To obtain better fatigue resistance for marine engineering equipment welded joints in the design stage, the design method of the marine engineering equipment welded joint design…
Abstract
Purpose
To obtain better fatigue resistance for marine engineering equipment welded joints in the design stage, the design method of the marine engineering equipment welded joint design stage needs to be studied.
Design/methodology/approach
Based on the structural stress theory, a design method of the marine engineering equipment welded joints with better fatigue performance is proposed. The effectiveness of the method is demonstrated through the simulation analysis and fatigue test of typical marine engineering equipment welded joints.
Findings
Methods based on the theoretical advantages of structural stress and the principle of ensuring that the welded joint has a low degree of stress concentration.
Originality/value
The design method of marine engineering equipment welded joints proposed in this study provides a set of operable design routes for technicians, which can better meet the needs of engineering applications.
Details
Keywords
Chunliang Niu, Suming Xie and Tao Zhang
In order to obtain the relationship between the geometry and stress concentration of load-bearing welded joints, the fatigue design method of welded structures based on stiffness…
Abstract
Purpose
In order to obtain the relationship between the geometry and stress concentration of load-bearing welded joints, the fatigue design method of welded structures based on stiffness coordination strategy is studied.
Design/methodology/approach
Based on the structural stress theory, a new method for anti-fatigue design of welded structures oriented to stiffness coordination strategy is proposed, and the detailed implementation process of this method is given. This method is also called the three-stage anti-fatigue design method for welded structures, which includes three stages, namely, identification, analysis and relief of stress concentration.
Findings
Through the experimental analysis of welded joints in IIW standard, the effectiveness of stiffness coordination in welded joint design is proved. The method is applied to the design of welded parts and products, and the feasibility of the method in alleviating the phenomenon of stress concentration and improving the fatigue resistance of welded structures is verified.
Originality/value
In this study, based on the principle of coordinated design of weld stiffness, a three-stage anti-fatigue design method of welded structure is proposed. The method has practical value for the optimization design and anti-fatigue performance improvement of welded structure in engineering products.
Details
Keywords
Chunliang Niu, Chunfei Bai, Liming Guo, BingZhuo Liu and Lei Chen
In order to improve the rationality of the design of carbon fiber composite riveting structures in engineering products and reduce physical tests, the stress changes of various…
Abstract
Purpose
In order to improve the rationality of the design of carbon fiber composite riveting structures in engineering products and reduce physical tests, the stress changes of various parts during the carbon fiber-reinforced polymer (CFRP) riveting process, the influence area of hole edge stress and the damage of CFRP plates were studied from the perspective of numerical simulation. The reasonable arrangement requirements of composite riveted structures, installation speed and damage characteristics of CFRP plates in engineering applications are obtained. The research results provide technical references for the design and installation of composite riveting structures in engineering products.
Design/methodology/approach
Taking the forming process of the riveted structure between countersunk blind rivets and CFRP plates as the research object, the forming principle of countersunk blind rivets and the damage characteristics of CFRP plates were analyzed. Using contact nonlinearity theory, the anisotropic material modeling method and the Hashin failure criterion, the stress changes in various parts during the riveted joint forming process, the influence area of stress at the hole edge of the rivet holes and the damage of the CFRP plates were analyzed.
Findings
Reasonable rivet layout spacing was obtained; the peak stress of the rivet assembly increases with the increase of the rivet installation speed, and the influence area of the hole edge on the CFRP plate is a circular area with an outward extension radius of 0∼6 mm. Therefore, the arrangement distance between rivets is greater than the ring area, the damage law and installation speed of CFRP plates are given, the damage extends inward from the first layer of the laminates and the installation speed of 15 mm/s can satisfy the requirement of riveting installation better.
Originality/value
The riveting and forming process under different speeds is analyzed from the perspective of numerical simulation, and the stress variation rule of each part of the rivet and the damage of the CFRP plate under each speed are obtained. Reasonable rivet arrangement requirements and installation speed were given. This study provides technical support for the rivet arrangement method and mechanical property analysis of CFRP riveted structures in complex engineering products.
Details
Keywords
Chunliang Niu, BingZhuo Liu, Chunfei Bai, Liming Guo, Lei Chen and Jiwu Tang
In order to improve the efficiency and reliability of simulation analysis for composite riveting structures in engineering products, a comparative study was conducted on different…
Abstract
Purpose
In order to improve the efficiency and reliability of simulation analysis for composite riveting structures in engineering products, a comparative study was conducted on different forms of riveting simulation methods.
Design/methodology/approach
Five different rivent simulation models were established using the finite element method, including rigid element CE, flexible element Rbe3 and beam element, and their results were future compared and analyzed.
Findings
Under the given technical parameters, the simulation method of Rbe3 (with holes) + beam can meet the analysis requirements of complex engineering products in terms of the rationality of rivet load distribution, calculation error and relatively efficient modeling.
Originality/value
This study proposes a simulation method for the riveting structure of carbon fiber composite materials for engineering applications. This method can satisfy the simulation analysis requirements of transportation vehicles in terms of modeling time, computational efficiency and accuracy. The research can provide technical support for the riveting process and mechanical analysis between carbon fiber composite components in transportation products.
Details
Keywords
Chunliang Niu, Suming Xie, Xiangwei Li and Wen Wang
In order to use the BS EN 15058-3 principle more scientifically to design the welding structure of rail vehicles, a method of stress state assessment of welding joints meeting the…
Abstract
Purpose
In order to use the BS EN 15058-3 principle more scientifically to design the welding structure of rail vehicles, a method of stress state assessment of welding joints meeting the requirements of BS EN 15058-3 is proposed by using IIW-2008 and ASME-BPVC-VIII-2:2015 standard.
Design/methodology/approach
The stress state evaluation process of two standards is studied, and the stress state evaluation method of two standards is programmed by computer language. Among them, ASME standard can evaluate the stress state of welding structures without defects and with defects. In order to verify the feasibility of the method, under the fatigue load of en13749 standard, the method is applied to the welding structure design of the rail car frame.
Findings
The results show that the evaluation based on IIW-2008 standard is stricter, and the stress factor of the weld between the crossbeam and the traction pull rod seat is the largest, the value is 0.881, and the stress state grade is medium. With the increase of the number of defects, the stress level of the welded joint increases and the fatigue life decreases.
Originality/value
This study can provide a reference for the welding design of rail vehicles and other complex structures and has a certain engineering guiding significance.
Details
Keywords
Suming Xie, Chunyun Li, Jian Wang, Wanpeng Li and Chunliang Niu
Based on the DVS1608-2011 and IIW-2008 and BS EN15085-3 standards, the stress state grade of welded joints of aluminum alloy EMU (Electric Multiple Units) body was studied.
Abstract
Purpose
Based on the DVS1608-2011 and IIW-2008 and BS EN15085-3 standards, the stress state grade of welded joints of aluminum alloy EMU (Electric Multiple Units) body was studied.
Design/methodology/approach
First, the calculation methods of the stress state grade of aluminum alloy welded joints analyzed by DVS1608-2011 and IIW-2008 standards were studied, and the two methods were programmed by the APDL language of ANSYS. Then, the finite element model of aluminum alloy EMU body was established; the static strength calculation result of the body was compared with the test result, and the error is basically within 10%. Finally, under the acceleration fatigue load provided by BS EN12663 standard, the fatigue analysis was carried out on the welded joint of the vehicle body, and the stress state of the welded joint of the vehicle body was studied according to IIW-2008 and DVS1608 standards, respectively.
Findings
The results show that the assessment method based on IIW-2008 standard is more rigorous, and the maximum stress factor of the longitudinal weld between the side beam and the side wall is 0.811; the position occurs in the area where the longitudinal weld of the side beam and the side wall is close to the lower door angle.
Originality/value
The stress state is medium, and the rest of the weld stress states are low.
Details
Keywords
Yih-Lin Cheng, Chih-Hsuan Chang and Chunliang Kuo
The material-jetting-type (MJ) 3-D printing technology has advantages in resolution and color printing. During the printing process, a leveling technique is needed to precisely…
Abstract
Purpose
The material-jetting-type (MJ) 3-D printing technology has advantages in resolution and color printing. During the printing process, a leveling technique is needed to precisely control the thickness and flatness of each layer. Roller-type leveling mechanism has been adopted in commercial MJ 3-D printers, but it is lack of research on roller leveling process parameters and establishing experimental procedures. Therefore, in this study, a roller-type leveling mechanism for a MJ color 3 D printer was developed, and experimental approaches were utilized to determine process parameters.
Design/methodology/approach
The roller-type leveling mechanism was chosen to provide functions of flattening and removal of excess material. The parameters studied were roller speed and rotational direction. Surface roughness, Ra, of printed single-layered specimens was measured at 15 locations for plane roughness and along five lines for line roughness to evaluate the leveling results. Adopting suitable parameters, color samples with and without leveling were printed for comparison and verification.
Findings
According to plane roughness results, forward rotation achieved better leveling. Plane roughness was the major criteria to determine roller speed with the assistance of standard deviation of line roughness. The best parameters of the self-developed MJ color 3-D printer were found to be rolling forward at 1,100 rpm. In addition, printed color samples showed great improvement in surface roughness with leveling and no obvious color mixing after leveling.
Research limitations/implications
Leveling is important to achieve desired layer thickness, smooth surface and good color quality in color 3-D printing. For MJ 3-D printing, only patents were revealed regarding roller design, but paper publications have not been presented. This research practically proposed to use experimental approach to understand the effects of roller operating parameters and to find the suitable ones based on surface roughness results.
Practical implications
This research established the experimental procedures and also suggested guidelines of experimentally obtaining suitable roller leveling process parameters. Developers can refer to this study results to design and adjust leveling mechanism in a new MJ 3-D printer.
Originality/value
The experimental approach can be applied to similar MJ 3-D printing systems if different materials are introduced or the platform speed is changed. The observed trends suggested several guidelines to plan limited experiments only to obtain suitable roller process parameters.