When approaching an Android smartphone, there is no straightforward route to physical acquisition. Is the device encrypted? Do you happen to know the passcode? Do you have a bootloader that is unlocked (or at least semi-unlocked)? Does the device have root access installed, or do you have the means to root it? Is a service backdoor available on a particular model? Depending on these factors, you may be able to pursue one or another acquisition method.
Before we go on discussing the various physical acquisition methods, let's make one thing clear: device encryption may affect your ability to access user data. There may be a possibility to extract decryption keys, which in turn, depends on the version of Android and whether or not the phone was made by Samsung.
Prior to Android 5.0 Lollipop, Google used to utilize (and push to Android Open Source Project (AOSP)) a seriously flawed encryption method. This method was compromised as experts were able to extract...