The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the fin...The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.展开更多
Ceramic matrix composite(CMC) and superalloy bolted joints have exhibited great potential for high temperature hot structure application in hypersonic aircraft. In service conditions, the thermal expansion mismatch be...Ceramic matrix composite(CMC) and superalloy bolted joints have exhibited great potential for high temperature hot structure application in hypersonic aircraft. In service conditions, the thermal expansion mismatch between CMC and superalloy plates will cause complex thermal stress and strain distributions at hole-edge areas and assembly parameters changes of the joints under elevated temperatures. These effects might lead to early damage of joint structure, which will endanger the structural integrity and load carrying capacity of aircraft components. In the present study, transient heat transfer and thermo-structural analysis of C/SiC composite and superalloy bolted joint were carried out by using a commercial FEA software ABAQUS. The stress distributions at hole-edge areas, pre-load loosening, and variation of bolt-hole clearance of CMC bolted joints under transient temperature rises were discussed for better understanding of high temperature structural behaviors. Results showed that pre-load declined with the increase of imposed hot side temperature, due to the thermal expansion mismatch between CMC and superalloy. The bolt-hole clearance for the composite plate decreased, whereas the clearance for the superalloy plate increased with the rise of temperature.展开更多
For a rotating machine with one or more tilting pad journal bearings (TPJBs), it is acommon state that pad-to-journal assembling clearances are uneven in one bearing, or inconsis-tent relationship of assembling cleara...For a rotating machine with one or more tilting pad journal bearings (TPJBs), it is acommon state that pad-to-journal assembling clearances are uneven in one bearing, or inconsis-tent relationship of assembling clearances are encountered among all the bearings. Consideringthe structural characteristics of a TPJB, a concept named as "pad pair pre-load coefficient" corre-sponding to bearing pre-load coefficient is proposed. Firstly, the influence of bearing pre-load coef-ficient and pad pair pre-load coefficient on shaft vibration in a Jeffcot rotor is analyzed. Then takingNo.1 unit with two TPJBs in Guangzhou pumped storage power plant (GPSP) as an example, theinfluence of inconsistent relationship of the two bearing pre-load coefficients on shaft vibration isanalyzed. The results show that variety of one bearing pre-load coefficient will only influence vibra-tion amplitude, not involving the shape of shaft center orbit. But variety of one or more "pad pairpre-load coefficient" will influence not only vibration amplitude, but also the shape of orbit-whichwill be turned from a circle to an ellipse. By investigating variation characteristics of shape andvibration amplitude of orbits at the TPJBs, some theoretical bases will be supplied for diagnosingthe condition of the unit bearings.展开更多
文摘The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.
基金Sponsored by the Pre-research Foundation of Shenyang Aircraft Design and Research Institute,Aviation Industry Corporation of China(Grant No.JH20128255)。
文摘Ceramic matrix composite(CMC) and superalloy bolted joints have exhibited great potential for high temperature hot structure application in hypersonic aircraft. In service conditions, the thermal expansion mismatch between CMC and superalloy plates will cause complex thermal stress and strain distributions at hole-edge areas and assembly parameters changes of the joints under elevated temperatures. These effects might lead to early damage of joint structure, which will endanger the structural integrity and load carrying capacity of aircraft components. In the present study, transient heat transfer and thermo-structural analysis of C/SiC composite and superalloy bolted joint were carried out by using a commercial FEA software ABAQUS. The stress distributions at hole-edge areas, pre-load loosening, and variation of bolt-hole clearance of CMC bolted joints under transient temperature rises were discussed for better understanding of high temperature structural behaviors. Results showed that pre-load declined with the increase of imposed hot side temperature, due to the thermal expansion mismatch between CMC and superalloy. The bolt-hole clearance for the composite plate decreased, whereas the clearance for the superalloy plate increased with the rise of temperature.
文摘For a rotating machine with one or more tilting pad journal bearings (TPJBs), it is acommon state that pad-to-journal assembling clearances are uneven in one bearing, or inconsis-tent relationship of assembling clearances are encountered among all the bearings. Consideringthe structural characteristics of a TPJB, a concept named as "pad pair pre-load coefficient" corre-sponding to bearing pre-load coefficient is proposed. Firstly, the influence of bearing pre-load coef-ficient and pad pair pre-load coefficient on shaft vibration in a Jeffcot rotor is analyzed. Then takingNo.1 unit with two TPJBs in Guangzhou pumped storage power plant (GPSP) as an example, theinfluence of inconsistent relationship of the two bearing pre-load coefficients on shaft vibration isanalyzed. The results show that variety of one bearing pre-load coefficient will only influence vibra-tion amplitude, not involving the shape of shaft center orbit. But variety of one or more "pad pairpre-load coefficient" will influence not only vibration amplitude, but also the shape of orbit-whichwill be turned from a circle to an ellipse. By investigating variation characteristics of shape andvibration amplitude of orbits at the TPJBs, some theoretical bases will be supplied for diagnosingthe condition of the unit bearings.
