Conceptual design of creep testing rig for full-scale cross arm using TRIZ-Morphological chart-analytic network process technique

Abstract

Cross arm is the main component used to lift the electric cable in a transmission tower. Recently, a synthetic cross arm was proposed to substitute the wooden cross arm due to the extreme creep deformation, which can induce a structural collapse. Several creep studies were conducted on a coupon scale for the synthetic cross arm. However, there is a lack of study on the assessment of creep properties for the actual size cross arm. Thus, the development of a special rig is required to accommodate the creep test. The paper explains the development of creep testing rig for a full-scale cross arm using the integration of theory of inventive problem solving (TRIZ), morphological chart, and analytic network process (ANP). In the beginning, the finding of principle solutions was conducted using the TRIZ contradiction matrix. The characterisation of the design concepts was elaborated using the morphological chart. Finally, the ANP principle was exploited to select the best design via the pairwise comparison technique. The results show that Concept Design 5 (hybrid bracing design) scored the highest value and ranked first. Lastly, challenges on the design of creep testing machine and the improving criteria in concurrent engineering is presented.