## 2 Components and Methods  
### Structure and Parameters of Components  
A suspension rod assembly for suspension of fixed cold mass was designed and manufactured for a custom monocrystalline silicon superconducting magnet with a hole diameter of 1600 mm at room temperature. According to theoretical calculation, the maximum axial tensile load of each group of tie rods is about 84 kN (Table 1). If the safety factor S = 1.7 is set according to engineering experience, the rated axial tensile load of the used tie rods should exceed 142.8 kN. There are three types of tie rod designs that meet the load and length requirements (Figure 1), in which type A and type B are racetrack-shaped designs, and the rod body is wound by parallel T300 long carbon fibers. The arc section diameter of the type A tie rod is larger, and the two ends of the rod body are equipped with metal washers and joint bearings, which make the swing more flexible while occupying more space inside the magnet. The type B tie rod group is compact in structure, but the flexibility is slightly worse. The rod body of the type C tie rod is made of whole CFRP rod material, applying a T300 long carbon fiber parallel arrangement, both ends are connected by epoxy resin adhesive and tension bolt, which is more compact than the type A and B structure. The material parameters involved in the simulation calculation are as close as possible to the materials used in the experiment. In addition, the materials used in the tie rod group include American standard ISI304 stainless steel and T300 carbon fiber in CFRP. \begin{table}
\begin{tabular}{c c c c} \hline
**Type of Load** & **Pull Rod Axial Load** & **Excitation Stage** & **Transport Stage** \\ \hline Cold mass gravity & 6.63 kN & \(\surd\) & \(\surd\) \\ Shrinkage elastic force & 5.5 kN & \(\surd\) & / \\ Bolt pre-tightening force & 27 kN & \(\surd\) & \(\surd\) \\ Electromagnetic & 45 kN & \(\surd\) & / \\ component & 18 kN & / & \(\surd\) \\ Transport shock & 18 kN & / & \(\surd\) \\ Total & / & 84.13 kN & 51.63 kN \\ \hline \end{tabular}
\end{table} 
Table 1: Tensile load of MCZ magnet cold mass on tie rod group. Figure 1: Existing mature draw-rod structure schemes for the manufacture of superconducting magnets. In order to solve the problems of high processing cost, long cycles and unstable quality, this study designed the type D adjustable tie rod (Figure 2) and successfully applied it to the assembly and manufacturing of magnets. The core of the design of the adjustable tie rod structure is the special clamping device at both ends of the CFRP rod body and the standardized CFRP branch rod. As shown in Figure 3, the clamping device at both ends of the CFRP rod body consists of a chuck made of 304 material and a conical sleeve. The shape of the chuck matches the taper of the sleeve, which creates a self-locking effect through the conical structure, ensuring a firm clamping of the CFRP rod body. When the chuck is pressed into the conical sleeve, the chuck is radially compressed due to the taper action, so as to tightly clamp the branch rod. The inside of the chuck distributes a plurality of through holes evenly along the circumference so as to hold a plurality of branches simultaneously. The outer surface of the sleeve is provided with a thread, and the end is provided with a square wrench clamp. The T300 filament tow carbon fiber used in the CFRP branch rods is supplied by Weihai Guangwei Carbon Fiber Co., LTD., and processed in batches by China National Carbon Corporation's plant. The carbon fiber is arranged in parallel along the axis to make a standardized slender rod with a diameter of 2 mm and a length of 1000 mm for subsequent use. Figure 3: Components included in the Type D adjustable tie rod. Figure 2: An adjustable pull rod for supporting the cold mass of magnet in MCZ. In the assembly stage, the branch rod is first cut to the appropriate length, and the defective individual is removed.