This paper is to review the theory of thin-walled beam structures of the open cross-section. There is scant information on the performance of structures made from thin-walled beam elements, particularly those of open ...This paper is to review the theory of thin-walled beam structures of the open cross-section. There is scant information on the performance of structures made from thin-walled beam elements, particularly those of open sections, where the behavior is considerably complicated by the coupling of tensile, bending and torsional loading modes. In the combined loading theory of thin-walled structures, it is useful to mention that for a thin-walled beam, the value of direct stress at a point on the cross-section depends on its position, the geometrical properties of the cross-section and the applied loading. This applies whether the thin-walled section is closed or open but this study will be directed primarily at the latter. Theoretical analyses of structures are fairly well established, considered in multi-various applications by many scientists. However, due to the present interest in lightweight structures, it is necessary to specify where the present theory lies. It does not, for example, deal with compression and the consequent failure modes under global and local buckling. Indeed, with the inclusion of strut buckling failure and any other unforeseen collapse modes, the need was perceived for further research into the subject. Presently, a survey of the published works has shown in the following: 1) The assumptions used in deriving the underlying theory of thin-walled beams are not clearly stated or easily understood;2) The transformations of a load system from arbitrary axis to those at the relevant centre of rotation are incomplete. Thus, an incorrect stress distribution may result in;3) Several methods are found in the recent literature for analyzing the behaviour of thin-walled open section beams under combined loading. These reveal the need appears for further study upon their torsion/flexural behaviour when referred to any arbitrary axis, a common case found in practice. This review covers the following areas: 1) Refinement to existing theory to clarify those observations made in 1 - 3 above;2) Derivation of a general elastic stiffness matrix for combined loading;3) Calculation of the stress distribution on the cross-section of a thin-walled beam. A general transformation matrix that accounts for a load system applied at an arbitrary point on the cross-section will be published in a future paper.展开更多
目的比较在中央肝切除术中肝断面胶封法处理与肝断面敞开处理的临床效果,探讨肝断面胶封法处理的临床应用价值。方法回顾性分析2020年1月至2024年12月温州医科大学附属第一医院肝胆胰外科56例行中央肝切除术患者的临床资料,根据肝断面...目的比较在中央肝切除术中肝断面胶封法处理与肝断面敞开处理的临床效果,探讨肝断面胶封法处理的临床应用价值。方法回顾性分析2020年1月至2024年12月温州医科大学附属第一医院肝胆胰外科56例行中央肝切除术患者的临床资料,根据肝断面处理方式分为两组:肝断面胶封法处理组(n=15)和肝断面敞开处理组(n=41),比较两组患者的短期临床结局和相关临床指标差异。结果两组均无手术死亡病例,未发生肝衰竭等严重并发症。肝断面胶封法处理组出现胸腔积液2例,无胆漏、创面渗血、创面感染病例;肝断面敞开处理组发生胆漏1例,胸腔积液3例,创面渗血2例,无创面感染病例。两组术后并发症发生率比较,差异无统计学意义[13.33%(2/15)vs 14.63%(6/41),P=0.678]。两组手术时间、术中出血量、肝门阻断时间比较,差异均无统计学意义(P>0.05)。肝断面胶封法处理组术后第1天[(118.67±75.77)mL vs 150.00(120.00,210.00)mL,Z=-2.124,P=0.034]、第2天[(107.00±38.63)mL vs 150.00(100.00,220.00)mL,Z=-2.628,P=0.009]、第3天[(65.67±41.18)mL vs 130.00(80.00,220.00)mL,Z=-3.661,P<0.001]腹腔引流量均显著少于肝断面敞开处理组。两组术后第1、3、7天的丙氨酸氨基转移酶(ALT)、总胆红素(TBIL)和肌酐(Cr)比较,差异均无统计学意义(P>0.05)。两组共40例患者于术后1个月左右再入院接受肝癌术后预防性经动脉化疗栓塞(TACE)治疗,影像学检查见肝实质强化均匀,保留肝脏血管系统显示清晰,门静脉系统、肝静脉系统均未见狭窄。结论肝断面胶封法处理操作简便、安全可靠,可有效减少中央肝切除术后早期腹腔积液。肝断面胶封法处理为中央肝切除术中肝断面处理提供了一种新的可选择方案。展开更多
文摘This paper is to review the theory of thin-walled beam structures of the open cross-section. There is scant information on the performance of structures made from thin-walled beam elements, particularly those of open sections, where the behavior is considerably complicated by the coupling of tensile, bending and torsional loading modes. In the combined loading theory of thin-walled structures, it is useful to mention that for a thin-walled beam, the value of direct stress at a point on the cross-section depends on its position, the geometrical properties of the cross-section and the applied loading. This applies whether the thin-walled section is closed or open but this study will be directed primarily at the latter. Theoretical analyses of structures are fairly well established, considered in multi-various applications by many scientists. However, due to the present interest in lightweight structures, it is necessary to specify where the present theory lies. It does not, for example, deal with compression and the consequent failure modes under global and local buckling. Indeed, with the inclusion of strut buckling failure and any other unforeseen collapse modes, the need was perceived for further research into the subject. Presently, a survey of the published works has shown in the following: 1) The assumptions used in deriving the underlying theory of thin-walled beams are not clearly stated or easily understood;2) The transformations of a load system from arbitrary axis to those at the relevant centre of rotation are incomplete. Thus, an incorrect stress distribution may result in;3) Several methods are found in the recent literature for analyzing the behaviour of thin-walled open section beams under combined loading. These reveal the need appears for further study upon their torsion/flexural behaviour when referred to any arbitrary axis, a common case found in practice. This review covers the following areas: 1) Refinement to existing theory to clarify those observations made in 1 - 3 above;2) Derivation of a general elastic stiffness matrix for combined loading;3) Calculation of the stress distribution on the cross-section of a thin-walled beam. A general transformation matrix that accounts for a load system applied at an arbitrary point on the cross-section will be published in a future paper.
文摘目的比较在中央肝切除术中肝断面胶封法处理与肝断面敞开处理的临床效果,探讨肝断面胶封法处理的临床应用价值。方法回顾性分析2020年1月至2024年12月温州医科大学附属第一医院肝胆胰外科56例行中央肝切除术患者的临床资料,根据肝断面处理方式分为两组:肝断面胶封法处理组(n=15)和肝断面敞开处理组(n=41),比较两组患者的短期临床结局和相关临床指标差异。结果两组均无手术死亡病例,未发生肝衰竭等严重并发症。肝断面胶封法处理组出现胸腔积液2例,无胆漏、创面渗血、创面感染病例;肝断面敞开处理组发生胆漏1例,胸腔积液3例,创面渗血2例,无创面感染病例。两组术后并发症发生率比较,差异无统计学意义[13.33%(2/15)vs 14.63%(6/41),P=0.678]。两组手术时间、术中出血量、肝门阻断时间比较,差异均无统计学意义(P>0.05)。肝断面胶封法处理组术后第1天[(118.67±75.77)mL vs 150.00(120.00,210.00)mL,Z=-2.124,P=0.034]、第2天[(107.00±38.63)mL vs 150.00(100.00,220.00)mL,Z=-2.628,P=0.009]、第3天[(65.67±41.18)mL vs 130.00(80.00,220.00)mL,Z=-3.661,P<0.001]腹腔引流量均显著少于肝断面敞开处理组。两组术后第1、3、7天的丙氨酸氨基转移酶(ALT)、总胆红素(TBIL)和肌酐(Cr)比较,差异均无统计学意义(P>0.05)。两组共40例患者于术后1个月左右再入院接受肝癌术后预防性经动脉化疗栓塞(TACE)治疗,影像学检查见肝实质强化均匀,保留肝脏血管系统显示清晰,门静脉系统、肝静脉系统均未见狭窄。结论肝断面胶封法处理操作简便、安全可靠,可有效减少中央肝切除术后早期腹腔积液。肝断面胶封法处理为中央肝切除术中肝断面处理提供了一种新的可选择方案。
