Hanying Mao

Semantic hyper-graph-based knowledge representation architecture for complex product development

Abstract More and more manufacturing companies are facing challenges in knowledge refining and reusing in stage of product development. To resolve this problem and make the knowledge convenient for acquisition, machine-understandable and human-understandable, this paper proposes a framework of semantic hyper-graph-based knowledge representation to support the knowledge sharing for the product development. A case study of car headlamp development is given to validate the feasibility and effectiveness of the proposed method. The results bring out that it can help engineers to rapidly and accurately acquire knowledge. In future research, the knowledge recommendation service based on product development process should be considered.

Product lifecycle–oriented knowledge services: Status review, framework, and technology trends

More companies are facing challenges in extracting and utilizing knowledge in product lifecycle. To solve this problem, a product lifecycle–oriented knowledge service framework is proposed based on the status review. The proposed framework is supported by four key methods and processes, which include mechanism of knowledge service identification, mechanism of product knowledge service transfer, delivery process of product knowledge service, and performance evaluation of product knowledge service. Different with most of the previous fragmental studies, the proposed systematic knowledge service framework is mainly product lifecycle oriented. In addition, an application in gantry crane design shows that the proposed framework can provide effective lifecycle knowledge support for product development, which will help to promote concurrency and simultaneity in product development process.

Feasibility of Residual Stress Nondestructive Estimation Using the Nonlinear Property of Critical Refraction Longitudinal Wave

Residual stress has significant influence on the performance of mechanical components, and the nondestructive estimation of residual stress is always a difficult problem. This study applies the relative nonlinear coefficient of critical refraction longitudinal ( ) wave to nondestructively characterize the stress state of materials; the feasibility of residual stress estimation using the nonlinear property of wave is verified. The nonlinear ultrasonic measurements based on wave are conducted on components with known stress state to calculate the relative nonlinear coefficient. Experimental results indicate that the relative nonlinear coefficient monotonically increases with prestress and the increment of relative nonlinear coefficient is about 80%, while the wave velocity only decreases about 0.2%. The sensitivity of the relative nonlinear coefficient for stress is much higher than wave velocity. Furthermore, the dependence between the relative nonlinear coefficient and deformation state of components is found. The stress detection resolution based on the nonlinear property of wave is 10 MPa, which has higher resolution than wave velocity. These results demonstrate that the nonlinear property of wave is more suitable for stress characterization than wave velocity, and this quantitative information could be used for residual stress estimation.

Chaotic characteristics analysis of simulation signal of ultrasonic nonlinear modulation effect

The effectiveness of chaos and fractal theory in analyzing ultrasonic nonlinear modulation signal was theoretically verified and a new way of using chaos and fractal theory in nondestructive testing is provided based on the simulation signal of ultrasonic nonlinear modulation effect. By constructing the simulation signal of modulation effect, the simulation signal with the chaotic character was found, and the nonlinear parameter and characteristic values of chaos theory were calculated to analyze the nonlinearity of specimens. By comparisons, the conclusion could be found that the Lyapunov exponent was sensitive to weaker nonlinearity and unsusceptible to noise.