风机锚杆松弛对基础局压混凝土疲劳损伤的影响分析

Impact analysis of wind turbine bolt looseness on fatigue damage of foundation partial pressure concrete

为了对特定状态下风机构件疲劳损伤发展进行有效评估,以维持风机平稳运转,通过ABAQUS有限元软件建立起风机基础精细化整体模型,对锚杆松弛发育过程进行模拟,探究了疲劳荷载工况下局压混凝土的应力分布与变化规律,并采用德国劳埃德船级社推荐规范(GL)中混凝土疲劳计算方法对局压混凝土热点开展了疲劳寿命评估。结果表明:1)风机锚杆松弛会影响局压混凝土的应力分布,背风侧混凝土应力集中会更加突出,且应力会随着锚杆松弛加剧而同步增大,因此可将背风侧混凝土的受力情况作为锚杆松弛程度的判断依据;2)综合参考风机结构混凝土疲劳抗压强度设计值和疲劳寿命期望值2项指标评判后显示,锚杆松弛达到8%时,局压混凝土极有可能发生压碎失效,应当及时对松弛锚杆复加预紧力,避免锚杆松弛恶化发展。研究得到的锚杆松弛下风机基础局压混凝土的疲劳损伤规律,可为其在实际工程中的安全运维提供数据支撑。

In order to effectively evaluate the fatigue damage development of wind turbine components under specific conditions and maintain smooth operation of the wind turbine,a refined overall model of wind turbine foundation was established by ABAQUS finite element software to simulate the development process of anchor bolt relaxation,revealing that the stress distribution and variation law of partial pressure concrete of the central situation under fatigue load conditions.The fatigue life evaluation of the hot spots of partial pressure concrete was carried out by using the concrete fatigue calculation method in the recommended code of Germanischer Lloyd(GL).The results show that:1)The relaxation of the wind turbine anchor can affect the stress distribution of the partial pressure concrete,the stress concentration of the concrete on the leeward side is more prominent,and the stress increases synchronously with the increase of the anchor relaxation.Therefore,the stress on the leeward side concrete can be used as a basis for determining the degree of anchor relaxation.2)Based on the comprehensive evaluation of two indicators,namely the design value of the fatigue compressive strength of the fan structure concrete and the expected value of the fatigue life,it can be pointed out that when the relaxation of the anchor reaches 8%,the partial pressure concrete is very likely to occur.In case of crushing failure,the preload should be added to the loose bolt in time to avoid the deterioration and development of the loose bolt.The research points out the fatigue damage law of the partial compression concrete of the fan foundation under the anchor bolt relaxation,which can provide data support for its safe operation and maintenance in actual engineering.