【摘要】 为了研究长期温湿度变化环境对木构件持续荷载效应的影响,将温湿度的长期变化视为木构件的外部荷载,在已有强度损伤累积模型基础上,采用miner线性损伤累积理论,通过数值分析方法建立了同时考虑日温湿度变化和年温湿度变化的长期荷载作用下木构件的强度损伤累积模型,并积分得到了材料强度衰减模型.结果表明:以年为时间单位的长期强度损伤累积模型保留了Gerhards模型的指数形式,大大提高了计算效率;材料强度衰减模型反映长期荷载作用下木构件强度的时变规律,便于采用抗力理论对历史建筑木结构进行剩余寿命预测;应用本文建立的模型对某历史建筑木桁架进行的剩余寿命预测验证了该模型的可行性和合理性.更多还原

【Abstract】 Long-term hygrothermal effects on the mechanical properties of a timber member have been investigated.A cumulative damage model was used where the hygrothermal variations were regarded as an external load upon the structural lumber of a mine liner.Both daily and annual hygrothermal changes were considered in the cumulative-damage numerical model.Long-time degradation in strength was obtained by integrating the numerical model.The results show that long-term cumulative damage maintains the exponential form of the Gerhards model.The numerical model provides a sound analysis.The strength of a timber under long-term loading is given by the strength degeneracy model.The residual service life of an historic timber structure may be easily predicted with the resistance theory.The feasibility and reliability of the proposed approach are verified.更多还原