公开(公告)号：US20230289496A1

公开(公告)日：2023-09-14

申请号：US18097912

申请日：2023-01-17

Applicant: Tianjin University

Inventor： Lei ZHAO ,  Lianyong XU ,  Kai SONG ,  Yongdian HAN

IPC: G06F30/23

CPC classification number: G06F30/23 ,  G06F2119/02

Abstract: A method of predicting low-cycle fatigue crack initiation and propagation behaviors under a multi-scale framework includes the following steps: S1, providing a calculation method for low-cycle fatigue crack initiation and propagation damages under a multi-scale framework; S2, determining a slip system where a maximum damage is located and an accumulated damage of all slip systems by calculation using the calculation method in S1; S3, a crack initiating and propagating in a direction towards the slip system where the maximum damage is located when the accumulated damage reaches a critical value; and S4, conducting calculation repeatedly until a predicted crack length reaches a fracture length of a low-cycle fatigue specimen under test conditions.

公开(公告)号：US20230228728A1

公开(公告)日：2023-07-20

申请号：US17954682

申请日：2022-09-28

Applicant: Tianjin University

Inventor： Yongdian HAN ,  Shifang ZHONG ,  Lianyong XU ,  Hongyang JING ,  Lei ZHAO ,  Kangda HAO

IPC: G01N33/207 ,  G01N30/62 ,  G01N33/2045 ,  B23K31/12

CPC classification number: G01N33/207 ,  G01N30/62 ,  G01N33/2045 ,  B23K31/125 ,  G01N2030/027

Abstract: The present invention discloses a quantitative evaluation method for sensitivity of welding transverse cold cracks in a typical joint of a jacket, including following steps: S1, performing macroscopic analysis, metallographic analysis, fracture analysis and hardness analysis on cracks of a failed component to obtain main causes of cold crack failure; and S2, designing and processing a dedicated sample, and performing rigid restraint crack tests on the dedicated sample at different preheating temperatures to obtain a cracking/non-cracking critical restraint stress σ1cr of the sample. According to the method, a rigid restraint crack test is applied to evaluation of sensitivity of welding transverse cracks, so that external restraint conditions borne by a welding joint can be accurately simulated, a stress state of the welding joint in an actual working condition can be truly reflected, the overall evaluation precision is greatly improved, and a foundation is laid for accurately evaluating sensitivity of welding cold cracks in a tube joint. Furthermore, a welding technology (base material, welding material, welding process and restraint level) is designed to restrain cold cracks from cracking, and the method has important theoretical significance and engineering value.

公开(公告)号：US20240383076A1

公开(公告)日：2024-11-21

申请号：US18199371

申请日：2023-05-19

Applicant: Tianjin University

Inventor： Yongdian HAN ,  Jiyuan FEI ,  Lianyong XU ,  Lei ZHAO ,  Kangda HAO ,  Hongyang JIN

IPC: B23K31/12 ,  G01N3/08 ,  G01N33/207

Abstract: A method for determining the filling welding parameters of large deformation pipeline steel based on secondary regulation method includes: welding specimens to be welded for secondary welding thermal simulation experiments based on a thermal simulation to obtain samples after thermal simulation; processing the samples after thermal simulation into CTOD samples and calculating fracture toughness parameters; pre-loading of specimens requiring pre-strain after thermal simulation by uniaxial tension, and then processing samples before and after pre-strain after thermal simulation, conducting slow strain rate tension tests and calculating stress corrosion cracking susceptibility parameters; comparing the change in elongation of the samples before and after pre-strain and calculating the pre-strain sensitivity parameters; determining secondary thermal simulation parameters; converting the secondary thermal simulation parameters into welding heat input parameters; determining welding parameters based on welding heat input parameters; determining the optimal role of the welding parameters.

公开(公告)号：US20180272476A1

公开(公告)日：2018-09-27

申请号：US15762094

申请日：2016-09-23

Applicant: Tianjin University

Inventor： Lianyong XU ,  Yongdian HAN ,  Hongyang JING ,  Lel ZHAO ,  Xiaoqing LV

IPC: B23K35/26 ,  B22F9/04 ,  B22F1/00 ,  B23K35/40 ,  C22C13/00

CPC classification number: B23K35/262 ,  B22F1/0011 ,  B22F9/04 ,  B22F2009/043 ,  B22F2201/11 ,  B22F2201/20 ,  B22F2301/30 ,  B22F2304/10 ,  B22F2998/10 ,  B22F2999/00 ,  B23K35/0244 ,  B23K35/26 ,  B23K35/3601 ,  B23K35/40 ,  C22C13/00 ,  C22C47/14 ,  C22C49/02 ,  C22C49/14 ,  C22C1/05 ,  B22F3/02 ,  B22F3/10

Abstract: This invention discloses a method for preparing a kind of Sn-based silver-graphene lead-free composite solder, including mixing a certain amount of graphene with sodium dodecyl sulfate, then adding a certain amount of dimethylformamide, sonicating for 2 hours, adding a certain amount of silver nitrate to the mixture, continuing the sonication and finally obtaining the homemade. The solders matrix powder is weighed according to different silver-graphene mass fraction required, then poured into a ball-milling tank milling for 5 h. The powder is poured into a stainless steel mold after drying, then placed under hydraulic pressure to 500 Mpa for pressure forming. Later, the cold-pressed cylinder is placed in a high vacuum tube resistance furnace and sintered at 175° C. for 2 hours. After cooling to room temperature, it is formed into a cylinder under the hydraulic press. In this invention, graphene modified with Ag particles is selected as a strengthening material so as to improve the load-transfer between the graphene modified by nano-silver and the Sn matrix, aiming to achieve better strengthening effect.

公开(公告)号：US20240012958A1

公开(公告)日：2024-01-11

申请号：US17979002

申请日：2022-11-02

Applicant: TIANJIN UNIVERSITY

Inventor： Lei ZHAO ,  Molin SU ,  Yongdian HAN ,  Lianyong XU ,  Kangda HAO

IPC: G06F30/20 ,  G01N33/2045

CPC classification number: G06F30/20 ,  G01N33/2045 ,  G06F2111/10

Abstract: A method for characterizing propagation of metallic short cracks and long cracks includes: acquiring crack tip opening displacement in a metallic notched sample under cyclic loading; acquiring crack tip opening displacement amount caused by a single monotonic tensile in the notched sample, and crack tip opening displacement caused by monotonic tensile in the notched sample under a maximum far-field stress; and based on an original Shyam model, constructing, according to the crack tip opening displacement amount and the crack tip opening displacement by obtaining yield strength of metals, a Tmφc model for characterizing the propagation of short cracks and long cracks, where the Tmφc model is used for representing the growth rate of short cracks and long cracks.

公开(公告)号：US20230324268A1

公开(公告)日：2023-10-12

申请号：US17716217

申请日：2022-04-08

Applicant: TIANJIN UNIVERSITY

Inventor： Lianyong XU ,  Lei Zhao ,  Yongdian Han ,  Chao Feng

IPC: G01N3/20 ,  B63B79/30

CPC classification number: G01N3/20 ,  B63B79/30 ,  G01N2203/0296 ,  G01N2203/0019 ,  G01N2203/0252 ,  G01N2203/0017 ,  G01N2203/0254

Abstract: Disclosed is a deepwater platform welded joint testing system. The testing system comprises a host unit, a hydraulic unit and a control unit, wherein the control unit is connected with the host unit and the hydraulic unit respectively; the host unit comprises a bearing frame placed on a bearing base, biaxial tension/compression loading oil cylinders mounted on the bearing frame, a lateral force resistant mechanism connected to the front ends of the biaxial tension/compression loading oil cylinders, counter-force supports fixed to the top end of the bearing frame and biaxial bending loading oil cylinders mounted on the counter-force supports. According to the deepwater platform welded joint testing system, through the independent or synergistic effect of the six loading oil cylinders, stretching and fatigue performance tests of a large complex structure under uniaxial tension/compression, uniaxial bending, biaxial tension/compression, biaxial bending and uniaxial/biaxial tension/compression and bending composite loads can be achieved.