Throughout the vehicle crash event, the interactions between vehicle, occupant, restraint system (VOR) are complicated and highly non-linear. CAE and physical tests are the most widely used in vehicle passive safety d...Throughout the vehicle crash event, the interactions between vehicle, occupant, restraint system (VOR) are complicated and highly non-linear. CAE and physical tests are the most widely used in vehicle passive safety development, but they can only be done with the detailed 3D model or physical samples. Often some design errors and imperfections are difficult to correct at that time, and a large amount of time will be needed. A restraint system concept design approach which based on single-degree-of-freedom occupant-vehicle model (SDOF) is proposed in this paper. The interactions between the restraint system parameters and the occupant responses in a crash are studied from the view of mechanics and energy. The discrete input and the iterative algorithm method are applied to the SDOF model to get the occupant responses quickly for arbitrary excitations (impact pulse) by MATLAB. By studying the relationships between the ridedown efficiency, the restraint stiffness, and the occupant response, the design principle of the restraint stiffness aiming to reduce occupant injury level during conceptual design is represented. Higher ridedown efficiency means more occupant energy absorbed by the vehicle, but the research result shows that higher ridedown efficiency does not mean lower occupant injury level. A proper restraint system design principle depends on two aspects. On one hand,the restraint system should lead to as high ridedown efficiency as possible, and at the same time, the restraint system should maximize use of the survival space to reduce the occupant deceleration level. As an example, an optimization of a passenger vehicle restraint system is designed by the concept design method above, and the final results are validated by MADYMO, which is the most widely used software in restraint system design, and the sled test. Consequently, a guideline and method for the occupant restraint system concept design is established in this paper.展开更多
Objective: Physical restraint is frequently used in medical services,such as in mental health settings,intensive care units and nursing homes,but its nature varies in different institutions.By reviewing related litera...Objective: Physical restraint is frequently used in medical services,such as in mental health settings,intensive care units and nursing homes,but its nature varies in different institutions.By reviewing related literature,this study aims to clarify the concept of physical restraint in mental health nursing.Method: Three databases (PubMed,PsyclNFO and CINAHL) were retrieved,and Walker and Avant's concept analysis method was used to analyze the concept of physical restraint in mental health nursing.Results: Physical restraint is a coercive approach that enables the administration of necessary treatment by safely reducing the patient's physical movement.It should be the last option used by qualified personnel.Antecedents of physical restraint are improper behavior (violence and disturbance) of patients,medical assessment prior to implementation and legislation governing clinical usage.Consequences of physical restraint are alleviation of conflict,physical injury,mental trauma and invisible impact on the institution.Discussion: This study defined the characteristics of physical restraint in mental health nursing.The proposed concept analysis provided theoretical foundation for future studies.展开更多
The current design and optimization of the occupant restraint system（ORS） are based on numerous actual tests and mathematic simulations. These two methods are overly time-consuming and complex for the concept design...The current design and optimization of the occupant restraint system（ORS） are based on numerous actual tests and mathematic simulations. These two methods are overly time-consuming and complex for the concept design phase of the ORS, though they＇re quite effective and accurate. Therefore, a fast and directive method of the design and optimization is needed in the concept design phase of the ORS. Since the airbag system is a crucial part of the ORS, in this paper, a theoretical model for the vehicle airbag is established in order to clarify the interaction between occupants and airbags, and further a fast design and optimization method of airbags in the concept design phase is made based on the proposed theoretical model. First, the theoretical expression of the simplified mechanical relationship between the airbag＇s design parameters and the occupant response is developed based on classical mechanics, then the momentum theorem and the ideal gas state equation are adopted to illustrate the relationship between airbag＇s design parameters and occupant response. By using MATLAB software, the iterative algorithm method and discrete variables are applied to the solution of the proposed theoretical model with a random input in a certain scope. And validations by MADYMO software prove the validity and accuracy of this theoretical model in two principal design parameters, the inflated gas mass and vent diameter, within a regular range. This research contributes to a deeper comprehension of the relation between occupants and airbags, further a fast design and optimization method for airbags＇ principal parameters in the concept design phase, and provides the range of the airbag＇s initial design parameters for the subsequent CAE simulations and actual tests.展开更多
The restraint intensity （RI） of the pipeline girth welding joint was investigated using finite element method and experimental method to predict the cold cracking susceptibility of pipeline steel. The distribution o...The restraint intensity （RI） of the pipeline girth welding joint was investigated using finite element method and experimental method to predict the cold cracking susceptibility of pipeline steel. The distribution of RI along the girth weld was investigated to study the influence of welding position on the RL Subsequently, the effects of outer diameter （OD） and wall thickness of pipeline on the RI were studied with ABAQUS software. The results show that the RI is almost independent of welding position. The RI increased with the increasing wall thickness but decreased with the increasing OD. A prediction model of Rl was developed based on the effects of the OD and the wall thickness. It has been found that the predicted RIs were in good agreement with the experimental values. The maximum fractional error between the predicted RI and the experimental values was just about 10%. h was indicated that the errors were mainly caused by the heterogeneous of the weld bead.展开更多
基金supported by National Natural Science Foundation of China (Grant No. 51075180)Open Foundation of State Key Laboratory of Vehicle NVH and Safety Technology of China (Grant No.NVHSKL-201013)
文摘Throughout the vehicle crash event, the interactions between vehicle, occupant, restraint system (VOR) are complicated and highly non-linear. CAE and physical tests are the most widely used in vehicle passive safety development, but they can only be done with the detailed 3D model or physical samples. Often some design errors and imperfections are difficult to correct at that time, and a large amount of time will be needed. A restraint system concept design approach which based on single-degree-of-freedom occupant-vehicle model (SDOF) is proposed in this paper. The interactions between the restraint system parameters and the occupant responses in a crash are studied from the view of mechanics and energy. The discrete input and the iterative algorithm method are applied to the SDOF model to get the occupant responses quickly for arbitrary excitations (impact pulse) by MATLAB. By studying the relationships between the ridedown efficiency, the restraint stiffness, and the occupant response, the design principle of the restraint stiffness aiming to reduce occupant injury level during conceptual design is represented. Higher ridedown efficiency means more occupant energy absorbed by the vehicle, but the research result shows that higher ridedown efficiency does not mean lower occupant injury level. A proper restraint system design principle depends on two aspects. On one hand,the restraint system should lead to as high ridedown efficiency as possible, and at the same time, the restraint system should maximize use of the survival space to reduce the occupant deceleration level. As an example, an optimization of a passenger vehicle restraint system is designed by the concept design method above, and the final results are validated by MADYMO, which is the most widely used software in restraint system design, and the sled test. Consequently, a guideline and method for the occupant restraint system concept design is established in this paper.
基金We acknowledge this paper was supported by the program of Key Specialty of TCM Nursing of Guangzhou City,which aims to enrich theoretical content of mental health nursing
文摘Objective: Physical restraint is frequently used in medical services,such as in mental health settings,intensive care units and nursing homes,but its nature varies in different institutions.By reviewing related literature,this study aims to clarify the concept of physical restraint in mental health nursing.Method: Three databases (PubMed,PsyclNFO and CINAHL) were retrieved,and Walker and Avant's concept analysis method was used to analyze the concept of physical restraint in mental health nursing.Results: Physical restraint is a coercive approach that enables the administration of necessary treatment by safely reducing the patient's physical movement.It should be the last option used by qualified personnel.Antecedents of physical restraint are improper behavior (violence and disturbance) of patients,medical assessment prior to implementation and legislation governing clinical usage.Consequences of physical restraint are alleviation of conflict,physical injury,mental trauma and invisible impact on the institution.Discussion: This study defined the characteristics of physical restraint in mental health nursing.The proposed concept analysis provided theoretical foundation for future studies.
基金Supported by National Natural Science Foundation of China(Grant No.51375203)Open Foundation of Zhejiang Province Key Laboratory of Automobile Safety of China(Grant No.LHY1308J00368)Changchun Municipal Science and Technology Planning Project of China(Grant No.12ZX79)
文摘The current design and optimization of the occupant restraint system（ORS） are based on numerous actual tests and mathematic simulations. These two methods are overly time-consuming and complex for the concept design phase of the ORS, though they＇re quite effective and accurate. Therefore, a fast and directive method of the design and optimization is needed in the concept design phase of the ORS. Since the airbag system is a crucial part of the ORS, in this paper, a theoretical model for the vehicle airbag is established in order to clarify the interaction between occupants and airbags, and further a fast design and optimization method of airbags in the concept design phase is made based on the proposed theoretical model. First, the theoretical expression of the simplified mechanical relationship between the airbag＇s design parameters and the occupant response is developed based on classical mechanics, then the momentum theorem and the ideal gas state equation are adopted to illustrate the relationship between airbag＇s design parameters and occupant response. By using MATLAB software, the iterative algorithm method and discrete variables are applied to the solution of the proposed theoretical model with a random input in a certain scope. And validations by MADYMO software prove the validity and accuracy of this theoretical model in two principal design parameters, the inflated gas mass and vent diameter, within a regular range. This research contributes to a deeper comprehension of the relation between occupants and airbags, further a fast design and optimization method for airbags＇ principal parameters in the concept design phase, and provides the range of the airbag＇s initial design parameters for the subsequent CAE simulations and actual tests.
基金financially supported by the Tianjin Natural Science Foundation(No.11JCYBJC06000)the Key Project of Tianjin Municipal Science and Technology Support Program(No.11ZCGYSF00100)the Gansu Province Science and Technology Support Program(No.1204GKCA007)
文摘The restraint intensity （RI） of the pipeline girth welding joint was investigated using finite element method and experimental method to predict the cold cracking susceptibility of pipeline steel. The distribution of RI along the girth weld was investigated to study the influence of welding position on the RL Subsequently, the effects of outer diameter （OD） and wall thickness of pipeline on the RI were studied with ABAQUS software. The results show that the RI is almost independent of welding position. The RI increased with the increasing wall thickness but decreased with the increasing OD. A prediction model of Rl was developed based on the effects of the OD and the wall thickness. It has been found that the predicted RIs were in good agreement with the experimental values. The maximum fractional error between the predicted RI and the experimental values was just about 10%. h was indicated that the errors were mainly caused by the heterogeneous of the weld bead.
