The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Daining Fang - One of the best experts on this subject based on the ideXlab platform.

  • high temperature fracture toughness and residual Stress in thermal barrier coatings evaluated by an in situ indentation method
    Ceramics International, 2018
    Co-Authors: Zhaoliang Qu, Qing He, Rujie He, Shixing Wang, Daining Fang
    Abstract:

    Abstract High temperature fracture toughness and residual Stress are important for the evaluation of TBCs. In this paper, an in-situ high temperature indentation method was originally developed to investigate the high temperature fracture toughness and residual Stress in a typical TBC, nanostructured 8 wt% yttria partially stabilized zirconia (YSZ) coating. The cracks caused by in-situ high temperature indentation tests were observed, and high temperature fracture toughness and residual Stress were experimentally measured. The fracture toughness was measured to be 1.25, 0.91 and 0.75 MPa*m 1/2 at 25, 800 and 1000 °C, respectively. The residual Stress was measured to be − 131.3, − 55.5 and − 45.5 MPa, correspondingly. Moreover, the residual Stress and fracture toughness both decrease with increasing environmental temperature. It is also found that the fracture toughness without consideration of residual Stress is significantly larger than the intrinsic fracture toughness, which may result from the Compressive Stress State.

Zhengyi Jiang - One of the best experts on this subject based on the ideXlab platform.

  • a comparison of hot deformation behavior of high cr white cast iron and high cr white cast iron low carbon steel laminate
    Steel Research International, 2016
    Co-Authors: Jianzhong Xu, Zhengyi Jiang
    Abstract:

    In order to study the plastic deformation characteristics of the brittle high-Cr white cast iron in upsetting process, and find out the mechanism for improving the formability of the cast iron within the laminated composite, the hot forging process of monolithic high-Cr white cast iron and high-Cr white cast iron/low carbon steel laminate is simulated by means of hot compression tests using Gleeble 3500 thermo mechanical simulator and professional plastic forming software DEFORM-3D. The results reveal that during hot compression process, the monolithic cast iron suffered severe barreling and cracking, whereas the cast iron layer within the laminate underwent large plastic deformation with barreling-free and crack-free. Such a significant improvement can be attributed to the simultaneous deformation of the cast iron together with the low carbon steel claddings, which is beneficial to relieving the Stress in the cast iron and changing its deformation mode. Under the triaxial Compressive Stress State, the brittle high-Cr white cast iron within the laminate can flow like a ductile material at high temperatures and low strain rates.

S Zhu - One of the best experts on this subject based on the ideXlab platform.

  • a new hybrid identification method for determining the material parameters of thin walled tube under Compressive Stress State
    Materials & Design, 2013
    Co-Authors: Junting Liu, H Yang, S Zhu
    Abstract:

    Abstract Accurate and fast determination of material parameters of thin-walled tube under Compressive Stress State is essential for analyzing the Compressive-type tube forming process. For the thin-walled tube with hollow structure, it is difficult to determine the material parameters directly from the experiment since buckling occurs easily when the tube suffers axial Compressive loading. To accurately and rapidly identify the material parameters of thin-walled tube under Compressive Stress State, a hybrid inverse identification method is proposed based on tube lateral compression test with combining finite element simulation, regression analysis and genetic algorithm. By employing the proposed method, the Swift law hardening parameters of thin-walled tubes with different materials and specifications under Compressive Stress State are identified. Furthermore, the efficiency and accuracy of the proposed method are discussed in comparison with the previous researches. The results show that: (1) for 6061-T4 and 1Cr18Ni9Ti tubes, the maximum relative predicting errors of forces in tube lateral compression using the identified material parameters are less than 9%; (2) for aluminum tube ∅100 × 2 (diameter × thickness, mm), the maximum discrepancies between the simulated and experimental circumferential strains are less than 0.0274 for 30–70% reductions, and the simulated tube profiles deviate from the experiment less than 10% at reductions of 0–78%; and (3) the proposed method almost saves 80% computational time compared with the previous stepwise optimization method.

Junting Liu - One of the best experts on this subject based on the ideXlab platform.

  • a new hybrid identification method for determining the material parameters of thin walled tube under Compressive Stress State
    Materials & Design, 2013
    Co-Authors: Junting Liu, H Yang, S Zhu
    Abstract:

    Abstract Accurate and fast determination of material parameters of thin-walled tube under Compressive Stress State is essential for analyzing the Compressive-type tube forming process. For the thin-walled tube with hollow structure, it is difficult to determine the material parameters directly from the experiment since buckling occurs easily when the tube suffers axial Compressive loading. To accurately and rapidly identify the material parameters of thin-walled tube under Compressive Stress State, a hybrid inverse identification method is proposed based on tube lateral compression test with combining finite element simulation, regression analysis and genetic algorithm. By employing the proposed method, the Swift law hardening parameters of thin-walled tubes with different materials and specifications under Compressive Stress State are identified. Furthermore, the efficiency and accuracy of the proposed method are discussed in comparison with the previous researches. The results show that: (1) for 6061-T4 and 1Cr18Ni9Ti tubes, the maximum relative predicting errors of forces in tube lateral compression using the identified material parameters are less than 9%; (2) for aluminum tube ∅100 × 2 (diameter × thickness, mm), the maximum discrepancies between the simulated and experimental circumferential strains are less than 0.0274 for 30–70% reductions, and the simulated tube profiles deviate from the experiment less than 10% at reductions of 0–78%; and (3) the proposed method almost saves 80% computational time compared with the previous stepwise optimization method.

Rene Tinawi - One of the best experts on this subject based on the ideXlab platform.

  • finite element analysis of concrete swelling due to alkali aggregate reactions in dams
    Computers & Structures, 1996
    Co-Authors: Pierre Leger, P Cote, Rene Tinawi
    Abstract:

    Many concrete dams throughout the world are suffering from deteriorations induced by alkali-aggregate reaction (AAR) that impair the durability, serviceability, and might also affect, in the long term, the safety of the installation. AAR produces concrete expansion, and generally leads to a loss of strength, stiffness (cracking), and generates undesirable deformations and disturbances in the equilibrium of internal forces. This paper first presents a brief review of the physical processes that control the structural behaviour of concrete dams suffering from AAR. A methodology to distribute the observed concrete expansion in proportion to the Compressive Stress State, temperature, moisture, and reactivity of the constituents is then proposed for the numerical modelling of AAR concrete swelling in dams. A case study on a concrete spillway pier that is affected by AAR is presented to illustrate some features of the proposed methodology.