Detection and Prediction of Internal Damage in the Ancient Timber Structure Based on Optimal Combined Model

Table 2

Results of two detection methods.

Working condition	Damaged proportion	Simulation type	Tree species	True value (cm^2)	Stress wave			Drilling resistance
					Detection value (cm^2)	Absolute error (cm^2)	Detected precision (%)	Detection value (cm^2)	Absolute error (cm^2)	Detected precision (%)
1	1/16	Hollow	Poplar (specimen 1)	26.13	37.22	11.09	57.6	21.34	4.79	81.7
2	1/8			52.27	70.59	18.32	65.0	44.12	8.15	84.4
3	1/4			104.54	124.64	20.10	80.8	95.02	9.52	90.9
4	1/32	Hollow	Elm (specimen 2)	12.20	3.90	8.30	32.0	7.47	4.73	61.2
5	1/16			24.40	15.61	8.79	64.0	18.02	6.38	73.9
6	1/8			48.80	58.55	9.75	80.0	39.49	9.31	80.9
7	1/4			97.59	109.3	11.71	88.0	88.08	9.51	90.3
8	1/2			195.18	202.98	7.80	96.0	184.03	11.15	94.3
9	1/32	Insect attacks	Poplar (specimen 3)	29.13	15.93	13.20	54.7	28.17	0.96	96.7
10	1/16			58.26	44.65	13.61	76.6	55.97	2.29	96.1
11	1/8			116.52	101.53	14.99	87.1	104.2	12.32	89.4
12	1/4			233.04	225.68	7.36	96.8	219.89	13.15	94.4
13	1/2			466.09	471.57	5.48	98.8	449.68	16.41	96.5
14	1/32	Insect attacks	Elm (specimen 4)	12.89	4.13	8.76	32.0	11.93	0.96	92.6
15	1/16			25.77	10.94	14.83	42.5	22.68	3.09	88.0
16	1/8			51.55	34.06	17.49	66.1	46.83	4.72	90.8
17	1/4			103.10	107.24	4.14	96.0	87.57	15.53	84.9
18	1/2			206.19	210.81	4.62	97.8	186.77	19.42	90.6
Average value						11.13	72.9		8.47	87.6