The effects of aging treatments on the tensile properties and compressive behavior of a thin-walled 6005 aluminum alloy tube were studied.Samples after three natural aging(NA)conditions were subsequently aged at 180℃...The effects of aging treatments on the tensile properties and compressive behavior of a thin-walled 6005 aluminum alloy tube were studied.Samples after three natural aging(NA)conditions were subsequently aged at 180℃ for 0.5−12.0 h artificial aging(AA).Tensile and compressive tests were performed after AA.The results show that for samples with the same NA,the longer the AA time is,the higher the strengths alloy owns,and at the same time the material shows a much lower elongation and faster process from plastic deformation to fracture.However,with NA prolonging,the alloy exhibits much better plastic deformation ability after AA,though its strength is decreased.The major cause of strength and plasticity variation induced by changing NA time is that the size of the main strengtheningβ''precipitates is larger and the density is lower.This character is evaluated by the strain hardening exponent n.Compressive results show that the optimum energy absorption characteristics can be acquired at a moderate n(14<n<17).Large n(n≥18)results in the fracture of tube during axial compression while low n(n≤13)causes lower energy absorption.展开更多
风电机组一般通过综合惯量控制提供辅助调频,然而其调频效果受控制参数影响较大。文中综合考虑风电机组自身可调能力与系统频率响应指标,对风电调频参数整定进行研究。首先,建立计及风电和火电参与调频的系统频率响应(system frequency ...风电机组一般通过综合惯量控制提供辅助调频,然而其调频效果受控制参数影响较大。文中综合考虑风电机组自身可调能力与系统频率响应指标,对风电调频参数整定进行研究。首先,建立计及风电和火电参与调频的系统频率响应(system frequency response,SFR)模型,并推导频率响应指标的解析式。其次,对风电机组的转子运动方程进行线性化并建立转速模型,在不同风速工况下验证其准确性。然后,以提升系统频率最低点为目标,同时考虑风电机组转速下限和系统频率安全约束,整定其控制参数。最后,仿真结果验证所提风电调频控制参数整定方法在不同风电渗透率以及功率扰动下,均能够在确保系统频率安全的前提下充分利用风电机组的转子动能。展开更多
基金Project(2019JJ50054)supported by the Natural Science Foundation of Hunan Province,ChinaProjects(51975201,U1664252)supported by the National Natural Science Foundation of China。
文摘The effects of aging treatments on the tensile properties and compressive behavior of a thin-walled 6005 aluminum alloy tube were studied.Samples after three natural aging(NA)conditions were subsequently aged at 180℃ for 0.5−12.0 h artificial aging(AA).Tensile and compressive tests were performed after AA.The results show that for samples with the same NA,the longer the AA time is,the higher the strengths alloy owns,and at the same time the material shows a much lower elongation and faster process from plastic deformation to fracture.However,with NA prolonging,the alloy exhibits much better plastic deformation ability after AA,though its strength is decreased.The major cause of strength and plasticity variation induced by changing NA time is that the size of the main strengtheningβ''precipitates is larger and the density is lower.This character is evaluated by the strain hardening exponent n.Compressive results show that the optimum energy absorption characteristics can be acquired at a moderate n(14<n<17).Large n(n≥18)results in the fracture of tube during axial compression while low n(n≤13)causes lower energy absorption.
文摘风电机组一般通过综合惯量控制提供辅助调频,然而其调频效果受控制参数影响较大。文中综合考虑风电机组自身可调能力与系统频率响应指标,对风电调频参数整定进行研究。首先,建立计及风电和火电参与调频的系统频率响应(system frequency response,SFR)模型,并推导频率响应指标的解析式。其次,对风电机组的转子运动方程进行线性化并建立转速模型,在不同风速工况下验证其准确性。然后,以提升系统频率最低点为目标,同时考虑风电机组转速下限和系统频率安全约束,整定其控制参数。最后,仿真结果验证所提风电调频控制参数整定方法在不同风电渗透率以及功率扰动下,均能够在确保系统频率安全的前提下充分利用风电机组的转子动能。
