Analytical approach to robust design of nonlinear mechanical systems

Abstract

The robustness of mechanical systems is influenced by various factors. Their effects must be understood for designing robust systems. This paper proposes a model for describing the relationships among functional requirements, structural characteristics, design parameters and uncontrollable variables of nonlinear systems. With this model, the sensitivity of systems was analyzed to formulate a system sensitivity index and robust sensitivity matrix to determine the importance of the factors in relation to the robustness of systems. Based on the robust design principle, an optimization model was developed. Combining this optimization model and the Taguchi method for robust design, an analysis was carried out to reveal the characteristics of the systems. For a nonlinear mechanical system, relationships among structural characteristics of the system, design parameters, and uncontrollable variables can be formulated as a mathematical function. The characteristics of the system determine how design parameters affect the functional requirements of the system. Consequently, they affect the distribution of system performance functions. Nonlinearity of the system can facilitate the selection of design parameters to achieve the required functional requirements.

Modelling and experimental research in hot precision forging of shaft gear

“…The friction conditions prevailing at the interface of die-workpiece was 0.3 at the hot forging condition. The value of heat transfer coefficient between workpiece and dies used in literature, 5/N/Sec/mm/°C [7].…”

Investigation on a New Type of Pneumatic Flexible Joint

“…In China, Zhejiang University of Technology put forward a type of flexible cylinder. This flexible cylinder is mainly composed of rubber tube, end cap and spiral steel wires, and the spiral steel wires embed in the rubber tube [5]. In addition, some researchers of Beihua University developed a new type bidirectional controllable flexible bending joint based on elongation artificial muscles, and which can axial elongate and bend two-dimensional two-way control in space [6].…”

Analysis on Ground Surface Damage of Quartz Fiber-Reinforced Quartz Composites

“…Fiber-reinforced composites which is easy to produce matrix cracking, degumming, delamination, fiber breakage and other damages in the machining process , is difficult to machine [2]. Currently， domestic and foreign scholars have conducted a series of studies about fiber-reinforced composites machining [2][3][4][5][6][7]. M RAMULU who is from University of Washington has studied machining and surface integrity of fiber-reinforced plastic composites, and confirmed that manufacturing characteristics may not only bulk properties but also influence the initiation and propagation of failure [3]; Osaka University scholars believe that because the shear stress which is perpendicular to the axis of the fiber itself exceeds the ultimate shear strength，carbon fiber was cut off [2]； Y.M.Quan et al who are from South China University of Technology have researched the composites cutting surface structure, proposed that damage of fiber-reinforced composites is significantly dependent on the angle between the fiber arrangement and the cutting orientation [4].…”