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• Hi,guys,

各位路人甲乙丙丁大家好

• In this episode, let's talk about the relationship between the force and objects ,

這集我們談力量與物體之間的關係

• first this blue is an object,

首先藍色這個是物體

• it has contains both are convex and concave,

它有包含了凸面和凹面

• and also relatively wider and narrower parts,

還有比較寬廣和狹窄的部分

• when after the concept of the objects enters, we will to produce the proportional scale,

當物體的概念進入後，我們會產生比例尺

• the unit is what that not the focus,

單位是什麼並非重點

• this an object is subjected to variety of different roles by the forces and moment couple now,

現在這個物體受到各種不同的力和力偶矩的作用

• so it produced a certain the deformation,

所以它產生了一定的變形

• and the dashed line is the object line after it's deformed,

而虛線就是它變形後的輪廓線

• maybe it still will start to moves or rotations after thrust surface,

也許它受力之後還會開始移動或轉動

• the force will causes objects the moves dip direction,

力量會使物體移動傾向...

• the moment couple will causes objects to have rotates dip direction,

力偶矩則使物體產生轉動傾向

• the soil mechanics did not use to the moment couple,

土壤力學並沒有用到力偶矩

• so it will not appear again after this episode appears.

所以在這集出現後就不再出現

• that, we consider of the objects are also not rotation occurs ,

而我們考慮的物體也都不會發生轉動

• because the soil will not rotation,

因土壤不會轉動

• ok, next let's take a look at the force.

好接下來我們來看一下力量

• first, we can see it withstand the concentrated force of F1

首先我們可以看到它承受F1的集中力

• and the force of F2

和F2的力量

• there are also f1 and f2

另外有f1和f2

• the uniform force and distributed force,

均佈力和分佈力

• that, let's explain the nouns now,

那現在我們來作名詞解釋

• focusing on role by the object on 1 point is called the concentrated force,

集中於物體1點上作用者稱作集中力

• the concentrated force can act on or outside the objects,

集中力可作用於物體上或物體之外

• can be understood as the force at a distance, (but actually is vector movement), that's no problem,

可以當作超距力理解(但其實是向量移動)，並無問題

• the force of unit we use is Newton N,

力量我們使用的單位是牛頓N

• the concentrated force actually is abstract concept,

集中力其實是抽象概念

• assume the force acts on a certain particle,

假定了力量作用在某一質點

• this particle doesn't exist in the real world,

此質點在現實世界中並不存在

• the force of real world must be demonstrated in the distributed force manner,

現實世界的力量一定是以分佈力的方式去展現

• even if you poke the potato with one needle,

哪怕你用一根針戳馬鈴薯

• the tip also has certain area,

針尖也是有一定的面積

• next, let's look at the distributed force,

接下來我們來看分佈力

• the distributed force can be called uniformity force in certain case,

分佈力在某個情況下可以稱作均佈力

• that is, it the same with role of "density"form on a certain acreage,

就是它在一定面積上作用的"密度"是一樣的

• that used here was is similar to the concept of density,

這裡使用的是類似於密度的概念

• the distributed force unit actually is how many Newtons is acts on per square meter,

分佈力單位其實是每平方公尺上面作用多少牛頓

• actually also is mean the how many Newtons is acts on each unit area,

其實也是每單位面積上作用多少牛頓的意思

• in fact, the distribution force can be equivalent to the concentrated force,

其實分佈力可以等效於集中力

• the equivalent manner is as follows:

等效方式如下：

• first to consider this the uniform force ,

先考慮此均佈力

• the density of the uniform force is f2

均佈力的密度是f2

• the interaction length is l2,

作用長度為l2

• what is the equivalent concentrated force of such a force?

如此的等效集中力是多少呢？

• write the concentrated force as the red arrow,

集中力寫成紅色箭頭

• it's value = f2 * l2

其值=f2*l2

• then multiply the unit area is 1

再乘上單位面積是1

• this 1 can be as length of paper surface prominence,

這個1可以當作突出紙面的長度

• we use angle of the three dimension to see is so

我們用三維的角度來看就是如此

• so it acts on an area,

所以它作用於一面積上

• the magnitude by the concentrated force is the volume of the rectangular parallelopiped,

集中力大小就是長方體體積

• i.e f2*l2*1

即f2*l2*1

• where is such a the concentrated force acting?

那這樣的集中力作用在哪裡呢？

• acting on above the centroid of the rectangle,

作用在長方型的形心上面

• the centroid is in the middle...so we draw the concentrated force right here,

形心在中間...所以我們把集中力畫在這裡

• point of application in about 1/2l2 the place,

作用點在大約1/2l2的地方

• another one distributed force is the triangle,

另外一個分佈力是三角形

• in fact, the distributed force can have any shape,

其實分佈力可以有任何形狀

• the triangle...that accordance with the rectangle,

三角形...就比照長方形

• the magnitude is the bottom multiplied by the height divided by two

大小就是底乘以高除以二

• point of application in 1/3l1 the place,

作用點位置在1/3l1的地方

• when in the exam, we used to take the uniform force

在考試的時候我們習慣把均佈力

• to calculates after change to the concentrated force,

改成集中力後再來計算

• because for the objects ,them are equivalent ,

因為它們對物體來說是等效的

• the so-called the equivalent is the same with the effect of generated,

所謂等效就是產生的效應是一樣的

• that let's consider a question now.

那我們現在來考慮一個問題

• what happens after an object is cuts ?

將物體切開以後會發生什麼事？

• we know the object is for the maintain its shape before the thrust surface,

我們知道物體為了維持自己受力前的形狀

• when subjected to external forces, internal forces are also will generated within the object,

當受外力的時候，物體內部也會產生內力

• so soil mechanics is defined...

所以力學就是定義了...

• the force that can be observed before cutting is the external force

切開前可觀察的力為外力

• the force that emerges after being cut is called the internal force.

切開後才顯現的力量叫作內力

• the internal force is actually very complicated,

內力其實非常的複雜

• and with the angle or way you cut,

而且隨著你切開的角度或方式

• the internal forces generated both are also different,

所產生的內力也都不一樣

• the internal forces must have appeard with form of distributed forces,

內力一定是以分佈力的形式出現

• it main can be divided into two types,

它主要可以分作兩種

• one is the normal stress and one is the tangential stress,

一種是正向應力，一種是剪應力

• the so-called the normal stress is the direction of stress vertical to the section,

所謂正向應力就是應力方向垂直於切面

• the so-called the tangential stress is the direction of stress parallel to the section,

所謂剪應力就是應力方向平行於切面

• such as red arrows

如紅色的箭頭

• the external force and internal force are gives to objects...

那外力和內力對於物體...

• effects produced are not the same,

產生的效應並不一樣

• what's the effects produced of the external force?

外力產生的效應是什麼呢？

• has movement, rotation, reaction force, work and so on ...

有移動、轉動、反作用力、作功...等等

• for the internal force, it will make the...

內力來說的話，它會使的...

• the stress in the object changes,

物體裡面的應力產生變化

• deformation, transformation energy...and so on.

變形、能量變化...等等

• for in soil mechanics...

在土壤力學來說...

• when the external force continue to increase in the case, the internal force will rise accordingly,

外力不斷增加的情況下，內力也會相應上升

• the normal stress in the soils will causes soil consolidation,

土壤內的正向應力會使的土壤壓密

• that is the density increases (strength rises),

也就是密度增加(強度上升)

• the increase of the tangential stress will make the the general shear failure of soils,

剪應力的上升則會使土壤剪力破壞

• the main form of soil damage is the general shear failure,

土壤主要的破壞形式就是剪力破壞

• finally, let's supplement the concept of "the rigid body",

最後我們來補充「剛體」的概念

• the rigid body is considered as the ideal objects for the internal effects are not exist.

剛體視為內效應不存在之理想物體

• can imagine the rigid body don't exist in the real world,

可以想見剛體並不存在於現實世界中

• within the subjects of engineering mechanics is

在工程力學的科目裡面

• the objects are all assumed be the rigid bodies,,

物體都被假設為剛體

• that is, only the effects of external and external effects are considered,

也就是只考慮外力和外效應的影響

• the material mechanics will considered of internal force the part,

而材料力學則會考慮內力的部分

• then the soil mechanics is builted on top of these two subjects,

土壤力學又建立在二科之上

• so the scope of consideration is will again broader,

所以考慮的面向又更廣了

• ok, the above is all the content today. Bye ~

以上就是今天全部的內容~~掰掰~~

Hi,guys,

B1 中級 中文 美國腔 物體 土壤 力學 作用 產生 面積

# 土壤力學 (Soil mechanics)

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WC 發佈於 2021 年 01 月 14 日