture morphologies of the three-point bending fractured specimen,edgewise compression fractured specimen,and tensile test fractured specimen was analyzed by XR-CT（X-ray computed tomography）.XR-CT was used for the first time to visualize the microstructural details and fracture morphologies of 3D integrated woven spacer sandwich composites.No previous research has explored this method to analyze 3D integrated woven spacer sandwich composites.Moreover,the damage morphologies of 3D integrated woven spacer sandwich composites under different impact energies were analyzed by simple visualization of the specimen.It was found that the core height,face sheet thickness,fiber strength,warp,weft structure,and resin impregnation significantly influenced the mechanical properties and performance of 3D integrated woven spacer sandwich composites.The bending result demonstrated that the low core height structure has better bending strength due to the “8” shaped structure and the action of the resin matrix.Meanwhile,the bending strength and anti-deformation ability were more significant for the weft direction than the warp direction.The core piles height considerably influenced the thickness of the flatwise and edgewise compression properties.Compression properties decreased with the increase of core piles height.The warp compression properties of the 3D integrated woven spacer sandwich composites were higher than the weft compression properties.Fiber strength and face sheet thickness considerably affected tensile failure and properties.Moreover,the core pile height had a dominant impact on the tensile properties and performance of warp and weft direction structures.XR-CT images have shown different fracture morphologies such as microfiber tears,fibers twist and split,matrix and fiber interfacial debonding,fiber pull out,and so on and visualize the microstructure of 3D integrated woven spacer sandwich composites.Drop weight impact test revealed that the core piles heights and diverse impact energies significantly affect the stiffness and energy absorption capacity.There has no significant influence of face sheet thickness on impact response.Overall,this study revealed that the structural parameters of 3D integrated oven spacer sandwich composite significantly influence mechanical properties and performance.The data presented in this research have added a new dimension in the research and development of 3D integrated woven spacer sandwich composites.The major influencing factors and their effects are clarified throughout this research.Further investigation and improvement in designing,development and damage modes are still required to obtain the heights performance and ensure the idle use of 3D integrated woven spacer sandwich composites.