古塔变形的数学模型古塔模型变形数学建模.docx
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古塔变形的数学模型古塔模型变形数学建模
古塔变形的数学模型古塔模型变形数学建模
古塔变形的数学模型
摘要
古塔被誉为中国古代杰出的高层建筑物,历史悠久,值得并需要我们的保护。
本文研究了关于古塔变形的问题,古塔的变形与塔身的中心紧密相关,具体分析了古塔倾斜、弯曲、扭曲的变形情况及趋势。
对于问题一,建立中心位置模型,采用多边形组合形心的算法,求的结果是表6,7,8,9中的数据;
对于问题二,我们将古塔的倾斜、弯曲和扭曲等变形情况,分别给予合理的
,即塔尖与底层中心的水平距离与塔高的比值;对于弯曲变形,我们定义了弯曲率K,即用中心点所拟合出的空间曲线的曲率来描述古塔各处弯曲率;对于扭曲变形,我们定义了相对扭曲度,利用坐标的旋转变换角度描述古塔的扭曲变形情况。
利用空间曲线拟合、坐标变换等方法以及MATLAB程序,分别求出了三个变形刻画量的量化指标。
对于问题三,我们考虑通过古塔的倾斜、弯曲及扭曲程度来分析古塔的变形趋势,由于数据较少,我们利用灰色预测法来分析这三种变形,利用matlab得到的数据来分析古塔的变形趋势
关键词:
关键词:
组合图形的形心拟合中心变形曲线灰色预测
一(问题重述
古塔由于长时间承受自重、气温、风力等各种作用,偶然还要受地震、飓风的影响会产生各种变形,诸如倾斜、弯曲、扭曲等。
为保护古塔,文物部门需适时对古塔进行观测,了解各种变形量,以制定必要的保护措施。
现有一古塔已上千年历史,是我国重点保护文物。
管理部门委托测绘公司先后于1986年7月、1996年8月、2009年3月和2011年3月对该塔进行了4次观测。
请根据题目提供的4次观测数据,讨论以下问题:
1.给出确定古塔各层中心位置的通用方法,并列表给出各次测量的古塔各层中心坐标。
2.分析该塔倾斜、弯曲、扭曲等变形情况。
3.分析该塔的变形趋势。
二、模型假设
1,参照中国古塔的塔身样式假设塔身水平面是正八角形;
2,假设古塔是均质物体,形心就是中心;
3,以地平面为X轴,建立空间直角坐标系X,Y,Z;
4,假设塔尖面积极小,近视为一个点;
5,假设模型4中古塔所在地不存在地震等这种偶然事件;
6,假设古塔所在的地平面是水平面。
三、符号说明
C--第i个三角形的形心(i=1,2,……6);i2S--第i个三角形的面积(单位:
m)(i=1,2,……6);i
A--第i个三角形的形心坐标(单位:
m);i
W--第t年塔身的倾斜角(t=1986,1996,2009,2011);t
D--第t年塔身在地面上的水平投影(t=1986,1996,2009,2011);t
H--第t年塔上部与下部的相对位移(t=1986,1996,2009,2011);t
L--第t年塔的拟合直线(t=1986,1996,2009,2011);t
R--塔的倾斜率;
m--第t年中心直线x轴的法向量(t=1986,1996,2009,2011);t
n--第t年中心直线y轴的法向量(t=1986,1996,2009,2011);t
J--第t年的中心直线方向向量(t=1986,1996,2009,2011);t
K--塔的曲率;
四、模型准备
(1)给数据用图像形式表现出来题目所给的4次观测数据1986年、1996年塔13层的第五个点数据残缺。
参照其10层、11层、12层的数据知道第五个点的数值在第四个点和第六个点的数值之间,另外分析后发现这两组数据对题目结果的影响不大。
因此结合实际和理论,采取取相邻年份该层的第四个点和第六个点的平均值将两组数据补齐。
(2)用MATLAB软件将题中所给数据及补充的数据画图表现出来。
五、模型的建立与求解
问题一
塔的变形趋势与塔身的中心有关,因此本题的主要目标是计算出塔中心的变化规律。
问题1属于计算多边形组合形心的数学问题。
因为1986年受自然、社会影响度较小,最接近古塔的原始图样,所以图形较为有参考价值,用MATLAB画出1986年塔身的大致图样为八边形,通过假设得出正多边形的形心就是中心,因
此可运用组合图形形心公式计算出古塔各层中心坐标。
问题一求古塔各层中心坐标,通过假设知道实质就是计算正多边形的中心,运用组合图形求形心的方法。
将每层正八边形的塔面都分为六个三角形(图1-2)S、S、S、S、S、S,123456
每年各层六个三角形的形心:
y,y,yx,x,x128128C()、133,
x,x,xy,y,y238238
C(,)、233
x,x,xy,y,y348348C(,)、333
y,y,yx,x,x478478C(,)、433
y,y,yx,x,x476476C(,)、335
x,x,xy4,y6,y5465
),C(633
代入测量数据,用excel得出:
1986
1986年各层分面积的形心
A1A2A3A4A5A6塔层
坐标(m)
567.8320,565.6707,564.3160,565.1133,570.8977,570.3780,1525.6177526.9707524.7823523.6693523.7220520.4057
565.7107,564.4383,565.2177,567.8177,570.7933,570.3203,2526.7563524.6417523.5770525.4710523.6700520.4773
565.7503,564.5587,565.3203,567.8037,567.6070,567.1797,3526.5460524.5040523.4870525.3273524.0603520.9890
565.7813,564.6540,565.4017,567.7920,570.6087,570.2180,4526.3787524.3940523.4147525.2127523.5783520.6037
565.8150,564.7567,565.4893,567.7800,570.5210,570.1693,5526.1987524.2760523.3370525.0893523.5347520.6640
565.8483,564.8583,565.5757,567.2693,570.4320,570.1233,6526.0230524.1610523.2620524.9697523.4920520.7217
565.9323,565.0030,565.6087,568.3457,568.9073,567.9333,7525.8013524.0360522.1230522.8950520.9863519.2110
566.0143,565.1437,565.7230,568.2910,568.8363,567.9370,8525.5857523.9140522.1233522.8597521.0700519.4030
566.0963,565.2862,565.8408,568.2398,568.7700,567.9455,9525.3700523.7907522.1207522.8213521.1480519.7718
566.1781,565.4221,565.9518,568.1901,568.7034,567.9501,10525.1621523.6731522.1205522.7871521.2268519.7718
566.2173,565.3411,565.9963,568.1775,568.6384,567.9245,11525.1621522.7775522.1686522.8075521.1750519.9055
566.4234,565.7663,566.2073,568.1537,568.5723,567.8977,12524.7179523.4303522.0879522.6799521.3238520.0395
566.5415,565.9325,566.3304,568.1358,568.5088,568.5314,13524.5037523.3134522.0724522.6281521.3708521.3482
1996
1996年各层分面积的形心
A1A2A3A4A5A6塔层
坐标(m)
565.6709,564.3162,564.8909,568.4069,568.9919,567.6595,1526.9704524.7820522.3034523.1387520.6390518.4570
565.7116,564.4392,564.9537,568.3784,567.0461,567.7212,2526.7554524.6499522.2315523.0668520.8848518.5824
565.7519,564.5603,565.1606,568.4056,568.9876,567.7816,3526.5444524.5024522.2207523.0441520.7551518.2057
565.7835,564.6562,565.2669,568.4048,568.9855,567.8299,4526.3765524.3918522.1878523.0065520.8005518.8035
565.8178,564.7594,567.2741,566.4548,568.5384,570.4308,5526.1958524.2731521.0509524.1346524.6946523.5249
563.6743,565.4214,567.3460,566.5451,568.4659,570.2377,6521.6294520.6144521.1294523.9446524.4789523.4745
563.8114,565.5112,565.6125,568.3495,568.9111,567.9371,7521.6232520.6525522.1191522.8911520.9825519.2071
566.0185,565.1478,565.7272,568.2953,568.8405,567.9412,8525.5814523.9097522.1190522.8554521.0657519.3987
564.2483,565.7973,567.4596,566.6890,568.2713,567.9455,9521.6049520.7773521.2459523.6426522.7973519.5893
564.4428,565.9130,567.4925,566.7358,568.327,569.2540,10521.5880520.7977521.2496523.5298524.0022523.2009
564.6655,566.0338,567.5067,566.6366,568.3226,569.7207,11521.5956520.8531521.2830523.4134523.8619523.1170
564.8876,566.1544,567.5207,566.9068,568.2923,569.5873,12521.6031520.9094521.3166523.2978523.7225523.0337
565.1091,566.2779,567.5416,566.9817,568.2704,569.4667,13521.6032520.9556521.3413523.1791523.5812522.9465
2009
2009年各层分面积的形心
A1A2A3A4A5A6塔层
坐标(m)
562.4995,564.6728,567.1635,566.2995,568.7379,570.9705,1521.6767520.3384520.9321524.4607525.0660523.7300
562.7235,564.8138,567.1945,569.5556,569.5059,570.8206,2521.6673520.3847520.9648521.5574523.8796523.6727
562.9424,564.9515,567.2241,566.3847,568.6415,570.6734,3521.6587520.4308520.9976524.2815524.8619523.6173
563.1175,565.0616,567.2484,566.4188,568.5920,570.5565,4521.6513520.4670521.0232524.2100524.7807523.5727
563.3050,565.1797,567.2741,566.4548,568.5384,570.4308,5521.6439520.5062521.0509524.1346524.6946523.5249
563.6743,656.4214,567.3460,566.5451,568.4659,570.2377,6521.6294520.6144521.1294523.9446524.4789523.4345
563.8114,565.5112,567.3735,566.5799,568.4390,570.1656,7521.6232520.6525521.1561523.8915524.3948523.3980
564.0303,565.6546,567.4165,566.6344,568.3961,570.0504,8521.6142520.7151521.2012523.7572524.2642523.3433
564.2483,565.7973,567.4596,566.6890,568.3533,569.9357,9521.6049520.7773521.2459523.6426524.1329523.2876
564.4428,565.9130,567.4925,566.7658,568.3527,569.8540,10521.5880520.7977521.2496523.5298524.0022523.2007
564.6655,566.0338,567.5067,566.8366,568.3226,569.7207,11521.5955520.8535521.2830523.4134523.8619523.1170
564.8876,566.1544,567.5207,566.9068,568.2923,569.5873,12521.6031520.9094520.3166523.2978523.7225523.0337
565.1091,566.2779,567.5416,566.9817,568.2704,569.4667,13521.6032520.9556521.3413523.1791523.5812522.9465
2011
2011年各层分面积的形心
A1A2A3A4A5A6塔层
坐标(m)
562.49957,564.6856,564.6730,567.1637,567.1413,568.4800,1521.67665204421520.3383520.9320520.9436523.1363
562.7237,564.8140,567.1947,566.3432,568.7042,570.8208,2521.6671520.3844520.9645524.3695524.9621523.6725
562.9428,564.9518,567.2245,566.3851,568.6419,570.6737,3521.6591520.4312520.9979524.2819524.8622523.61764563.1179,565.0620,567.2488,566.4192,568.5924,570.5569,
521.6509520.4666521.0227524.2096524.7802523.5722
563.3056,565.1803,567.2747,566.4554,568.5391,570.4314,5521.6433520.5056521.0503524.1339524.6939523.5243
563.6750,565.4221,567.3467,566.5458,568.4666,570.2384,6521.6286520.6136521.1287523.9439524.4782523.4338
563.8122,565.5120,567.3743,566.5807,568.4398,570.1664,7521.6224520.6517521.1553523.8707524.3940523.3972
564.0311,565.6554,567.4173,566.6352,568.3969,570.0512,8521.6133520.7142521.2003523.7563524.2633523.3424
564.2493,564.7983,567.4607,566.6899,568.3543,569.9366,9521.6040520.7764521.3884523.1730523.6633522.8180
564.4439,565.9141,567.4936,566.7669,568.3538,569.8551,10521.5869520.7966521.2485523.5287524.0011523.1996
564.666,566.0349,567.5078,566.8377,568.3237,569.7218,11521.5944520.8524521.2819523.4123523.8607523.1159
564.8889,566.1557,567.5220,566.9081,568.2936,569.5886,12521.6018520.9081521.3153523.2965523.7212523.0324
565.1104,566.2792,567.5429,566.9830,568.2717,569.4680,13521.6018520.9542521.3398523.1777523.5797522.9450
每层六个三角形的面积S、S、S、S、S、S,代入测量数据,运行MATLAB123456
软件得出:
13层塔中各层划分后的三角形面积
S1S2S3S4S5S6塔层
面积(m2)
16.106714.639720.606821.002514.70746.256325.730713.640219.066219.390213.58645.839735.370612.696217.612117.869412.535.446145.099511.970216.501616.705911.72115.140554.813711.214115.350915.505810.87774.822864.538710.502914.256414.389210.14.523974.059.267212.639112.73328.92594.002883.6.268.13911.158211.21717.85133.528293.17897.08179.77769.80146.84873.0811102.80146.16058.55718.54015.96732.6792112.47635.34497.53127.4125.23612.3588122.16844.58736.56476.36134.558372.0604131.89313.90795.69685.42383.93922.6792
多边形的形心(x,y,z)公式:
ccc
sx,sx,sx,sx,sx,sxCCCCCC123456123456x,cs,s,s,s,s,s123456
sy,sy,sy,sy,sy,syCCCCCC123456123456y,cs,s,s,s,s,s123456
Z,Z,Z,Z,Z,ZCCCCCC123456Z,C6
将表1,2,3,4,5中的数据代入形心公式中,excel计算的结果如下1986
1986年塔的中心坐标
XcYcZc塔层
坐标(m)
1567.1157524.37331.7874
2567.1355524.25837.3203
3566.38524.267212.7553
4567.6101523.857317.0783
5567.1858523.987921.7205
6567.2786523.784626.2351
7567.0062522.346129.8369
8566.9845522.506633.3509
9567.0212522.486836.8549
10567.0562522.470740.1721
11567.0363522.34644.4409
12567.1611522.389348.7119
13567.312522.402452.8293
1996
1996年塔的中心坐标
XcYcZc塔层
坐标(m)
1566.6531522.76061.7832566.3558522.69047.31463566.7792522.631712.75084566.6888523.089217.07515567.0364523.466621.7166567.04522.557926.22957566.9986522.132829.83238566.9059522.101133.34549566.8944521.920636.848310567.071522.304540.167611567.1643522.340144.435412567.2123522.299748.707413567.5044522.404552.8253
2009
2009年塔的中心坐标
XcYcZc塔层
坐标(m)
1566.7412522.70051.76452567.7195521.77797.3093566.8095522.643712.