Cruciform joints in ships are prone to fatigue damage and the determination of type of weld plays a significant role in thefatigue design of the joint. In this paper, the effect of weld geometry on fatigue failure of ...Cruciform joints in ships are prone to fatigue damage and the determination of type of weld plays a significant role in thefatigue design of the joint. In this paper, the effect of weld geometry on fatigue failure of load carrying cruciform joints inships is investigated using Effective Notch Stress (ENS) approach. A fictitious notch of 1 mm radius is introduced at theweld root and toe and fatigue stress is evaluated. The effect of weld leg length (l) and weld penetration depth (p) on ENS atweld root and toe are determined. The critical weld leg length (lcr) at which fatigue failure transitions from weld root toweld toe is investigated. An approximation formula for determination of the critical weld leg length considering weldpenetration depth (p) is proposed.展开更多
According to the sampling statistics there are over 7 millions limb disabled persons in China from several times of those in the world. For the benefit to the amputees, thousands varies kinds of commencial Products of...According to the sampling statistics there are over 7 millions limb disabled persons in China from several times of those in the world. For the benefit to the amputees, thousands varies kinds of commencial Products of artificial hands, by scientific promotion have ben developed in the recent half century. Among those products the EMG controlling artificial upper limb brings the hope to the amputees. The later are now used widely form the earlest one in 1948.In 1978, Shanghai Jiao Tong University began to study and develop the EMG controlling artificial band mounted to amputes over thousand disabled during a couple of recent decades.The risidual muscles of an amputee are the signal source of the artificial hand controlled by EMG. The evoked EMG which can transmit the brain moving information is one of the bioelectricities from human body. The EMG signal, accumulated at skin surface with surface electrodes, passing through filtering and amplifying circuits controls the movement-this is the main principle of EMG controlling artificial hand.But, owing to the weakness of EMG (μv) and a group of muscles information plus the strong turbulence of electric field (v), the integrated EMG can’t completely reflect the brain moving act and will influence the accuracy of EMG-hand, especially those of the multi-multi-degree of freedom.In 1978, only 57% of the controlling aaccuracy of artificial hand with 3-degree of freedom could be reached by the Herbert’s research. In 80’s, the controlling accuracy raised up to 72% by Denning’s new method. Up to now, the accuracy is still not ideal, eventhrogh the Hi-tech of using pattern-recognitionand artincial neuro-net work. The electronic artificial hand will be considered successful and practical only with the moving accuracy more than 95%.Some research by using implant electrode for detecting the neuro-information or EEG controllingmethod met also dimculties for raising the accuracy of artificial hand.For breaking througll the threshold of accuracy limit, the EMG method as mentioned above must bechanged entirely, A newest creative research work on the electronic artificial hand controlled by a "regenerated finger" made by transplanting a toe to the stump is developing in Shanghai Jiao TongUniversity, which is without precedent in the world.The first experimental amputee using "regenerated finger’ to control an electronic artificial forearm with 3-degree of freedom reaches 100% accuracy of movements (i.e. no error within 100 tests). It has been proved that the use of a "regenerated finger" as a controlling signal command makes it possible to use the electronic artificeal hand with multi-degree of freedom without error Thecombining medical science with engineering in the area of designing an electronic artifical upper limb.Acknowledgement: The authors extend their hearty thanks to the famous academician Dr.Chen Zhongwei (Zhong-Sen Hospital) for their creative effort and successful micro-surgical operation for transplanting toe to stump of an amputee, also to the China Science Foundation for supporting. us the fund to develop this research.展开更多
文摘Cruciform joints in ships are prone to fatigue damage and the determination of type of weld plays a significant role in thefatigue design of the joint. In this paper, the effect of weld geometry on fatigue failure of load carrying cruciform joints inships is investigated using Effective Notch Stress (ENS) approach. A fictitious notch of 1 mm radius is introduced at theweld root and toe and fatigue stress is evaluated. The effect of weld leg length (l) and weld penetration depth (p) on ENS atweld root and toe are determined. The critical weld leg length (lcr) at which fatigue failure transitions from weld root toweld toe is investigated. An approximation formula for determination of the critical weld leg length considering weldpenetration depth (p) is proposed.
文摘According to the sampling statistics there are over 7 millions limb disabled persons in China from several times of those in the world. For the benefit to the amputees, thousands varies kinds of commencial Products of artificial hands, by scientific promotion have ben developed in the recent half century. Among those products the EMG controlling artificial upper limb brings the hope to the amputees. The later are now used widely form the earlest one in 1948.In 1978, Shanghai Jiao Tong University began to study and develop the EMG controlling artificial band mounted to amputes over thousand disabled during a couple of recent decades.The risidual muscles of an amputee are the signal source of the artificial hand controlled by EMG. The evoked EMG which can transmit the brain moving information is one of the bioelectricities from human body. The EMG signal, accumulated at skin surface with surface electrodes, passing through filtering and amplifying circuits controls the movement-this is the main principle of EMG controlling artificial hand.But, owing to the weakness of EMG (μv) and a group of muscles information plus the strong turbulence of electric field (v), the integrated EMG can’t completely reflect the brain moving act and will influence the accuracy of EMG-hand, especially those of the multi-multi-degree of freedom.In 1978, only 57% of the controlling aaccuracy of artificial hand with 3-degree of freedom could be reached by the Herbert’s research. In 80’s, the controlling accuracy raised up to 72% by Denning’s new method. Up to now, the accuracy is still not ideal, eventhrogh the Hi-tech of using pattern-recognitionand artincial neuro-net work. The electronic artificial hand will be considered successful and practical only with the moving accuracy more than 95%.Some research by using implant electrode for detecting the neuro-information or EEG controllingmethod met also dimculties for raising the accuracy of artificial hand.For breaking througll the threshold of accuracy limit, the EMG method as mentioned above must bechanged entirely, A newest creative research work on the electronic artificial hand controlled by a "regenerated finger" made by transplanting a toe to the stump is developing in Shanghai Jiao TongUniversity, which is without precedent in the world.The first experimental amputee using "regenerated finger’ to control an electronic artificial forearm with 3-degree of freedom reaches 100% accuracy of movements (i.e. no error within 100 tests). It has been proved that the use of a "regenerated finger" as a controlling signal command makes it possible to use the electronic artificeal hand with multi-degree of freedom without error Thecombining medical science with engineering in the area of designing an electronic artifical upper limb.Acknowledgement: The authors extend their hearty thanks to the famous academician Dr.Chen Zhongwei (Zhong-Sen Hospital) for their creative effort and successful micro-surgical operation for transplanting toe to stump of an amputee, also to the China Science Foundation for supporting. us the fund to develop this research.
