| 詞或詞組 | 中文 | 英文解釋中文解釋 |
|---|---|---|
| Lap joint | 搭接接頭 |
A riveted, welded, or bonded connection between two plates made by overlapping one plate above the other. Lap joints having plates above and below a butt joint avoid the bending moment associated with a simple lap joint. 兩塊板之間的鉚接、焊接或粘結連接，通過將一塊板重疊在另一塊板上而形成。對接接頭上方和下方具有板的搭接接頭避免了與簡單搭接接頭相關的彎矩。 |
| Laser hardening | 激光硬化 |
A surface-hardening process which uses a laser to quickly heat a surface. Heat conduction into the interior of the part will quickly cool the surface, leaving a shallow martensitic layer. Hardening of steel by a moving CO2?or Nd:YAG laser beam focussed down to a few mm in diameter. A point in the surface of an object is rapidly heated into the austenite range and then rapidly cooled to form tempered martensite. 一種使用激光快速加熱表面的表面硬化工藝。進入零件內部的熱傳導將快速冷卻表面，留下淺馬氏體層。通過移動CO2或Nd:YAG激光束使鋼硬化，激光束聚焦至直徑幾毫米。物體表面的一點迅速加熱到奧氏體范圍，然后迅速冷卻，形成回火馬氏體。 |
| Laser sintering | 激光燒結 |
A manufacturing technique by which parts are built layer by layer (each typically 20 μm thick) from plastic or metal (Direct Metal Laser Sintering, DMLS) material in powder form, each layer being sintered by a scanning laser. 一種制造技術，通過這種制造技術，零件由粉末形式的塑料或金屬（直接金屬激光燒結，DMLS）材料逐層（每個厚度通常為 20 微米）構建，每一層都由掃描激光燒結。 |
| Latent heat | 潛熱 |
Thermal energy absorbed or released when a substance undergoes a phase change. 物質發生相變時吸收或釋放的熱能。 |
| Lathe | 車床 |
A machine tool in which work, gripped in the headstock, is rotated against the cutting tool to produce turned, bored, faced, or threaded components. 一種機床，其中夾持在主軸箱中的工件靠著切削工具旋轉，以生產車削、鉆孔、端面或螺紋部件。 |
| Lead angle | 導角 |
The angle of the helix of a screw thread or worm thread. It is the measure of the inclination of a screw thread from a plane perpendicular to the axis of the screw. 螺紋或蝸桿螺紋的螺旋角。它是螺紋從垂直于螺釘軸線的平面的傾斜度的量度。 |
| Lead of thread | 螺紋導程 |
On a single threaded screw, the distance the screw or nut advances in one complete revolution. 在單螺紋螺釘上，螺釘或螺母在一整圈中前進的距離。 |
| Lead screw | 絲杠 |
The master screw running along the length of the bed of a lathe from which all screws threads on that machine are cut. Master screw used for cutting a screw thread in a lathe. 沿車床床身長度方向運行的主螺釘，該機床上的所有螺釘和螺紋都從主螺釘上切割下來。用于在車床上切削螺紋的主螺釘。 |
| Least count | 最小計數 |
The smallest value that can be read from an instrument having a graduated scale. Except on instruments provided with a vernier, the least count is that fraction of the smallest division which can be conveniently and reliably estimated; this fraction is ordinarily one-fifth or one-tenth, except where the graduations are very closely spaced. 可從具有刻度尺的儀器中讀取的最小值。除配備游標的儀器外，最小計數是可以方便可靠地估計的最小除法的分數；這個分數通常是五分之一或十分之一，除非刻度間隔非常近。 |
| Left hand screw | 左螺旋 |
One that screws into the mating part or advances when turned to the left or counter clockwise. 旋入配合部分或向左或逆時針旋轉時前進的螺釘。 |
| Length of engagement | 嚙合長度 |
It is the axial measurement within which the external and internal threads have theoretical contact. 它是外螺紋和內螺紋具有理論接觸的軸向測量。 |
| Linear (tensile or compressive) strain | 線性（拉伸或壓縮）應變 |
The change per unit length due to force in an original linear dimension. An increase in length is considered positive. 由于原始線性尺寸中的力，每單位長度的變化。長度的增加被認為是正的。 |
| Linear-elastic fracture mechanics | 線彈性斷裂力學 |
A method of fracture analysis that can determine the stress (or load) required to induce fracture instability in a structure containing a cracklike flaw of known size and shape. 一種斷裂分析方法，可確定在含有已知尺寸和形狀裂紋狀缺陷的結構中引起斷裂不穩定性所需的應力（或載荷）。 |
| Liquation temperature | 液化溫度 |
The lowest temperature at which partial melting can occur in an alloy that exhibits the greatest possible degree of segregation. 偏析程度最高的合金發生部分熔融的最低溫度。 |
| Liquid carburizing | 液體滲碳 |
Surface hardening of steel by immersion into a molten bath consisting of cyanides and other salts. 通過浸入由氰化物和其他鹽組成的熔池中對鋼進行表面硬化。 |
| Liquid nitriding | 液體氮化 |
A method of surface hardening in which molten nitrogen-bearing, fused-salt baths containing both cyanides and cyanates are exposed to parts at subcritical temperatures. 一種表面硬化方法，其中含有氰化物和氰酸鹽的熔融含氮熔鹽浴在亞臨界溫度下暴露于零件。 |
| Load | 負載 |
For testing machines, a force applied to a test piece that is measured in units such as pound-force, newton, or kilogram-force. 對于試驗機，施加在試件上的力，以磅力、牛頓或千克力等單位測量。 |
| Load and resistance factor design | 負載和阻力系數設計 |
A design procedure developed for the AISC by the Research Council on Structural Connections. Assigns uncertainties in the strength of (i.e., resistance of) and in the service loads to be placed on a shear joint to estimate the probable strength of the joint. It is a recently defined alternative to the Allowable stress design procedure. 結構連接研究委員會為AISC制定的設計程序。分配剪切接頭的強度（即阻力）和工作荷載的不確定性，以估計接頭的可能強度。它是最近定義的容許應力設計程序的替代方案。 |
| Load factor (F) | 負載系數（F） |
The ratio between an increase in bolt tension and the external load which has caused the increase. Factors reflecting the probability of an increase in load in a shear joint. Used in load and resistant factor design. 螺栓張力增加與導致增加的外部載荷之間的比率。反映剪切接縫中荷載增加概率的系數。用于載荷和阻力系數設計。 |
| Load range, P | 負載范圍P |
In fatigue, the algebraic difference between the maximum and minimum loads in a fatigue cycle. 在疲勞中，疲勞循環中最大和最小載荷之間的代數差。 |
| Load ratio, R | 負載比R |
In fatigue, the algebraic ratio of the minimum to maximum load in a fatigue cycle, that is, R = Pmin/Pmax. Also known as stress ratio. 在疲勞中，疲勞循環中最小載荷與最大載荷的代數比，即 R= Pmin/Pmax。也稱為應力比。 |
| Lobe | 凸輪 |
The projecting part such as rotor lobe or the cam lobe. 轉子凸角或凸輪凸角等突出部分。 |
| Lock nut | 鎖緊螺母 |
A type of nut that is prevented from loosening under vibration. The locking action is accomplished by squeezing, gripping or jamming against the bolt threads. A nut which provides extra resistance to vibration loosening (beyond that produced by proper Preload ), either by providing some form of Prevailing torque, or, in free-spinning lock nuts, by deforming, cramping, or biting into mating parts when fully tightened. 1. A thin auxiliary nut tightened against another nut to prevent loosening. 2. A single nut with special features that prevent loosening. 一種在振動下防止松動的螺母。鎖定動作通過擠壓、夾緊或卡住螺栓螺紋來完成。通過提供某種形式的主要扭矩，或在自由旋轉鎖緊螺母中，通過完全擰緊時變形、夾緊或咬入配合零件，提供額外的抗振動松動能力（超出適當預載產生的能力）。1.一個薄的輔助螺母，擰緊到另一個螺母上以防止松動。2.具有防止松動的特殊功能的單個螺母。 |
| Lock-nut pipe thread | 鎖緊螺母管螺紋 |
The lock-nut pipe thread is a straight thread of the largest diameter which can be cut on a pipe. Its form is identical with that of the American or Briggs standard taper pipe thread. In general, “Go” gages only are required. These consist of a straight-threaded plug representing the minimum female lock-nut thread, and a straight-threaded ring representing the maximum male lock-nut thread. This thread is used only to hold parts together, or to retain a collar on the pipe. It is never used where a tight threaded joint is required. 鎖緊螺母管螺紋是最大直徑的直螺紋，可在管道上切割。其形式與美國或布里格斯標準錐管螺紋相同。一般情況下，只需要通規。它們由一個表示最小內螺紋鎖緊螺母螺紋的直螺紋塞和一個表示最大外螺紋鎖緊螺帽螺紋的直形螺紋環組成。該螺紋僅用于將零件固定在一起，或用于將軸環固定在管道上。切勿使用于需要緊密螺紋接頭的情況下。 |
| Lockbolt | 鎖緊螺栓 |
A fastener which bears a superficial resemblance to a bolt, but which engages a collar (instead of a nut) with annular grooves (instead of threads). The collar is swaged over the grooves on the male fastener to develop preload. 表面上類似于螺栓的緊固件，但與環槽（而不是螺紋）接合的軸環（而不是螺母）。套環在陽緊固件上的凹槽上鍛造，以產生預緊力。 |
| Longitudinal direction | 縱向 |
The principal direction of flow in a worked metal. See also normal direction and transverse direction. 加工金屬中的主要流動方向。另請參見法向和橫向。 |
| Low-E coating | 低輻射涂層 |
(low-emittance coating) A thin metallic or metal-oxide coating on a glass sheet to absorb and reflect infrared radiation. The coating is applied either by a pyrolytic chemical vapour-deposition process (hard coat), or by sputtering (soft coat). （低輻射涂層）玻璃板上的薄金屬或金屬氧化物涂層，用于吸收和反射紅外輻射。通過熱解化學氣相沉積工藝（硬涂層）或濺射（軟涂層）施加涂層。 |
| Lubricant | 潤滑劑 |
Any substance interposed between two surfaces for the purpose of reducing the friction or wear between them. 為了減少兩個表面之間的摩擦或磨損而置于兩個表面間的任何物質。 |
| Lüders lines | 呂德斯線 |
Elongated surface markings or depressions, often visible with the unaided eye, that form along the length of sheet metal or a tension specimen at an angle of approximately 45° to the loading axis. Caused by localized plastic deformation, they result from discontinuous (inhomogeneous) yielding. Also known as Lüders bands, Hartmann lines, Piobert lines, or stretcher strains. 拉長的表面標記或凹陷，通常肉眼可見，沿金屬板或拉伸試樣的長度形成，與加載軸的角度約為45°。由于局部塑性變形，它們是不連續（不均勻）屈服的結果。也被稱為呂德斯帶、哈特曼線、皮奧伯特線或拉伸線。 |