Huang Xinyue, Wu Xueren, Markus Lang. A Measurement Method for Crack Growth Driving Force and Crack Closure[J]. Journal of Materials Engineering, 1997, 0(6): 3-5.
A measurement method is described in this paper for crack growth driving force Kpr. This method is based on the crack threshold behavior and implemented with direct potential drop method. According to this method the crack driving force can be obtained and the effective stress intensity factor range can be determined by △Keff=Kmax-Kpr.
Liu Shaolun, Tu Bolin, Cui Shangxiang. Study on Test Methods for Bending Strength and Fracture Toughness of CMC at 1000~1350℃[J]. Journal of Materials Engineering, 1997, 0(6): 6-8.
This paper presented how to use and improve the old material for establishing test methods testing machine for bending strength and fracture toughness of CMC at 1000~1350℃.Comparison of test results and data with that from different literatures sources indicated that the test for bending strength and fracture toughness CMC of 1000~1350℃ are reliable and reasonable. However effect of specimen geometry and size on mechanical properties of CMC is future research.
Liu Qingquan. Fracture Analysis for Rotor Blade Tenon of an Aeroengine Compressor[J]. Journal of Materials Engineering, 1997, 0(6): 9-11.
Fracture of 4th rotor blade tenon No 35 of an aeroengine compressor has been analyzed using SEM and simulation test. The results shown that the blade is fatigue fracture caused by fretting between the tenon and tenon gear and the fretting is led by local large contact stress because of interference fit in machining. An improved measures has been proposed to prevent similar accidents.
Li He, Li Renzeng, Wang Fengxiang, Yan Chaohua. An Investigation on the Fracture Mechanics Behavior of New High Temperature Material Using Moire' Interometry[J]. Journal of Materials Engineering, 1997, 0(6): 12-14,45.
This paper briefly introduces high temperature moire interferometry technique which is used for investigating the fracture mechanics behavior of new materials theoretic basis of high-temperature fracture mechanics and image pattern process. Finally by way of comparison analysis and application of domestic with foreign research this paper expounds the significance of moire' interferometry used for fracture mechanics fo the new materials.
Zhou Shaorong, Qiao Shengru, Bai Shihong, Sun Xiaoyan. The Study of Mechanical Property of Unidirectional C/C Composites Fabricated with Mesophase Pitch in a Magnetic Field[J]. Journal of Materials Engineering, 1997, 0(6): 15-16,33.
It is found that the interface of unidirectional C/C composits fabricated with mesophase pitch in an 0.8T magnetic field belongs to TOG (Transversely Oritented Graphite) a kind of the weak interface of the composites and the flexural strength of this kind of composite decreases slightly. In addition its ductility increases strongly. The work here is an effort to investigate the influence of TOG on the mechanical property of the composites.
Zhang Xingan. The Relation of Material Hardening Exponent and Shape Parameters of Stress-strain Curve[J]. Journal of Materials Engineering, 1997, 0(6): 17-19.
Based on the measurement of stress-strain curves at high temperature the relation between material hardness from data manual and the shape parameter used in stability evaluation was investigated. The relation was supported by the test data. The results show that a reciprocal relation exist in the hardening exponent and curvature shape parameter. But it is not very exact in engineering application.
Li Guansheng, Li Jianyou, Xu Xin. The Tensile Performance Test Study of Three-Dimensional Braided Composites[J]. Journal of Materials Engineering, 1997, 0(6): 20-21,41.
The test method of 3DBC tensile performance based on GB1446 GB3354-82 and the study of the microstructure of 3DEC has been discussed in this paper. Furthermore,the relationship between the braid parameters and 3DBC tensile performance has been summarized through the test data.
Guo Hongquan, Xu Ruixian, Shen Yue. DFRcutoff Values of LY12CZ,LC4CS Aluminum Alloys and 30CrMnSiA Steel in Several Environments[J]. Journal of Materials Engineering, 1997, 0(6): 22-23,27.
The experimental studies of "detail fatigue ratings cutoff (DFRcutoff)" of LY12CZ,LC4CS aluminum alloy and 30CrMnSiA steel commonly used in aircraft structures were conducted in different environment and aircraft structure durability design were provided with important experimental data. The program demonstrated that the effects of different environment oh material life are different laboratory air moist air and 3.5% NaCl solution are listed in order of increasing potency.
Ning Yongzhao. A Test Research of GC11 Steel Sheet[J]. Journal of Materials Engineering, 1997, 0(6): 24-27.
The welded specimens of GC11 steel sheet was investigated for its properties on axiale tension notch fatigue lower temperature tension lower temperature impact toughness and bending. A comparison was made with 30CrMnSiA steel sheet. The tendency of lower temperature brittle was evaluated by impact test and explosion test. The results are useful to choose proper materials in engineering.
Ma Shusheng. Fracture Mechanics Test on High Speed Wind Tunnel Resource Air Vessel Material and the Application of Safety Evaluations[J]. Journal of Materials Engineering, 1997, 0(6): 28-30,19.
Defect on air pressure vessel materials of high speed wind tunnel resource was inspected by means of ultrasonic radiographic and magnetic particle. Fatigue crack threshold and fatigue crack propagation rate for matrix and weld were calculated using COD finite element and stress intensity factor. Finally on the basis of these results the engineering safety for the air pressure vessel material was evaluated. It was found that the air pressure vessel can be safely operated when maximum operating pressure P=0.686MPa and cycle pressure range △P= 0.392MPa and can be further used for 14 years if operated at 300 cycle/year.
Meng Huafang. Comparing Proof Stress of Non-proportional Elongation by Two Diagram Methods[J]. Journal of Materials Engineering, 1997, 0(6): 31-33.
Tensile test system was analyzed by two different modulus of elasticity. Two kinds of diagram methods were applied to obtain the proof stress of non-proportional elongation. The precisions of two methods based on extensometer and cross-head displacement were discussed. The disadvantige of cross-head displacement method was pointed out and improvement of strain gauge method was discussed.
Jin Lei, Xia Huiqin. Exploring Research on Torsional Fatigue Properties in Stainless Steel, Aluminum Alloy and Structural Steel[J]. Journal of Materials Engineering, 1997, 0(6): 34-35,5.
Exporing research on torsional fatigue test method and the torsional fatigue tests in stainless steel aluminum alloy and structural steel were conducted on MTS 809 torsional test machine the results showed that torsional fatigue life of these serveral metals depends on those difference between axial strain and shear strain.
He Zhuli. The Low Cycle Fatigue Behavior of Engine Turbine Disk[J]. Journal of Materials Engineering, 1997, 0(6): 36-38.
The engine turbine disk material GH33A was tested for low cycle fatigue behavior before stress ageing and after 3000 hours stress ageing respectively. The cyclic hardening characterization were analyzed by the recorded cyclic and monotone stress-strain curve. With strain-life relation data static and low cycle fatigue parameters of GH33A were generated for application to the design materials selecting and life estimation.
Qin Fang. The Effect of Several Factors on the Microhardness Test Value[J]. Journal of Materials Engineering, 1997, 0(6): 39-41.
The effect of load specimen surface roughness and test deviation amendment on microhardness of aeronautical noble metal (alloy) wires and sheets was studied in this paper. It was found that the measurement results are very exact in case of diagonal of indentation not less than 40μm and roughness of surface not more than 0.125μm.
Wang Baohua. KR Curve Test of Al-Ti Bimetal Sheet[J]. Journal of Materials Engineering, 1997, 0(6): 42-42,38.
Two series of Al-Ti metals sheets from discard airplane parts and self made material were tested on normal mechanics and fracture mechanics. The KR curves were obtained according to test standard. By flexibility and K calculations KRi and aiwere measured separately and Kc was determined. Comparing the data of two series sheets the performances are very similar the new sheet was qualified to meet the property requirements of imported sheet.
Nan Junma, Li Guangxin, Sun Hailin, Xu Kewei, Wang Hongxing, Dou Xiuying, Song Lijian. A Strain-gauge Method for Determining Yield Strength of Materials[J]. Journal of Materials Engineering, 1997, 0(6): 43-45.
This paper explored the possibility of measuring yield strength with strain gauges. The proper strain gauges were selected for measurement of strain to be made in the elastoplastic region and the comparison tests were carried out of both strain gauge and extensometer for each specimen so that the yield strength measured may be examined to be identical or not. Determinations exhibit that the maximum difference of the measured values is 7MPa for the same specimen and the difference of average values is less than 7 MPa for the different specimens with the same processing state. Such an error is negligible so the strain gauge method is available for measurement of yield strength in actual practice and is proved to possess the same measuring accuracy with the extensometre.
