高温后木材物理力学性能试验研究
发布时间：2018-11-29 12:24
【摘要】：我国现存有大量历史悠久的木结构古建筑,她们具有极其重要的历史文物价值,将其久远传承是一项艰巨任务。由于结构所用木材的易燃性,使得大量宏伟木结构古建筑在火灾中消失或毁坏,如著名的阿房宫、圆明园等。在对非严重烧毁的古建筑进行修复加固时,考虑到古建筑须遵循“不改变文物原状、修旧如旧”的修复原则,通常对受火灾影响较轻的木构件继续使用,而此时木材经火灾的高温后其物理力学性能将发生显著变化,因此掌握高温后木材的各项物理力学性能显得尤为重要。本文以我国古建筑木结构常用树种落叶松为研究对象,通过试验研究了高温后落叶松材的主要物理力学性能及温度、恒温时间、降温方式对其物理力学性能的影响规律。主要研究结论如下:(1)高温对木材的含水率、失重率及外观颜色均有很大影响。随着温度的升高和恒温时间的延长,木材的含水率呈降低趋势;木材的质量损失呈递增现象;木材外观颜色由浅褐色逐渐变为深褐色,其中200℃-250℃是木材颜色显著变化的温度区段。(2)高温后木材的各项力学性能[顺纹抗压强度、顺纹抗压弹性模量、顺纹抗拉强度、顺纹抗剪强度(弦面)、横纹抗压强度(全表面,径向)、横纹抗压弹性模量(径向)]均有不同程度降低,降低程度受温度、恒温时间和降温方式的影响,其中温度是最主要的影响因素。(3)在试验研究的基础上建立了高温后木材顺纹抗拉本构方程、顺纹抗压本构方程、横纹抗压本构方程。
[Abstract]:There are a large number of ancient wooden structures with a long history in our country, they have extremely important historical relics value, it is a difficult task to inherit them for a long time. Because of the flammability of the wood used in the structure, a large number of magnificent wooden structures disappeared or destroyed in the fire, such as the famous A Fang Gong, Old Summer Palace and so on. Taking into account the principle of "no change in the original state of cultural relics, repair as old", taking into account the principle of "no change in the original state of cultural relics," in the restoration and reinforcement of ancient buildings that are not severely burned, and generally continue to use wood elements that are less affected by fire, At this time, the physical and mechanical properties of wood will change significantly after the fire, so it is very important to master the physical and mechanical properties of wood after high temperature. In this paper, the main physical and mechanical properties of larch timber after high temperature and the influence of temperature, time of constant temperature and cooling mode on its physical and mechanical properties were studied. The main conclusions are as follows: (1) High temperature has great influence on wood moisture content, weight loss rate and appearance color. With the increase of temperature and the prolongation of the time of constant temperature, the moisture content of wood decreased and the loss of wood mass increased. The appearance color of wood gradually changed from light brown to dark brown, in which 200 鈩，
本文编号：2364988
[Abstract]:There are a large number of ancient wooden structures with a long history in our country, they have extremely important historical relics value, it is a difficult task to inherit them for a long time. Because of the flammability of the wood used in the structure, a large number of magnificent wooden structures disappeared or destroyed in the fire, such as the famous A Fang Gong, Old Summer Palace and so on. Taking into account the principle of "no change in the original state of cultural relics, repair as old", taking into account the principle of "no change in the original state of cultural relics," in the restoration and reinforcement of ancient buildings that are not severely burned, and generally continue to use wood elements that are less affected by fire, At this time, the physical and mechanical properties of wood will change significantly after the fire, so it is very important to master the physical and mechanical properties of wood after high temperature. In this paper, the main physical and mechanical properties of larch timber after high temperature and the influence of temperature, time of constant temperature and cooling mode on its physical and mechanical properties were studied. The main conclusions are as follows: (1) High temperature has great influence on wood moisture content, weight loss rate and appearance color. With the increase of temperature and the prolongation of the time of constant temperature, the moisture content of wood decreased and the loss of wood mass increased. The appearance color of wood gradually changed from light brown to dark brown, in which 200 鈩，
本文编号：2364988
本文链接：https://www.wllwen.com/jingjilunwen/jianzhujingjilunwen/2364988.html
