In the field of mechanical equipment manufacturing, the focus of research and development is not on weight reduction, but on how to choose between the rigidity and performance of components (such as strength or flexibility). For this contradiction, lightweight is one of the best solutions. The problems associated with lightweight were initially considered and systematically studied in aircraft manufacturing in engineering. Therefore, lightweight has been greatly developed in aviation research and has played an increasingly important role in construction machinery. This paper presents a brief description of the current status of lightweight in machinery by reviewing some significant progress made in the last decades. Potential research topics are also discussed from the four aspects of material, structure, bionics, and manufacturing, and they forecast the development trend of lightweight in the future construction machinery. The entire body of literature about the field is not covered due to the limitation of the length of paper. The scope of this review is limited and closely related to the development of lightweight technology in engineering applications.

Based on the perspective of cost risk management of the entire process of power grid construction project, the WBS-RBS risk identification method is applied. The risk factors of power grid engineering cost are comprehensively identified from the five major engineering cost formation stages: investment decision estimate stage, design estimate stage, bidding price stage, construction budget stage, and final account stage. Combined with the basic data obtained from the questionnaire, the membership degree method is adopted to screen the key indicators of the preliminary factors of cost risk and then eliminate the redundant indicators. Furthermore, a set of simple and efficient risk evaluation index system for power grid engineering cost is constructed in order to improve the risk evaluation and management level of power grid construction project in China.